Implementation of sonopartogram: multicenter feasibility study

OBJECTIVES

Well-established clinical practice to assess progress in labor involves routine abdominal palpation and vaginal examination (VE). However, VE is subjective, poorly reproducible and painful for women. In this study, our aim is to evaluate the feasibility of systematically integrating transabdominal and transperineal ultrasound assessment of fetal position, psAOP, HPD and SCD to monitor labor progress in women undergoing induction of labor (IOL). We also aim at determining if ultrasound can reduce women's pain during examinations.

METHODS

Women were recruited as they presented for IOL in three maternity units. Ultrasound assessments were performed in 100 women between 37+0 and 41+6 weeks' gestation. A baseline combined transabdominal and transperineal scan was performed, including the assessment of fetal biometry, umbilical artery and middle cerebral artery Dopplers, amniotic fluid index (AFI), fetal spine and occiput positions, psAOP, HPD, SCD, and cervical length. Intrapartum scans were performed instead of VEs according to protocol. Participants were asked to indicate their level of pain by verbally giving a pain score from 0 - 10 (with 0 representing no pain) during assessment. The repeated measures data were analyzed by mixed effect models to identify the significant factors that affected the relationship between psAOP, HPD, SCD and mode of delivery.

RESULTS

223 intrapartum ultrasound scans with a median of 2 scans per participant (interquartile range (IQR) = 1 - 3), and 151 VEs were performed with a median of 1 per participant (IQR = 0 - 2). There were no adverse fetal or maternal outcomes. After excluding those with epidural anesthesia during examination, median pain score for intrapartum scan was 0 (IQR = 0 - 1) and 3 for VE (IQR = 0 - 6). Cesarean delivery and epidural anesthesia were significantly associated with slower rate of change in psAOP, HPD and SCD. Maternal height, parity and neonatal birth weight did not affect ultrasound measurements of labor progress.

CONCLUSIONS

Comprehensive transabdominal and transperineal ultrasound assessment can be successfully used to assess progress in labor and can reduce the level of pain experienced during examination. Ultrasound assessment may be able to replace some transabdominal and VE examinations during labor. This article is protected by copyright. All rights reserved.

Evaluation of screening performance of first-trimester competing-risks prediction model for small-for-gestational age in Asian population

OBJECTIVE

To examine the external validity of the Fetal Medicine Foundation (FMF) competing-risks model for the prediction of small-for-gestational age (SGA) at 11-14 weeks' gestation in an Asian population.

METHODS

This was a secondary analysis of a multicenter prospective cohort study in 10 120 women with a singleton pregnancy undergoing routine assessment at 11-14 weeks' gestation. We applied the FMF competing-risks model for the first-trimester prediction of SGA, combining maternal characteristics and medical history with measurements of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) and serum placental growth factor (PlGF) concentration. We calculated risks for different cut-offs of birth-weight percentile (< 10th , < 5th or < 3rd percentile) and gestational age at delivery (< 37 weeks (preterm SGA) or SGA at any gestational age). Predictive performance was examined in terms of discrimination and calibration.

RESULTS

The predictive performance of the competing-risks model for SGA was similar to that reported in the original FMF study. Specifically, the combination of maternal factors with MAP, UtA-PI and PlGF yielded the best performance for the prediction of preterm SGA with birth weight < 10th percentile (SGA < 10th ) and preterm SGA with birth weight < 5th percentile (SGA < 5th ), with areas under the receiver-operating-characteristics curve (AUCs) of 0.765 (95% CI, 0.720-0.809) and 0.789 (95% CI, 0.736-0.841), respectively. Combining maternal factors with MAP and PlGF yielded the best model for predicting preterm SGA with birth weight < 3rd percentile (SGA < 3rd ) (AUC, 0.797 (95% CI, 0.744-0.850)). After excluding cases with pre-eclampsia, the combination of maternal factors with MAP, UtA-PI and PlGF yielded the best performance for the prediction of preterm SGA < 10th and preterm SGA < 5th , with AUCs of 0.743 (95% CI, 0.691-0.795) and 0.762 (95% CI, 0.700-0.824), respectively. However, the best model for predicting preterm SGA < 3rd without pre-eclampsia was the combination of maternal factors and PlGF (AUC, 0.786 (95% CI, 0.723-0.849)). The FMF competing-risks model including maternal factors, MAP, UtA-PI and PlGF achieved detection rates of 42.2%, 47.3% and 48.1%, at a fixed false-positive rate of 10%, for the prediction of preterm SGA < 10th , preterm SGA < 5th and preterm SGA < 3rd , respectively. The calibration of the model was satisfactory.

CONCLUSION

The screening performance of the FMF first-trimester competing-risks model for SGA in a large, independent cohort of Asian women is comparable with that reported in the original FMF study in a mixed European population. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Longitudinal evaluation of cervical length and shear wave elastography in women with spontaneous preterm birth

OBJECTIVES

To compare longitudinal changes in cervical length (CL) and mean cervical shear wave elastography (CSWE) scores between women with singleton and twin pregnancies who experience spontaneous preterm birth (sPTB) and those who have term births (TB).

METHODS

This was a prospective longitudinal study of 1264 unselected women with singleton (n=1143) and twin (n=121) pregnancy attending a dedicated research clinic for screening of sPTB at 4 timepoints during pregnancy including 11-15+6 (visit 1), 16-20+6 (visit 2), 21-24+6 (visit 3) and 28-32+6 (visit 4) weeks of gestation. At each visit, a transvaginal ultrasound scan was conducted to measure the CL and the CSWE scores from six regions of interest (ROI) (inner, middle, and external parts of anterior and posterior lips) in the cervix. The mean of CSWE scores from the six ROIs were calculated for data analysis. Log10 transformation was applied to make the data Gaussian prior to statistical analysis. A multilevel mixed-effects analysis was performed to compare CL and CSWE longitudinally between sPTB and TB groups.

RESULTS

A total of 57 (4.99%) singleton pregnancies and 33 (27.27%) twin pregnancies were complicated with sPTB. Women with sPTB had shorter CL across gestation when controlling for history of cervical surgery, number of fetuses, gestational age at cervical assessment (GA), and the interaction between GA and sPTB. CL in the sPTB group was significantly lower than that of the TB group at 21-24+6 weeks (p=0.039) and 28-32+6 weeks (p<0.001). Twin pregnancies had significantly longer CL throughout pregnancy, compared to singleton pregnancies (coefficient=0.01864, p<0.001). Furthermore, after adjusting for maternal age, weight, height, body mass index (BMI), and GA, CSWE scores in sPTB group were significantly lower in the sPTB group across gestation, compared to the TB group (1.28265 vs 1.32832; p=0.013). However, in the individual visit analysis, CSWE scores in the sPTB group were significantly lower than that of the TB group only at 11-15+6 weeks (p=0.013). There was no difference in CSWE scores between singleton and twin pregnancies throughout pregnancy (coefficient=-0.00128, p=0.937).

CONCLUSION

Women with sPTB have shorter CL and softer cervix across gestation when compared to those with TB. In the individual visit analysis, the reduction in CL in the sPTB group occurs from late second trimester onwards, while the reduction in cervical stiffness in the sPTB group is observed primarily in the first trimester. Additionally, our study has found that CL is significantly shorter in singleton pregnancies compared to twin pregnancies, while cervical stiffness does not differ between the two types of pregnancy. Our findings indicate that the cervix tends to undergo a softening process prior to shortening in the sPTB cases This article is protected by copyright. All rights reserved.

Pharmacogenomics of Preeclampsia therapies: Current evidence and future challenges for clinical implementation

Preeclampsia is a pregnancy-specific disorder, and it is a leading cause of maternal and perinatal morbidity and mortality. The application of pharmacogenetics to antihypertensive agents and dose selection in women with preeclampsia is still in its infancy. No current prescribing guidelines from the clinical pharmacogenetics implementation consortium (CPIC) exist for preeclampsia. Although more studies on pharmacogenomics are underway, there is some evidence for the pharmacogenomics of preeclampsia therapies, considering both the pharmacokinetic (PK) and pharmacodynamic (PD) properties of drugs used in preeclampsia. It has been revealed that the CYP2D6*10 variant is significantly higher in women with preeclampsia who are non-responsive to labetalol compared to those who are in the responsive group. Various genetic variants of PD targets, i.e., NOS3, MMP9, MMP2, TIMP1, TIMP3, VEGF, and NAMPT, have been investigated to assess the responsiveness of antihypertensive therapies in preeclampsia management, and they indicated that certain genetic variants of MMP9, TIMP1, and NAMPT are more frequently observed in those who are non-responsive to anti-hypertensive therapies compared to those who are responsive. Further, gene-gene interactions have revealed that NAMPT, TIMP1, and MMP2 genotypes are associated with an increased risk of preeclampsia, and they are more frequently observed in the non-responsive subgroup of women with preeclampsia. The current evidence is not rigorous enough for clinical implementation; however, an institutional or regional-based retrospective analysis of audited data may help close the knowledge gap during the transitional period from a traditional approach (a "one-size-fits-all" strategy) to the pharmacogenomics of preeclampsia therapies.

Prediction by uterine artery Doppler screening of small-for-gestational-age neonates at 19-24 weeks' gestation

OBJECTIVE

Small-for-gestational-age (SGA) neonates are at increased risk of perinatal mortality and morbidity. We aimed to investigate the performance of uterine artery pulsatility index (UtA-PI) at 19-24 weeks' gestation to predict the delivery of a SGA neonate in a Chinese population.

METHODS

This was a retrospective cohort study using data obtained between January 2010 and June 2018. Doppler ultrasonography was performed at 19-24 weeks' gestation. SGA was defined as birth weight below the 10th centile according to the INTERGROWTH-21st fetal growth standards. The performance of UtA-PI to predict the delivery of a SGA neonate was assessed using receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

We included 6964 singleton pregnancies, of which 748 (11%) delivered a SGA neonate, including 115 (15%) women with preterm delivery. Increased UtA-PI was associated with an elevated risk of SGA, both in neonates delivered at or after 37 weeks' gestation (term SGA) and those delivered before 37 weeks (preterm SGA). The areas under the ROC curve (AUCs) for UtA-PI were 64.4% (95% CI, 61.5-67.3%) and 75.8% (95% CI, 69.3-82.3%) for term and preterm SGA, respectively. The performance of combined screening by maternal demographic/clinical characteristics and estimated fetal weight in the detection of term and preterm SGA was improved significantly by the addition of UtA-PI, although the increase in AUC was modest (2.4% for term SGA and 4.9% for preterm SGA).

CONCLUSIONS

This is the first Chinese study to evaluate the role of UtA-PI at 19-24 weeks' gestation in the prediction of the delivery of a neonate with SGA. The addition of UtA-PI to traditional risk factors improved the screening performance for SGA, and this improvement was greater in predicting preterm SGA compared with term SGA. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Glycosylated fibronectin improves first-trimester prediction of pre-eclampsia

OBJECTIVE

To determine whether maternal serum glycosylated fibronectin (GlyFn) level in the first trimester increases the sensitivity of the Fetal Medicine Foundation (FMF) triple test, which incorporates mean arterial pressure, uterine artery pulsatility index and placental growth factor, when screening for pre-eclampsia (PE) in an Asian population.

METHODS

This was a nested case-control study of Chinese women with a singleton pregnancy who were screened for PE at 11-13 weeks' gestation as part of a non-intervention study between December 2016 and June 2018. GlyFn levels were measured retrospectively in archived serum from 1685 pregnancies, including 101 with PE, using an enzyme-linked immunosorbent assay (ELISA), and from 448 pregnancies, including 101 with PE, using a point-of-care (POC) device. Concordance between ELISA and POC tests was assessed using Lin's correlation coefficient and Passing-Bablok and Bland-Altman analyses. GlyFn was transformed into multiples of the median (MoM) to adjust for maternal and pregnancy characteristics. GlyFn MoM was compared between PE and non-PE pregnancies, and the association between GlyFn MoM and gestational age at delivery with PE was assessed. Risk for developing PE was estimated using the FMF competing-risks model. Screening performance for preterm and any-onset PE using different biomarker combinations was quantified by area under the receiver-operating-characteristics curve (AUC) and detection rate (DR) at a 10% fixed false-positive rate (FPR). Differences in AUC between biomarker combinations were compared using the DeLong test.

RESULTS

The concordance correlation coefficient between ELISA and POC measurements was 0.86 (95% CI, 0.83-0.88). Passing-Bablok analysis indicated proportional bias (slope, 1.08 (95% CI, 1.04-1.14)), with POC GlyFn being significantly higher compared with ELISA GlyFn. ELISA GlyFn in non-PE pregnancies was independent of gestational age at screening (P = 0.11), but significantly dependent on maternal age (P < 0.003), weight (P < 0.0002), height (P = 0.001), parity (P < 0.02) and smoking status (P = 0.002). Compared with non-PE pregnancies, median GlyFn MoM using ELISA and POC testing was elevated significantly in those with preterm PE (1.23 vs 1.00; P < 0.0001 and 1.18 vs 1.00; P < 0.0001, respectively) and those with term PE (1.26 vs 1.00; P < 0.0001 and 1.22 vs 1.00; P < 0.0001, respectively). GlyFn MoM was not correlated with gestational age at delivery with PE (P = 0.989). Adding GlyFn to the FMF triple test for preterm PE increased significantly the AUC from 0.859 to 0.896 (P = 0.012) and increased the DR at 10% FPR from 64.9% (95% CI, 48.7-81.1%) to 82.9% (95% CI, 66.4-93.4%). The corresponding DRs at 10% FPR for any-onset PE were 52.5% (95% CI, 42.3-62.5%) and 65.4% (95% CI, 55.2-74.5%), respectively.

CONCLUSIONS

Adding GlyFn to the FMF triple test increased the screening sensitivity for both preterm and any-onset PE in an Asian population. Prospective non-intervention studies are needed to confirm these initial findings. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

ASPRE trial: effects of aspirin on mean arterial blood pressure and uterine artery pulsatility index trajectories in pregnancy

OBJECTIVES

The mechanism by which aspirin prevents pre-eclampsia is poorly understood, and its effects on biomarkers throughout pregnancy are unknown. We aimed to investigate the effects of aspirin on mean arterial pressure (MAP) and mean uterine artery pulsatility index (UtA-PI) using repeated measures from women at increased risk of preterm pre-eclampsia.

METHODS

This was a longitudinal secondary analysis of the Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Pre-eclampsia Prevention (ASPRE) trial using repeated measures of MAP and UtA-PI. In the trial, 1620 women at increased risk of preterm pre-eclampsia were identified using the Fetal Medicine Foundation algorithm at 11 + 0 to 13 + 6 weeks, of whom 798 were randomly assigned to receive 150 mg/day aspirin and 822 were assigned to receive placebo daily from 11-14 weeks to 36 weeks of gestation or delivery, whichever came first. MAP and UtA-PI were measured at baseline and follow-up visits at 19-24, 32-34 and 36 weeks of gestation. Generalized additive mixed models with treatment by gestational age interaction terms were used to investigate the effects of aspirin on MAP and UtA-PI trajectories over time.

RESULTS

Among 798 participants in the aspirin group and 822 in the placebo group, there were 5951 MAP and 5942 UtA-PI measurements. Trajectories of raw and multiples of the median (MoM) values of MAP did not differ significantly between the two groups (MAP MoM analysis: P-value for treatment by gestational age interaction, 0.340). In contrast, trajectories of raw and MoM values of UtA-PI showed a significantly steeper decline in the aspirin group than in the placebo group, with the difference mainly driven by a more pronounced reduction before 20 weeks of gestation (UtA-PI MoM analysis: P-value for treatment by gestational age interaction, 0.006).

CONCLUSIONS

In women at increased risk of preterm pre-eclampsia, 150 mg/day aspirin initiated in the first trimester does not affect MAP but is associated with a significant decrease in mean UtA-PI, particularly before 20 weeks of gestation. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of spontaneous preterm birth and preterm prelabor rupture of membranes using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks

OBJECTIVES

To determine whether first-trimester biomarkers of placental function can be used to screen for spontaneous preterm birth (sPTB), and to develop prediction models using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks for the calculation of patient-specific risk for sPTB.

METHODS

This was a retrospective secondary analysis of data derived from a prospective cohort study on first-trimester screening for pre-eclampsia in singleton pregnancies attending for routine Down syndrome screening at 11 + 0 to 13 + 6 weeks' gestation at a tertiary obstetric unit between December 2016 and September 2019. A split-sample internal validation method was used to explore and develop prediction models for all sPTB at < 37 weeks and for PTB at < 37 weeks after preterm prelabor rupture of membranes (PPROM) using maternal risk factors, uterine artery Doppler indices, serum placental growth factor (PlGF), pregnancy-associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG). Screening performance was assessed using receiver-operating-characteristics (ROC)-curve analysis, with calculation of the areas under the ROC curves (AUCs).

RESULTS

A total of 9298 singleton pregnancies were included in this study. sPTB at < 37 weeks occurred in 362 (3.89%) cases, including 231 (2.48%) cases of PPROM. sPTB at < 34 weeks occurred in 87 (0.94%) cases, including 39 (0.42%) cases of PPROM. Identified maternal risk factors for sPTB at < 37 weeks included chronic hypertension, conception using in-vitro fertilization and history of PTB. Maternal risk factors for PPROM at < 37 weeks included conception using in-vitro fertilization and history of PTB. Median PlGF multiples of the median (MoM) and PAPP-A MoM were significantly reduced in women with sPTB at < 37 weeks, as well as in those who had PPROM, compared to those who delivered at term. Screening by a combination of maternal risk factors, PAPP-A and PlGF achieved better performance in predicting sPTB at < 37 weeks (AUC, 0.630 vs 0.555; detection rate (DR), 24.8% vs 16.6% at a false-positive rate (FPR) of 10%; P ≤ 0.0001) and PPROM at < 37 weeks (AUC, 0.643 vs 0.558; DR, 28.1% vs 17.0% at a FPR of 10%; P ≤ 0.0001) than using maternal risk factors alone. Both models were successfully applied to the internal validation dataset, with AUCs of 0.628 and 0.650, respectively.

CONCLUSIONS

We demonstrated that low levels of maternal serum PAPP-A and PlGF in the first trimester are associated with increased risks of sPTB and PPROM at < 37 weeks. However, further research is needed to identify additional biomarkers to improve the screening performance of the combined model that includes maternal risk factors, PAPP-A and PlGF before clinical application. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Impact of replacing or adding pregnancy-associated plasma protein-A at 11-13 weeks on screening for preterm pre-eclampsia

OBJECTIVE

To assess whether pregnancy-associated plasma protein-A (PAPP-A) alters or provides equivalent screening performance as placental growth factor (PlGF) when screening for preterm pre-eclampsia (PE) at 11-13 weeks of gestation.

METHODS

This was a secondary analysis of a non-intervention screening study of 6546 singleton pregnancies that were screened prospectively for preterm PE in the first trimester between December 2016 and June 2018. Patient-specific risks for preterm PE were estimated by maternal history, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), PlGF and PAPP-A. A competing-risks model with biomarkers expressed as multiples of the median was used. All women and clinicians were blinded to the risk for preterm PE. The performance of screening for preterm PE using PlGF vs PAPP-A vs both PAPP-A and PlGF was assessed by comparing areas under the receiver-operating-characteristics (AUC) curves. McNemar's test was used to compare detection rate at a fixed false-positive rate (FPR) of 10%.

RESULTS

PlGF and PAPP-A were measured in 6546 women, of whom 37 developed preterm PE. The AUC and detection rate at 10% FPR using PlGF in combination with maternal history, MAP and UtA-PI were 0.854 and 59.46%, respectively. The respective values were 0.813 and 51.35% when replacing PlGF with PAPP-A and 0.855 and 59.46% when using both PAPP-A and PlGF. Statistically non-significant differences were noted in AUC when replacing PlGF with PAPP-A (ΔAUC, 0.04; P = 0.095) and when using both PAPP-A and PlGF (ΔAUC, 0.002; P = 0.423). However, on an individual case basis, screening using PlGF in conjunction with maternal history, MAP and UtA-PI identified three (8.1%) additional pregnancies that developed preterm PE and that were not identified when replacing PlGF with PAPP-A. Screening using PAPP-A in addition to maternal history and other biomarkers did not identify any additional pregnancies.

CONCLUSION

On an individual case basis, adoption of a screening strategy that uses PAPP-A instead of PlGF results in reduced detection of preterm PE, consistent with previous literature. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

ASPRE trial: risk factors for development of preterm pre-eclampsia despite aspirin prophylaxis

OBJECTIVE

To examine the possible risk factors amongst maternal characteristics, medical and obstetric history, pre-eclampsia (PE)-specific biomarkers and estimated-risk group, according to The Fetal Medicine Foundation (FMF) algorithm, that are associated with the development of preterm PE with delivery at < 37 weeks' gestation despite aspirin prophylaxis.

METHODS

This was a secondary analysis of data from the ASPRE trial. The study population consisted of women with singleton pregnancy who were deemed to be at high risk for preterm PE, based on the FMF algorithm that combines maternal factors, mean arterial pressure, uterine artery pulsatility index, serum pregnancy-associated plasma protein-A and placental growth factor (PlGF) at 11-13 weeks' gestation. High-risk women were randomized to receive aspirin (150 mg/day) vs placebo from 11-14 until 36 weeks' gestation. The primary outcome was PE with delivery at < 37 weeks' gestation (preterm PE). Multivariate logistic regression analysis was performed to identify independent predictors of preterm PE after adjusting for the use of aspirin and other covariates.

RESULTS

Among 1592 high-risk women, the incidence of preterm PE was 3.0% (n = 48). The interaction between aspirin usage and history of chronic hypertension was significant in the prediction of preterm PE (P = 0.042), which indicated that there was no treatment effect in high-risk women who had chronic hypertension compared with those who did not. Adjusting for aspirin use, the interaction between aspirin and chronic hypertension and other covariates, independent predictors for the development of preterm PE were PlGF multiples of the median (MoM) (adjusted odds ratio (aOR), 0.226 (95% CI, 0.070-0.723)) and estimated-risk group based on the FMF algorithm. Compared to women with an estimated risk of 1 in 51 to 1 in 100, those with an estimated risk of 1 in 2 to 1 in 10 had a 7-fold higher risk of developing preterm PE (aOR, 6.706 (95% CI, 2.381-18.883)), and those with an estimated risk of 1 in 11 to 1 in 50 had a 3-fold higher risk of preterm PE (aOR, 2.769 (95% CI, 1.105-6.939)). PlGF MoM was an independent predictor for preterm PE among women with an estimated risk of 1 in 2 to 1 in 10 (aOR, 0.055 (95% CI, 0.005-0.668)). Among women with an estimated risk of 1 in 11 to 1 in 100, the use of aspirin was an independent predictor of preterm PE (aOR, 0.276 (95% CI, 0.111-0.689)). The cut-off for PlGF with the best performance for the prediction of preterm PE was 0.712 MoM, with an aOR of 3.677 (95% CI, 1.526-8.862).

CONCLUSION

In pregnancies at high risk of preterm PE identified by screening at 11-13 weeks' gestation using the FMF algorithm, a very high-risk result (estimated risk ≥ 1 in 50), compared to an estimated risk of 1 in 51 to 1 in 100, chronic hypertension, compared to no chronic hypertension, and low PlGF concentration (< 0.712 MoM), compared to PlGF ≥ 0.712 MoM, were associated with the development of preterm PE despite aspirin prophylaxis. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Transperineal ultrasound assessment of fetal head elevation by maneuvers used for managing umbilical cord prolapse

OBJECTIVE

To assess objectively the degree of fetal head elevation achieved by different maneuvers commonly used for managing umbilical cord prolapse.

METHODS

This was a prospective observational study of pregnant women at term before elective Cesarean delivery. A baseline assessment of fetal head station was performed with the woman in the supine position, using transperineal ultrasound for measuring the parasagittal angle of progression (psAOP), head-symphysis distance (HSD) and head-perineum distance (HPD). The ultrasonographic measurements of fetal head station were repeated during different maneuvers, including elevation of the maternal buttocks using a wedge, knee-chest position, Trendelenburg position with a 15° tilt and filling the maternal urinary bladder with 100 mL, 300 mL and 500 mL of normal saline. The measurements obtained during the maneuvers were compared with the baseline measurements.

RESULTS

Twenty pregnant women scheduled for elective Cesarean section at term were included in the study. When compared with baseline (median psAOP, 103.6°), the knee-chest position gave the strongest elevation effect, with the greatest reduction in psAOP (psAOP, 80.7°; P < 0.001), followed by filling the bladder with 500 mL (psAOP, 89.9°; P < 0.001) and 300 mL (psAOP, 94.4°; P < 0.001) of normal saline. Filling the maternal bladder with 100 mL of normal saline (psAOP, 96.1°; P = 0.001), the Trendelenburg position (psAOP, 96.8°; P = 0.014) and elevating the maternal buttocks (psAOP, 98.3°; P = 0.033) gave modest elevation effects. Similar findings were reported for HSD and HPD. The fetal head elevation effects of the knee-chest position, Trendelenburg position and elevation of the maternal buttocks were independent of the initial fetal head station, but that of bladder filling was greater when the initial head station was low.

CONCLUSIONS

To elevate the fetal presenting part, the knee-chest position provides the best effect, followed by filling the maternal urinary bladder with 500 mL then 300 mL of fluid, respectively. Filling the bladder with 100 mL of fluid, the Trendelenburg position and elevation of the maternal buttocks have modest effects. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Incidence of pre-eclampsia and other perinatal complications among pregnant women with congenital heart disease: systematic review and meta-analysis

OBJECTIVE

It has been proposed recently that pre-eclampsia (PE) may originate from maternal cardiac maladaptation rather than primary placental insult. As congenital heart disease (CHD) is associated with reduced adaptation to the hemodynamic needs of pregnancy, it is hypothesized that women with CHD have an increased risk of PE. The aim of this systematic review was to investigate the risk of PE in pregnant women with CHD.

METHODS

A systematic search was performed to identify relevant studies published in English, Spanish, French, Italian, Chinese or German, with no time restrictions, using databases such as PubMed, Web of Science and SCOPUS. Randomized controlled trials and observational studies (prospective or retrospective cohorts) of pregnant women with a history of CHD were sought. The main outcome was the incidence of PE (including eclampsia and HELLP syndrome). For quality assessment of the included studies, two reviewers assessed independently the risk of bias. For the meta-analysis, the incidence of PE in pregnancies (those beyond 20 weeks' gestation) was calculated using single-proportion analysis by random-effects modeling (weighted by inverse variance). Heterogeneity between studies was assessed using the χ² (Cochran's Q), tau² and I² statistics. Subgroup analysis was performed, and meta-regression was used to assess the influence of several covariates on the pooled results.

RESULTS

A total of 33 studies were included in the meta-analysis, including 40 449 women with CHD and a total of 40 701 pregnancies. The weighted incidence of PE was 3.1% (95% CI, 2.2-4.0%), with true-effect heterogeneity of 93% according to I² , and no publication bias found. No difference was found in the weighted incidence of PE between studies including cyanotic CHD vs those excluding (or not reporting) cyanotic CHD (2.5% (95% CI, 1.6-3.4%) vs 4.1% (95% CI, 2.4-5.7%); P = 0.0923). Meta-regression analysis showed that the only cofactor that significantly influenced the incidence of PE in each study was the reported incidence of aortic stenosis; studies with a higher incidence of aortic stenosis had a higher incidence of PE (estimate: 0.0005; P = 0.038).

CONCLUSIONS

We failed to demonstrate an incidence of PE above the expected baseline risk in women with CHD. This observation contradicts the theory of the cardiac origin of PE. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Pregnant women with SARS-CoV-2 infection are at higher risk of death and pneumonia: propensity score matched analysis of a nationwide prospective cohort (COV19Mx)

OBJECTIVE

There are limited, unmatched data reporting low complication rates in pregnant women with coronavirus disease 2019 (COVID-19). The aim of this study was to compare COVID-19-related outcomes between pregnant and non-pregnant women after adjusting for potential risk factors for severe outcomes.

METHODS

Data were obtained from the COVID-19 National Data Registry of Mexico, which is an ongoing prospective cohort of people of any age with clinically suspected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and admitted to 475 monitoring hospitals. This study included pregnant and non-pregnant women of reproductive age (15-45 years) with COVID-19 confirmed by reverse transcription polymerase chain reaction. To adjust for underlying risk factors, propensity score matching was conducted for chronic obstructive pulmonary disease, asthma, smoking, hypertension, cardiovascular disease, obesity, diabetes, chronic renal disease, immunosuppression, age, language, nationality and level of health insurance. The primary outcome was death. Secondary outcomes were pneumonia, intubation and intensive care unit (ICU) admission.

RESULTS

The cohort comprised 5183 pregnant and 175 905 non-pregnant women with COVID-19. The crude (unmatched) rates of death, pneumonia, intubation and ICU admission in pregnant compared with non-pregnant women were 1.5% vs 1.5%, 9.9% vs 6.5%, 8.1% vs 9.9% and 13.0% vs 6.9%, respectively. After propensity score matching (5183 pregnant and 5183 non-pregnant matched women), pregnant women had a higher odds of death (odds ratio (OR), 1.84; 95% CI, 1.26-2.69), pneumonia (OR, 1.86; 95% CI, 1.60-2.16) and ICU admission (OR, 1.86; 95% CI, 1.41-2.45) than non-pregnant women, but similar odds of intubation (OR, 0.93; 95% CI, 0.70-1.25).

CONCLUSION

After adjusting for background demographic and medical factors, pregnancy is a risk factor for death, pneumonia and ICU admission in SARS-CoV-2-infected women of reproductive age. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The significance of low first trimester serum progesterone in ongoing early pregnancies presenting as pregnancies of unknown location

OBJECTIVES

The primary objective of this study was to ascertain whether there is association between low initial serum progesterone, sonographic parameters and clinical outcomes in women presenting with pregnancies of unknown location (PUL), which are found to be ongoing at their follow up scans in the first trimester.

STUDY DESIGN

This was a non-interventional retrospective cohort study of 1056 patients spanning a 14-year period, conducted in the Early Pregnancy Unit (EPU) of an inner-city teaching hospital. Patients who had an ongoing singleton first trimester pregnancy after presenting with PUL were identified and categorised as having low progesterone if it was 32 nmol/l or lower. The crown-rump length (CRL), mean gestational sac diameter (MGSD) and gestational sac volume (GSV) were measured when the embryo was first seen, and the pregnancy outcome recorded.

RESULTS

Pregnancies with low progesterone tended to have smaller gestational sacs (GS) on follow up scan (p = 0.001) and the sac was smaller than expected for a given CRL (p = 0.000). There was no ultrasound parameter that was characteristic of low progesterone. The observation of a smaller than expected MGSD for a given CRL remained even when only pregnancies with normal outcomes were analysed. Clinical outcome data were available for 854 (80.9 %) women. Overall, 81.4 % (n = 34/43) of pregnancies with low progesterone resulted in livebirth, compared to 91.7 % (n = 744/811) livebirths in pregnancies with higher levels (p = 0.0454).

CONCLUSION

Pregnancies with low progesterone tend to have a smaller GS compared to those with a higher progesterone, and the GSs are smaller than expected for a given CRL. The current study shows that women with low progesterone at the start of pregnancy remain at higher risk of miscarriage, even when the pregnancy is initially found to be viable in the first trimester. These pregnancies also tend to be associated with the sonographic finding of a smaller GS than expected for a given gestational age, regardless of eventual outcome.

First-trimester pre-eclampsia biomarker profiles in Asian population: multicenter cohort study

OBJECTIVES

To (i) evaluate the applicability of the European-derived biomarker multiples of the median (MoM) formulae for risk assessment of preterm pre-eclampsia (PE) in seven Asian populations, spanning the east, southeast and south regions of the continent, (ii) perform quality-assurance (QA) assessment of the biomarker measurements and (iii) establish criteria for prospective ongoing QA assessment of biomarker measurements.

METHODS

This was a prospective, non-intervention, multicenter study in 4023 singleton pregnancies, at 11 to 13 + 6 weeks' gestation, in 11 recruiting centers in China, Hong Kong, India, Japan, Singapore, Taiwan and Thailand. Women were screened for preterm PE between December 2016 and June 2018 and gave written informed consent to participate in the study. Maternal and pregnancy characteristics were recorded and mean arterial pressure (MAP), mean uterine artery pulsatility index (UtA-PI) and maternal serum placental growth factor (PlGF) were measured in accordance with The Fetal Medicine Foundation (FMF) standardized measurement protocols. MAP, UtA-PI and PlGF were transformed into MoMs using the published FMF formulae, derived from a largely Caucasian population in Europe, which adjust for gestational age and covariates that affect directly the biomarker levels. Variations in biomarker MoM values and their dispersion (SD) and cumulative sum tests over time were evaluated in order to identify systematic deviations in biomarker measurements from the expected distributions.

RESULTS

In the total screened population, the median (95% CI) MoM values of MAP, UtA-PI and PlGF were 0.961 (0.956-0.965), 1.018 (0.996-1.030) and 0.891 (0.861-0.909), respectively. Women in this largely Asian cohort had approximately 4% and 11% lower MAP and PlGF MoM levels, respectively, compared with those expected from normal median formulae, based on a largely Caucasian population, whilst UtA-PI MoM values were similar. UtA-PI and PlGF MoMs were beyond the 0.4 to 2.5 MoM range (truncation limits) in 16 (0.4%) and 256 (6.4%) pregnancies, respectively. QA assessment tools indicated that women in all centers had consistently lower MAP MoM values than expected, but were within 10% of the expected value. UtA-PI MoM values were within 10% of the expected value at all sites except one. Most PlGF MoM values were systematically 10% lower than the expected value, except for those derived from a South Asian population, which were 37% higher.

CONCLUSIONS

Owing to the anthropometric differences in Asian compared with Caucasian women, significant differences in biomarker MoM values for PE screening, particularly MAP and PlGF MoMs, were noted in Asian populations compared with the expected values based on European-derived formulae. If reliable and consistent patient-specific risks for preterm PE are to be reported, adjustment for additional factors or development of Asian-specific formulae for the calculation of biomarker MoMs is required. We have also demonstrated the importance and need for regular quality assessment of biomarker values. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Effect of race on longitudinal central hemodynamics in pregnancy

OBJECTIVE

To compare central hemodynamics between white, black and Asian women in pregnancy.

METHODS

This was a prospective, longitudinal study of maternal central hemodynamics in white, black and Asian women with a singleton pregnancy, assessed using a bioreactance method at 11 + 0 to 13 + 6, 19 + 0 to 24 + 0, 30 + 0 to 34 + 0 and 35 + 0 to 37 + 0 weeks' gestation. At each visit, cardiac output (CO), stroke volume (SV), heart rate (HR), peripheral vascular resistance (PVR) and mean arterial pressure were recorded. Multilevel linear mixed-effects analysis was performed to compare the repeated measures of the cardiac variables between white, black and Asian women, controlling for maternal characteristics, medical history and medication use.

RESULTS

The study population included 1165 white, 247 black and 116 Asian women. CO increased with gestational age to a peak at 32 weeks and then decreased; the highest CO was observed in white women and the lowest in Asian women. SV initially increased after the first visit but subsequently declined with gestational age in white women, decreased with gestational age in black women and remained static in Asian women. In all three study groups, HR increased with gestational age until 32 weeks and then remained constant; HR was highest in black women and lowest in white women. PVR showed a reversed pattern to that of CO; the highest values were in Asian women and the lowest in white women. The least favorable hemodynamic profile, which was observed in black and Asian women, was reflected in higher rates of a small-for-gestational-age infant.

CONCLUSIONS

There are race-specific differences in maternal cardiac adaptation to pregnancy. White women have the most favorable cardiac adaptation by increasing SV and HR, achieving the highest CO and lowest PVR. In contrast, black and Asian women have lower CO and higher PVR than do white women, with CO increasing through a rise in HR due to declining or static SV. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac function in women at high risk for pre-eclampsia treated with 150 mg aspirin or placebo: an observational study

OBJECTIVE

To compare maternal haemodynamics in women at low and high risk for preterm pre-eclampsia (PE), and between those at high risk who are randomised to aspirin or placebo.

DESIGN

Prospective, longitudinal observational study.

SETTING

Maternity units in six UK hospitals.

POPULATION

Women participating in the Aspirin for Prevention of Preterm Pre-eclampsia (ASPRE) trial. The population comprised three groups of women: low risk for preterm PE (n = 1362), high risk for preterm PE treated with aspirin (n = 208) and high risk for preterm PE on placebo (n = 220).

METHODS

Women had four visits during pregnancy: 11-14, 19-24, 30-34, and 35-37 weeks' gestation. Blood pressure was measured with a device validated for pregnancy, and PE and maternal haemodynamics were assessed with a bioreactance monitor at each visit. A multilevel linear mixed-effects analysis was performed to examine longitudinal changes of maternal haemodynamic variables, controlling for demographic characteristics, past medical history and medication use.

MAIN OUTCOME MEASURES

Longitudinal changes of cardiac output (CO), mean arterial pressure (MAP), and peripheral vascular resistance (PVR).

RESULTS

The low-risk group demonstrated the expected changes with an increase in CO and reduction in MAP and PVR, with a quadratic change across gestation. In contrast, the high-risk groups had a declining CO, and higher MAP and PVR during pregnancy. The administration of aspirin did not appear to affect maternal haemodynamics.

CONCLUSIONS

Women screened as high risk for preterm PE have a pathological cardiac adaptation to pregnancy and the prophylactic use of aspirin (150 mg oral daily from the first trimester) in this group may not alter this haemodynamic profile.

TWEETABLE ABSTRACT

In women at high risk of pre-eclampsia, prophylactic use of aspirin may not alter the impaired maternal cardiac adaptation.

Transvaginal three-dimensional ultrasound assessment of Sylvian fissures at 18-30 weeks' gestation

OBJECTIVE

To (1) evaluate the normal development of the Sylvian fissures in the anterior coronal view of the fetal brain at 18-30 weeks' gestation by transvaginal three-dimensional (3D) ultrasound, (2) develop reference ranges of measurements of the right and left Sylvian fissure angles during normal pregnancy at 18-30 weeks' gestation, and (3) examine intra- and interobserver repeatability of measurements of the right and left Sylvian fissure angles.

METHODS

This was a prospective cross-sectional study of 422 women with a singleton pregnancy attending an ultrasound-based research clinic between March and December 2017. The entry criteria for the study were appropriately grown live fetus with no suspected structural and/or chromosomal defects between 18 + 0 and 30 + 6 weeks' gestation. Normal development of the Sylvian fissures was assessed in the anterior coronal plane of the fetal brain using transvaginal 3D volume multiplanar imaging. The coronal view was visualized as a single image from the three orthogonal views. Subsequently, the right and left Sylvian fissure angles were measured between a horizontal reference line (0°) and a line drawn along the upper side of the respective Sylvian fissure. Intra- and interobserver repeatability of the Sylvian fissure angle measurements was assessed by Bland-Altman plots. Reference equations were constructed for right and left Sylvian fissure angles for gestational age (GA) and head circumference (HC) using the Generalized Additive Models for Location Scale and Shape package.

RESULTS

In the anterior coronal view of the fetal brain, an inward rotation of the upper portion of the Sylvian fissures was observed during the second and third trimesters of pregnancy. There was a significant negative polynomial association between the Sylvian fissure angles and GA and HC. Both Sylvian fissure angles crossed the reference line (zero), going from positive to negative, at around 25 weeks' gestation or at HC of 22 cm. Z-score difference between the smoothed percentiles of the right and left Sylvian fissure angles indicated that median, 10^th and 90^th smoothed percentiles were closest and almost the same for the GA-based references between 18 and 28 weeks and for the HC-based references between 14 and 24 cm. The intraclass correlation coefficient of the right and left Sylvian fissure angle measurements between the two sonographers was excellent at 0.993 (95% CI, 0.988-0.996) and 0.991 (95% CI, 0.985-0.995), respectively. On Bland-Altman analysis, the mean difference between the two sonographers in right Sylvian fissure angle measurement was 0.4° (95% CI, -10.2 to 10.1°) and in left Sylvian fissure angle it was 1.0° (95% CI, -9.6 to 11.6°).

CONCLUSIONS

Assessment of the Sylvian fissure angles is highly reproducible. Sylvian fissure angle reference charts can serve as a screening tool for malformations of cortical development, guiding subsequent follow-up and referral for fetal brain magnetic resonance imaging and/or assessment by an expert neurosonologist. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Maternal hemodynamics in screen-positive and screen-negative women of the ASPRE trial

OBJECTIVE

To compare maternal hemodynamics and perinatal outcome, in pregnancies that do not develop pre-eclampsia (PE) or deliver a small-for-gestational-age (SGA) neonate, between those identified at 11-13 weeks' gestation as being screen positive or negative for preterm PE, by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index, serum placental growth factor and pregnancy associated plasma protein-A.

METHODS

This was a prospective longitudinal cohort study of maternal cardiovascular function, assessed using a bioreactance method, in women undergoing first-trimester screening for PE. Maternal hemodynamics and perinatal outcome were compared between screen-positive and screen-negative women who did not have a medical comorbidity, did not develop PE or pregnancy-induced hypertension and delivered at term a live neonate with birth weight between the 5^th and 95^th percentiles. A multilevel linear mixed-effects model was used to compare the repeated measures of cardiac variables, controlling for maternal characteristics.

RESULTS

The screen-negative group (n = 926) had normal cardiac function changes across gestation, whereas the screen-positive group (n = 170) demonstrated static or reduced cardiac output and stroke volume and higher mean arterial pressure and peripheral vascular resistance with advancing gestation. In the screen-positive group, compared with screen-negative women, birth-weight Z-score was shifted toward lower values, with prevalence of delivery of a neonate below the 35^th , 30^th or 25^th percentile being about 70% higher, and the rate of operative delivery for fetal distress in labor also being higher.

CONCLUSION

Women who were screen positive for impaired placentation, even though they did not develop PE or deliver a SGA neonate, had pathological cardiac adaptation in pregnancy and increased risk of adverse perinatal outcome. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Transverse technique: complementary approach to measurement of first-trimester uterine artery Doppler

OBJECTIVES

To define a protocol for the first-trimester assessment of uterine artery pulsatility index (UtA-PI) using the new transverse technique, to evaluate UtA-PI measured using the transverse approach vs that obtained using the conventional sagittal approach and to determine if accelerated onsite training (in both methods) of inexperienced sonographers can achieve reproducible UtA-PI measurements comparable with those obtained by an experienced sonographer.

METHODS

This was a prospective observational study of women with a singleton pregnancy attending for routine combined first-trimester screening at 11 to 13 + 6 weeks' gestation. The study consisted of two parts, each conducted at a different center (Part 1 in Calgary, Canada and Part 2 in Hong Kong). In Part 1, UtA-PI measurements were performed using the transverse and sagittal techniques by four sonographers trained in both methods, in 10 cases each, and measurement indices (PI), time required and subjective difficulty in obtaining satisfactory measurements were compared. The one sample t-test and Wilcoxon signed rank test were used when appropriate. Bland-Altman plots were used to assess measurement agreement, and intraclass correlation coefficient (ICC) was used to evaluate measurement reliability. A target plot was used to assess measures of central tendency and dispersion. In Part 2, one experienced and three inexperienced sonographers prospectively measured UtA-PI using both approaches in 42 and 35 women, respectively. Inexperienced sonographers underwent accelerated onsite training by the experienced sonographer. Measurement approach and sonographer order were on a random basis. ICC, Bland-Altman and Passing-Bablok analyses were performed to assess measurement agreement and reliability and effect of accelerated training.

RESULTS

In Part 1, no difference was observed between the two techniques in mean time to acquire the measurements (118 s for sagittal vs 106 s for transverse; P = 0.38). The four sonographers reported that the transverse technique was subjectively easier to perform (P = 0.04). Bias and ICC for mean UtA-PI between sagittal and transverse measurements were -0.05 (95% limits of agreement, -0.48 to 0.37) and 0.94, respectively. Measurements obtained using the transverse technique after correcting for gestational age were significantly closer to the expected distribution than those obtained using the sagittal technique. In Part 2, there were no significant differences in median UtA-PI measured using the different approaches for both experienced and inexperienced sonographers (P > 0.05 for all sonographers). Mean UtA-PI measurement reliability between approaches was high for the experienced (ICC = 0.92) and inexperienced (ICC > 0.80) sonographers. UtA-PI measurement approaches did not deviate from linearity, while bias ranged from -0.10 to 0.07. The median time required was similar between the techniques (56.1 s for sagittal vs 49.3 s for transverse; P = 0.054).

CONCLUSIONS

This novel transverse approach for the measurement of UtA-PI in the first trimester appears to be comparable with the sagittal approach in terms of reliability, reproducibility and time required, and may be easier to perform. Providing accelerated onsite training can be helpful for improving the reliability of UtA-PI measurements and could potentially facilitate the broad implementation of first-trimester pre-eclampsia screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Maternal hemodynamics, fetal biometry and Doppler indices in pregnancies followed up for suspected fetal growth restriction

OBJECTIVES

To assess whether, in a cohort of patients with a small-for-gestational-age (SGA) fetus with estimated fetal weight ≤ 10^th percentile, maternal hemodynamics, fetal biometry and Doppler indices at presentation can predict the subsequent development of an abnormal fetal Doppler index or delivery of a baby with birth weight < 3^rd percentile.

METHODS

This was a prospective observational cohort study conducted at a specialist clinic for the management of pregnancies with a SGA fetus at King's College Hospital, London, UK. The study population comprised 86 singleton pregnancies with a SGA fetus, presenting at a median gestational age of 32 (range, 26-35) weeks. We measured maternal cardiac function using a non-invasive transthoracic bioreactance monitor, as well as mean arterial pressure, fetal biometry, and umbilical artery (UA), fetal middle cerebral artery (MCA) and uterine artery (UtA) pulsatility indices (PI), and the deepest vertical pool of amniotic fluid. Z-scores of these variables were calculated based on reported reference ranges and the values were compared between pregnancies with evidence of an abnormal fetal Doppler index at presentation (Group 1), those that had developed an abnormal Doppler index at a subsequent visit (Group 2) and those that did not develop an abnormal Doppler index throughout pregnancy (Group 3). Abnormal fetal Doppler was defined as UA-PI > 95^th percentile and/or MCA-PI < 5^th percentile. Differences in measured variables at presentation were also compared between pregnancies delivering a baby with birth weight < 3^rd percentile and those delivering a baby with birth weight ≥ 3^rd percentile. Multivariate logistic regression analysis was used to determine significant predictors of birth weight < 3^rd percentile and evolution from normal to abnormal fetal Doppler.

RESULTS

In the study population, 14 (16%) cases were in Group 1, 19 (22%) in Group 2 and 53 (62%) in Group 3. Birth weight was < 3^rd percentile in 39 (45%) cases and ≥ 3^rd percentile in 47 (55%). There was decreased cardiac output and stroke volume and increased peripheral vascular resistance compared with a normal population, and the deviations from normal were most marked in Group 1. Pregnancies with birth weight < 3^rd percentile, compared with those with birth weight ≥ 3^rd percentile, had greater deviations from normal in fetal biometry, maternal cardiac output, stroke volume, heart rate, peripheral vascular resistance and UtA-PI. Multivariate logistic regression analysis demonstrated that, in the prediction of birth weight < 3^rd percentile, maternal hemodynamic profile provided significant improvement to the prediction provided by maternal demographics, fetal biometry, UtA-PI, UA-PI and MCA-PI (difference between areas under receiver-operating characteristics curves, 0.18 (95% CI, 0.06-0.29); P = 0.002). In contrast, there was no significant independent contribution from maternal hemodynamics in the prediction of the subsequent development of abnormal fetal Doppler.

CONCLUSIONS

In pregnancies with a SGA fetus, there is decreased maternal cardiac output and stroke volume and increased peripheral vascular resistance, and the deviations from normal are most marked in cases of redistribution in the fetal circulation and reduced amniotic fluid volume. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

OBJECTIVE

To examine the performance of screening for early, preterm and term pre-eclampsia (PE) at 11-13 weeks' gestation by maternal factors and combinations of mean arterial pressure (MAP), uterine artery (UtA) pulsatility index (PI), serum placental growth factor (PlGF) and serum pregnancy-associated plasma protein-A (PAPP-A).

METHODS

The data for this study were derived from three previously reported prospective non-intervention screening studies at 11 + 0 to 13 + 6 weeks' gestation in a combined total of 61 174 singleton pregnancies, including 1770 (2.9%) that developed PE. Bayes' theorem was used to combine the prior distribution of gestational age at delivery with PE, obtained from maternal characteristics, with various combinations of biomarker multiples of the median (MoM) values to derive patient-specific risks of delivery with PE at < 37 weeks' gestation. The performance of such screening was estimated.

RESULTS

In pregnancies that developed PE, compared to those without PE, the MoM values of UtA-PI and MAP were increased and those of PAPP-A and PlGF were decreased, and the deviation from normal was greater for early than late PE for all four biomarkers. Combined screening by maternal factors, UtA-PI, MAP and PlGF predicted 90% of early PE, 75% of preterm PE and 41% of term PE, at a screen-positive rate of 10%; inclusion of PAPP-A did not improve the performance of screening. The performance of screening depended on the racial origin of the women; on screening by a combination of maternal factors, MAP, UtA-PI and PlGF and using a risk cut-off of 1 in 100 for PE at < 37 weeks in Caucasian women, the screen-positive rate was 10% and detection rates for early, preterm and term PE were 88%, 69% and 40%, respectively. With the same method of screening and risk cut-off in women of Afro-Caribbean racial origin, the screen-positive rate was 34% and detection rates for early, preterm and term PE were 100%, 92% and 75%, respectively.

CONCLUSION

Screening by maternal factors and biomarkers at 11-13 weeks' gestation can identify a high proportion of pregnancies that develop early and preterm PE. © 2018 Crown copyright. Ultrasound in Obstetrics & Gynecology © 2018 ISUOG.

Prediction and prevention of small-for-gestational-age neonates: evidence from SPREE and ASPRE

OBJECTIVES

To examine the effect of first-trimester screening for pre-eclampsia (PE) on the prediction of delivering a small-for-gestational-age (SGA) neonate and the effect of prophylactic use of aspirin on the prevention of SGA.

METHODS

The data for this study were derived from two multicenter studies. In SPREE, we investigated the performance of screening for PE by a combination of maternal characteristics and biomarkers at 11-13 weeks' gestation. In ASPRE, women with a singleton pregnancy identified by combined screening as being at high risk for preterm PE (> 1 in 100) participated in a trial of aspirin (150 mg/day from 11-14 until 36 weeks' gestation) compared to placebo. In this study, we used the data from the ASPRE trial to estimate the effect of aspirin on the incidence of SGA with birth weight < 10^th , < 5^th and < 3^rd percentile for gestational age. We also used the data from SPREE to estimate the proportion of SGA in the pregnancies with a risk for preterm PE of > 1 in 100.

RESULTS

In SPREE, screening for preterm PE by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index and serum placental growth factor identified a high-risk group that contained about 46% of SGA neonates < 10^th percentile born at < 37 weeks' gestation (preterm) and 56% of those born at < 32 weeks (early); the overall screen-positive rate was 12.2% (2014 of 16 451 pregnancies). In the ASPRE trial, use of aspirin reduced the overall incidence of SGA < 10^th percentile by about 40% in babies born at < 37 weeks' gestation and by about 70% in babies born at < 32 weeks; in babies born at ≥ 37 weeks, aspirin did not have a significant effect on incidence of SGA. The aspirin-related decrease in incidence of SGA was mainly due to its incidence decreasing in pregnancies with PE, for which the decrease was about 70% in babies born at < 37 weeks' gestation and about 90% in babies born at < 32 weeks. On the basis of these results, it was estimated that first-trimester screening for preterm PE and use of aspirin in the high-risk group would potentially reduce the incidence of preterm and early SGA by about 20% and 40%, respectively.

CONCLUSION

First-trimester screening for PE by the combined test identifies a high proportion of cases of preterm SGA that can be prevented by the prophylactic use of aspirin. © 2018 Crown copyright. Ultrasound in Obstetrics & Gynecology © 2018 ISUOG.

ASPRE trial: incidence of preterm pre-eclampsia in patients fulfilling ACOG and NICE criteria according to risk by FMF algorithm

OBJECTIVE

To report the incidence of preterm pre-eclampsia (PE) in women who are screen positive according to the criteria of the National Institute for Health and Care Excellence (NICE) and the American College of Obstetricians and Gynecologists (ACOG), and compare the incidence with that in those who are screen positive or screen negative by The Fetal Medicine Foundation (FMF) algorithm.

METHODS

This was a secondary analysis of data from the ASPRE study. The study population consisted of women with singleton pregnancy who underwent prospective screening for preterm PE by means of the FMF algorithm, which combines maternal factors and biomarkers at 11-13 weeks' gestation. The incidence of preterm PE in women fulfilling the NICE and ACOG criteria was estimated; in these patients the incidence of preterm PE was then calculated in those who were screen negative relative to those who were screen positive by the FMF algorithm.

RESULTS

A total of 34 573 women with singleton pregnancy delivering at ≥ 24 weeks' gestation underwent prospective screening for preterm PE, of which 239 (0.7%) cases developed preterm PE. At least one of the ACOG criteria was fulfilled in 22 287 (64.5%) pregnancies and the incidence of preterm PE was 0.97% (95% CI, 0.85-1.11%); in the subgroup that was screen positive by the FMF algorithm the incidence of preterm PE was 4.80% (95% CI, 4.14-5.55%), and in those that were screen negative it was 0.25% (95% CI, 0.18-0.33%), with a relative incidence in FMF screen negative to FMF screen positive of 0.051 (95% CI, 0.037-0.071). In 1392 (4.0%) pregnancies, at least one of the NICE high-risk criteria was fulfilled, and in this group the incidence of preterm PE was 5.17% (95% CI, 4.13-6.46%); in the subgroups of screen positive and screen negative by the FMF algorithm, the incidence of preterm PE was 8.71% (95% CI, 6.93-10.89%) and 0.65% (95% CI, 0.25-1.67%), respectively, and the relative incidence was 0.075 (95% CI, 0.028-0.205). In 2360 (6.8%) pregnancies fulfilling at least two of the NICE moderate-risk criteria, the incidence of preterm PE was 1.74% (95% CI, 1.28-2.35%); in the subgroups of screen positive and screen negative by the FMF algorithm the incidence was 4.91% (95% CI, 3.54-6.79%) and 0.42% (95% CI, 0.20-0.86%), respectively, and the relative incidence was 0.085 (95% CI, 0.038-0.192).

CONCLUSION

In women who are screen positive for preterm PE by the ACOG or NICE criteria but screen negative by the FMF algorithm, the risk of preterm PE is reduced to within or below background levels. The results provide further evidence to support the personalized risk-based screening method that combines maternal factors and biomarkers. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Effect of change in posture on maternal functional hemodynamics at 35-37 weeks' gestation

OBJECTIVES

To evaluate the effect of posture change from the supine to the sitting position and before and after passive leg raising on maternal functional hemodynamics in pregnant women at 35-37 weeks' gestation, and to compare the changes in pregnancies that subsequently developed pre-eclampsia (PE) or gestational hypertension (GH) with those that remained normotensive.

METHODS

In 2764 singleton pregnancies at 35-37 weeks' gestation, maternal cardiovascular parameters were measured using an automated non-invasive cardiac monitor. The hemodynamic response to a change from the supine to the sitting position and before and after passive leg raising in the left lateral position was examined and compared between women who subsequently developed PE or GH and those who remained normotensive.

RESULTS

In normotensive singleton pregnancies at 35-37 weeks' gestation, both change from the supine to the sitting position and passive leg raising were associated with an increase in cardiac index and stroke volume index and a decrease in total peripheral resistance index; there was a small increase in mean arterial pressure with both postural changes and a slight decrease in heart rate with passive leg raising. In pregnancies that subsequently developed PE or GH, compared with normotensive pregnancies, cardiac index and stroke volume index were lower and total peripheral resistance index was higher. In general, change from the supine to the sitting position and passive leg raising were associated with similar but less marked changes in cardiovascular parameters as in normotensive pregnancies.

CONCLUSIONS

Paradoxically, in late third-trimester normal pregnancy, both change from the supine to a sitting position and passive leg raising may result in an increase in preload with a consequent increase in cardiac and stroke volume indices and a decrease in total peripheral resistance index. In pregnancies that develop PE or GH, the effects of postural change on cardiovascular parameters are similar but less marked than in normotensive pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Accuracy of competing-risks model in screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

OBJECTIVE

To examine the diagnostic accuracy of a previously developed model for prediction of pre-eclampsia (PE) by a combination of maternal factors and biomarkers at 11-13 weeks' gestation.

METHODS

This was a prospective first-trimester multicenter study of screening for PE in 8775 singleton pregnancies. A previously published algorithm was used for the calculation of patient-specific risk of PE in each individual. The detection rates (DRs) and false-positive rates (FPRs) for delivery with PE < 32, < 37 and ≥ 37 weeks were estimated and compared with those for the dataset used for development of the algorithm.

RESULTS

In the study population, 239 (2.7%) cases developed PE, of which 17 (0.2%), 59 (0.7%) and 180 (2.1%) developed PE < 32, < 37 and ≥ 37 weeks, respectively. With combined screening by maternal factors, mean arterial pressure, uterine artery pulsatility index and serum placental growth factor, the DR was 100% (95% CI, 80-100%) for PE < 32 weeks, 75% (95% CI, 62-85%) for PE < 37 weeks and 43% (95% CI, 35-50%) for PE ≥ 37 weeks, at a 10% FPR. These DRs were similar to the estimated rates for the dataset used for development of the model: 89% (95% CI, 79-96%) for PE < 32 weeks, 75% (95% CI, 70-80%) for PE < 37 weeks and 47% (95% CI, 44-51%) for PE ≥ 37 weeks.

CONCLUSION

Assessment of a combination of maternal factors and biomarkers at 11-13 weeks provides effective first-trimester screening for preterm PE. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Multicenter screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation: comparison with NICE guidelines and ACOG recommendations

OBJECTIVE

To compare the performance of screening for pre-eclampsia (PE) based on risk factors from medical history, as recommended by NICE and ACOG, with the method proposed by The Fetal Medicine Foundation (FMF), which uses Bayes' theorem to combine the a-priori risk from maternal factors, derived by a multivariable logistic model, with the results of various combinations of biophysical and biochemical measurements.

METHODS

This was a prospective multicenter study of screening for PE in 8775 singleton pregnancies at 11-13 weeks' gestation. A previously published FMF algorithm was used for the calculation of patient-specific risk of PE in each individual. The detection rates (DRs) and false-positive rates (FPRs) for delivery with PE < 32, < 37 and ≥ 37 weeks were estimated and compared with those derived from application of NICE guidelines and ACOG recommendations. According to NICE, all high-risk pregnancies should be offered low-dose aspirin. According to ACOG, use of aspirin should be reserved for women with a history of PE in at least two previous pregnancies or PE requiring delivery < 34 weeks' gestation.

RESULTS

In the study population, 239 (2.7%) cases developed PE, of which 17 (0.2%), 59 (0.7%) and 180 (2.1%) developed PE < 32, < 37 and ≥ 37 weeks, respectively. Screening with use of the FMF algorithm based on a combination of maternal factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) and serum placental growth factor (PlGF) detected 100% (95% CI, 80-100%) of PE < 32 weeks, 75% (95% CI, 62-85%) of PE < 37 weeks and 43% (95% CI, 35-50%) of PE ≥ 37 weeks, at a 10.0% FPR. Screening with use of NICE guidelines detected 41% (95% CI, 18-67%) of PE < 32 weeks, 39% (95% CI, 27-53%) of PE < 37 weeks and 34% (95% CI, 27-41%) of PE ≥ 37 weeks, at 10.2% FPR. Screening with use of ACOG recommendations detected 94% (95% CI, 71-100%) of PE < 32 weeks, 90% (95% CI, 79-96%) of PE < 37 weeks and 89% (95% CI, 84-94%) of PE ≥ 37 weeks, at 64.2% FPR. Screening based on the ACOG recommendations for use of aspirin detected 6% (95% CI, 1-27%) of PE < 32 weeks, 5% (95% CI, 2-14%) of PE < 37 weeks and 2% (95% CI, 0.3-5%) of PE ≥ 37 weeks, at 0.2% FPR.

CONCLUSION

Performance of screening for PE at 11-13 weeks' gestation by the FMF algorithm using a combination of maternal factors, MAP, UtA-PI and PlGF, is by far superior to the methods recommended by NICE and ACOG. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac function at 35-37 weeks' gestation: relationship with birth weight

OBJECTIVE

To evaluate the relationship between maternal cardiovascular parameters and neonatal birth weight and examine the potential value of these parameters in improving the prediction of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) neonates provided by maternal characteristics and medical history.

METHODS

In 2835 singleton pregnancies maternal characteristics and medical history were recorded and maternal cardiovascular parameters were measured. The observed measurements of cardiovascular parameters were expressed as multiples of the normal median (MoM) values after adjustment for those characteristics found to provide a substantial contribution to their measurement. Regression analysis was used to determine the significance of association between the normalized values of the cardiovascular parameters with birth-weight Z-score. Multivariable logistic regression analysis was then used to determine if the maternal factors, fetal biometry and maternal cardiovascular parameters had a significant contribution to predicting SGA and LGA neonates. The performance of screening was determined by the area under receiver-operating characteristics curves (AUC).

RESULTS

In the study population there were significant positive associations between maternal cardiac output and heart rate with neonatal birth-weight Z-score, and significant negative associations between total peripheral resistance and mean arterial pressure (MAP) with neonatal birth-weight Z-score. In pregnancies delivering SGA neonates (n = 249 (8.8%)), cardiac output and heart rate were lower and total peripheral resistance and MAP were higher, whereas in pregnancies delivering LGA neonates (n = 292 (10.3%)) cardiac output and heart rate were higher and total peripheral resistance and MAP were lower. The performance of screening for delivery of SGA neonates achieved by maternal characteristics and fetal biometry was not improved by the measurement of maternal cardiovascular parameters. There was a small but significant improvement in the performance of screening for delivery of LGA neonates by maternal factors and fetal biometry with the addition of maternal heart rate (comparison of AUC, P = 0.0095).

CONCLUSIONS

There are significant associations between maternal cardiac output, heart rate, total peripheral resistance and MAP and neonatal birth-weight Z-score; such findings reflect the close relationship between maternal cardiac function and fetal demands. However, assessment of these parameters at 35-37 weeks' gestation is unlikely to improve substantially the performance of screening for SGA or LGA neonates provided by a combination of maternal factors and fetal biometry. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiovascular function at 35-37 weeks' gestation: relation to maternal characteristics

OBJECTIVE

To examine the possible effects of maternal characteristics and obstetric and medical history on maternal cardiovascular parameters at 35-37 weeks' gestation.

METHODS

In 3013 singleton pregnancies at 35-37 weeks, maternal characteristics and medical history were recorded; uterine artery pulsatility index, mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable regression analysis was used to determine significant predictors of the cardiovascular parameters among gestational age (GA), maternal characteristics and medical history.

RESULTS

Multivariable regression analysis demonstrated that significant independent prediction of log₁₀ cardiac output and log₁₀ cardiac power was provided by GA, maternal age, weight, weight gain from the first trimester, height, racial origin, smoking, assisted conception and previous neonatal birth-weight Z-score in parous women. For log₁₀ total peripheral resistance, significant prediction was provided by GA, maternal age, height, racial origin, chronic hypertension, diabetes mellitus, assisted conception, previous neonatal birth-weight Z-score and prior pre-eclampsia (PE) in parous women. For log₁₀ stroke volume, significant prediction was provided by maternal age, height, racial origin, smoking, chronic hypertension and diabetes mellitus. For heart rate, significant prediction was provided by GA, weight, weight gain, height, racial origin, chronic hypertension, previous neonatal birth-weight Z-score and prior PE in parous women. For log₁₀ MAP, significant prediction was provided by maternal weight, racial origin, family history of PE, chronic hypertension and diabetes mellitus. For log₁₀ thoracic fluid capacity, significant prediction was provided by GA, maternal age, weight, height, racial origin and systemic lupus erythematosus or antiphospholipid syndrome. For log₁₀ ventricular ejection time, significant prediction was provided by GA, weight, height and racial origin.

CONCLUSION

Maternal cardiovascular parameters are affected by maternal characteristics and medical and obstetric history, and they should therefore be converted into multiples of the normal median adjusted for significant independent predictors before their inclusion in combined screening for PE. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac function at 35-37 weeks' gestation: prediction of pre-eclampsia and gestational hypertension

OBJECTIVE

To investigate the potential value of combining maternal factors with multiples of the normal median values of maternal cardiovascular parameters at 35-37 weeks' gestation in the prediction of pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

In 2764 singleton pregnancies maternal characteristics and medical history were recorded; uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable logistic regression analysis was then used to determine if the maternal factors and maternal cardiovascular parameters made a significant contribution to predicting PE and GH. The performance of screening was determined by the area under receiver-operating characteristics curves.

RESULTS

In pregnancies that subsequently delivered with PE or GH, total peripheral resistance and MAP were higher and maternal cardiac output was lower, mainly owing to a decrease in heart rate in PE and a decrease in stroke volume in GH. The increases in total peripheral resistance and MAP were inversely related to gestational age at delivery. The performance of screening for PE and GH achieved by maternal characteristics and medical history was improved by the inclusion of MAP, but not by UtA-PI or maternal cardiovascular parameters.

CONCLUSIONS

In women developing term PE total peripheral resistance and MAP are increased and maternal cardiac output is reduced. However, assessment of maternal cardiac function at 35-37 weeks' gestation is unlikely to improve the performance of screening for PE provided by maternal factors and MAP alone. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Prediction of large-for-gestational-age neonates: screening by maternal factors and biomarkers in the three trimesters of pregnancy

OBJECTIVE

To develop a model based on maternal characteristics and medical history (maternal factors) for the prediction of delivery of large-for-gestational-age (LGA) neonates, and to examine the potential value of first-, second- and third-trimester fetal biometry and biomarkers in improving such a model.

METHODS

This was a screening study in 76 300, 54 999, 25 727 and 6181 singleton pregnancies at 11-13, 19-24, 30-34 and 35-37 weeks' gestation, respectively. The a-priori risk for LGA with birth weight > 95(th) percentile (LGA > 95(th) ) was calculated using multivariable logistic regression analysis to determine which of the maternal factors had a significant contribution. Regression analysis was then used to determine whether screening by a combination of maternal factors, fetal biometry and various biophysical and biochemical markers had significant contribution in predicting delivery of LGA neonates.

RESULTS

The likelihood of LGA > 95(th) increased with increasing maternal weight and height and was lower in women of Afro-Caribbean and South Asian racial origins, in cigarette smokers and in nulliparous women. The risk was higher in women with pre-existing diabetes mellitus Type I and lower in those with chronic hypertension. In parous women, the risk increased with birth-weight Z-score in previous pregnancy and prior history of gestational diabetes and decreased with interpregnancy interval. Screening by maternal factors at 11-13 weeks predicted 32%, 44% and 60% of LGA > 95(th) at false-positive rates (FPRs) of 5%, 10% and 20%, respectively. With the addition of fetal biometry, the detection rates improved to 37%, 51% and 68% at 19-24 weeks, 50%, 65% and 81% at 30-34 weeks and 60%, 73% and 85% at 35-37 weeks at FPRs of 5%, 10% and 20%, respectively. The addition of biomarkers did not improve the detection rates achieved when screening by a combination of maternal factors and fetal biometry.

CONCLUSION

Combined screening by maternal factors and fetal biometry can predict a high proportion of pregnancies that will deliver LGA neonates. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Clinical implementation of routine screening for fetal trisomies in the UK NHS: cell-free DNA test contingent on results from first-trimester combined test

OBJECTIVES

Cell-free DNA (cfDNA) analysis of maternal blood for detection of trisomies 21, 18 and 13 is superior to other methods of screening but is expensive. One strategy to maximize performance at reduced cost is to offer cfDNA testing contingent on the results of the first-trimester combined test that is used currently. The objectives of this study were to report the feasibility of implementing such screening, to examine the factors affecting patient decisions concerning their options for screening and decisions on the management of affected pregnancies and to report the prenatal diagnosis of fetal trisomies and outcome of affected pregnancies following the introduction of contingent screening.

METHODS

We examined routine clinical implementation of contingent screening in 11,692 singleton pregnancies in two National Health Service (NHS) hospitals in the UK. Women with a risk ≥ 1 in 100 (high-risk group) were offered options of invasive testing, cfDNA testing or no further testing, and those with a risk between 1 in 101 and 1 in 2500 (intermediate-risk group) were offered cfDNA testing or no further testing. The trisomic status of the pregnancies was determined by prenatal or postnatal karyotyping or by examination of the neonates.

RESULTS

In the study population of 11,692 pregnancies, there were 47 cases of trisomy 21 and 28 of trisomies 18 or 13. Screening with the combined test followed by invasive testing for all patients in the high-risk group potentially could have detected 87% of trisomy 21 and 93% of trisomies 18 or 13, at a false-positive rate of 3.4%; the respective values for cfDNA testing in the high- and intermediate-risk groups were 98%, 82% and 0.25%. However, in the high-risk group, 38% of women chose invasive testing and 60% chose cfDNA testing; in the intermediate-risk group 92% opted for cfDNA testing. A prenatal diagnosis was made in 43 (91.5%) pregnancies with trisomy 21 and all pregnancies with trisomies 18 or 13. In many affected pregnancies the parents chose to avoid testing or termination and 32% of pregnancies with trisomy 21 resulted in live births.

CONCLUSIONS

Screening for fetal trisomies by cfDNA analysis of maternal blood, contingent on the results of the combined test, can be implemented easily in routine clinical practice. In the high-risk group from the combined test, most but not all women chose cfDNA testing rather than invasive testing. Performance of screening for trisomy 21 was superior by the cfDNA test than by the combined test. However, prenatal detection of trisomies and pregnancy outcome depend not only on performance of screening tests but also on parental choice.

Prediction of small-for-gestational-age neonates: screening by biophysical and biochemical markers at 30-34 weeks

OBJECTIVE

To investigate the potential value of combined screening by maternal characteristics and medical history (maternal factors), estimated fetal weight (EFW), uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP) and serum levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) at 30-34 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE).

METHODS

This was a screening study in 9472 singleton pregnancies at 30-34 weeks' gestation, comprising 469 that delivered SGA neonates and 9003 cases unaffected by SGA, PE or gestational hypertension. Multivariable logistic regression analysis was used to determine if UtA-PI, MAP and serum PlGF or sFlt-1, individually or in combination, improved the prediction of SGA neonates provided from screening by maternal factors and EFW.

RESULTS

Compared to the normal group, mean log10 multiples of the median (MoM) values of UtA-PI, MAP and serum sFlt-1 were significantly higher and log10 MoM PlGF was lower in the SGA group. Multivariable logistic regression analysis demonstrated that in the prediction of SGA neonates with a birth weight < 5(th) percentile, delivering < 5 weeks and ≥ 5 weeks after assessment, there were significant independent contributions from maternal factors, EFW, UtA-PI, MAP, and serum PlGF and sFlt-1, but the best performance was provided by a combination of maternal factors, EFW, UtA-PI, MAP and serum PlGF, excluding sFlt-1. Combined screening predicted, at a 10% false-positive rate, 89%, 94%, 96% of SGA neonates delivering at 32-36 weeks' gestation with birth weight < 10(th) , < 5(th) and < 3(rd) percentiles, respectively; the respective detection rates of combined screening for SGA neonates delivering ≥ 37 weeks were 57%, 65% and 72%.

CONCLUSION

Combined screening by maternal factors and biophysical and biochemical markers at 30-34 weeks' gestation could identify a high proportion of pregnancies that will deliver SGA neonates.

Prediction of small-for-gestational-age neonates: screening by biophysical and biochemical markers at 19-24 weeks

OBJECTIVE

To investigate the value of combined screening by maternal characteristics and medical history, fetal biometry and biophysical and biochemical markers at 19-24 weeks' gestation, for prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE), and examine the potential value of such assessment in deciding whether the third-trimester scan should be at 32 and/or 36 weeks' gestation.

METHODS

This was a screening study in 7816 singleton pregnancies, including 389 (5.0%) that delivered SGA neonates with birth weight < 5(th) percentile (SGA < 5(th) ), in the absence of PE. Multivariable logistic regression analysis was used to determine if screening by a combination of maternal factors, fetal biometry, uterine artery pulsatility index (UtA-PI) and maternal serum concentrations of placental growth factor (PlGF) and α-fetoprotein (AFP) had significant contribution in predicting SGA neonates. A model was developed for selecting the gestational age for third-trimester assessment, at 32 and/or 36 weeks, based on the results of screening at 19-24 weeks.

RESULTS

Significant independent contributions to the prediction of SGA < 5(th) were provided by maternal factors, fetal biometry, UtA-PI and serum PlGF and AFP. The detection rate (DR) of such combined screening at 19-24 weeks was 100%, 78% and 42% for SGA < 5(th) delivering < 32, at 32-36 and ≥ 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. In a hypothetical model, it was estimated that if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th) , it would be necessary to select 11% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 44% to be reassessed at 36 weeks; 57% would not require a third-trimester scan.

CONCLUSION

Prenatal prediction of a high proportion of SGA neonates necessitates the undertaking of screening in the third trimester of pregnancy, in addition to assessment in the second trimester, and the timing of such screening, at 32 and/or 36 weeks, should be contingent on the results of the assessment at 19-24 weeks.

Prediction of small-for-gestational-age neonates: screening by uterine artery Doppler and mean arterial pressure at 19-24 weeks

OBJECTIVE

To investigate the potential value of uterine artery (UtA) pulsatility index (PI) and mean arterial pressure (MAP) at 19-24 weeks' gestation, in combination with maternal characteristics and medical history and fetal biometry in the prediction of delivery of small-for-gestational-age (SGA) neonates in the absence of pre-eclampsia (PE) and to examine the potential value of such assessment in deciding whether the third-trimester scan should be performed at 32 and/or 36 weeks' gestation.

METHODS

This was a screening study in 63 975 singleton pregnancies, including 3702 (5.8%) that delivered SGA neonates with birth weight < 5(th) percentile (SGA < 5(th) ) in the absence of PE. Multivariable logistic regression analysis was used to determine if screening by a combination of maternal factors, fetal head circumference (HC), abdominal circumference (AC), femur length (FL), UtA-PI and MAP had significant contribution in predicting SGA neonates. A model was developed to select gestational age for the third-trimester assessment, at 32 and/or 36 weeks, based on the results of screening at 19-24 weeks.

RESULTS

The detection rates (DRs) of combined screening by maternal factors, fetal biometry and UtA-PI at 19-24 weeks were 90%, 68% and 44% for SGA < 5(th) delivering < 32, 32-36 and ≥ 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. The performance of screening was not improved by the addition of MAP. The DR of SGA < 5(th) delivering at 32-36 weeks improved from 68% to 90% with screening at 32 rather than at 19-24 weeks. Similarly, the DR of SGA < 5(th) delivering ≥ 37 weeks improved from 44% with screening at 19-24 weeks to 59% and 76% when screening at 32 and 36 weeks, respectively. In a hypothetical model, it was estimated that if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th) , it would be necessary to select 17% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 38% to be reassessed at 36 weeks; 62% would not require a third-trimester scan.

CONCLUSION

Prenatal prediction of a high proportion of SGA neonates necessitates the undertaking of screening in the third trimester of pregnancy in addition to assessment in the second trimester, and the timing of such screening, at 32 and/or 36 weeks, should be contingent on the results of the assessment at 19-24 weeks.

The effect of gestational age and cervical length measurements in the prediction of spontaneous preterm birth in twin pregnancies: an individual patient level meta-analysis

OBJECTIVE

To assess the effect of gestational age (GA) and cervical length (CL) measurements at transvaginal ultrasound (TVUS) in the prediction of preterm birth in twin pregnancy.

DESIGN

Individual patient data (IPD) meta-analysis.

SETTING

International multicentre study.

POPULATION

Asymptomatic twin pregnancy.

METHODS

MEDLINE and EMBASE searches were performed and IPD obtained from authors of relevant studies. Multinomial logistic regression analysis determined probabilities for birth at ≤28(+0) , 28(+1) to 32(+0) , 32(+1) to 36(+0) , and ≥36(+1) weeks as a function of GA at screening and CL measurements.

MAIN OUTCOME MEASURES

Predicted probabilities for preterm birth at ≤28(+0) , 28(+1) to 32(+0) , and 32(+1) to 36(+0) .

RESULTS

A total of 6188 CL measurements were performed on 4409 twin pregnancies in 12 studies. Both GA at screening and CL had a significant and non-linear effect on GA at birth. The best prediction of birth at ≤28(+0) weeks was provided by screening at ≤18(+0) weeks (P < 0.001), whereas the best prediction of birth between 28(+1) and 36(+0) weeks was provided by screening at ≥24(+0) weeks (P < 0.001). Negative prediction value of 100% for birth at ≤28(+0) weeks is achieved at CL 65 mm and 43 mm at ultrasound GA at ≤18(+0) weeks and at 22(+1) to 24(+0) weeks, respectively.

CONCLUSION

In twin pregnancies, prediction of preterm birth depends on both CL and the GA at screening. When CL is <30 mm, screening at ≤18(+0) weeks is most predictive for birth at ≤28(+0) weeks. Later screening at >22(+0) weeks is most predictive of delivery at 28(+1) to 36(+0) weeks. In twins, we recommend CL screening in twins to commence from ≤18(+0) weeks.

TWEETABLE ABSTRACT

An individual patient meta-analysis assessing gestation and CL in the prediction of preterm birth in twins.

Prediction of small-for-gestational-age neonates: screening by maternal serum biochemical markers at 19-24 weeks

OBJECTIVE

To investigate the value of maternal serum concentrations of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (β-hCG) and α-fetoprotein (AFP) at 19-24 weeks' gestation, in combination with maternal factors and fetal biometry, in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE) and examine the potential value of such assessment in deciding whether the third-trimester scan should be performed at 32 and/or 36 weeks' gestation.

METHODS

This was a screening study in 9715 singleton pregnancies, including 481 (5.0%) that delivered SGA neonates with birth weight < 5(th) percentile (SGA < 5(th) ), in the absence of PE. Multivariable logistic regression analysis was used to determine if screening by a combination of maternal factors, Z-scores of fetal head circumference, abdominal circumference and femur length, and log10 multiples of the median (MoM) values of PlGF, sFlt-1, PAPP-A, free β-hCG or AFP had a significant contribution to the prediction of SGA neonates. A model was developed in selecting the gestational age for third-trimester assessment, at 32 and/or 36 weeks, based on the results of screening at 19-24 weeks.

RESULTS

Compared to the normal group, the mean log10 MoM value of PlGF was lower, AFP was higher and sFlt-1, PAPP-A and free β-hCG were not significantly different in the SGA < 5(th) group that delivered < 37 weeks. The detection rate (DR) of combined screening by maternal factors, fetal biometry and serum PlGF and AFP at 19-24 weeks was 100%, 76% and 38% for SGA < 5(th) delivering < 32, 32-36 and ≥ 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. In a hypothetical model, it was estimated that, if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th) , it would be necessary to select 11% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 46% to be reassessed at 36 weeks; 54% would not require a third-trimester scan.

CONCLUSION

Prenatal prediction of a high proportion of SGA neonates necessitates the undertaking of screening in the third trimester of pregnancy, in addition to assessment in the second trimester, and the timing of such screening, at 32 and/or 36 weeks, should be contingent on the results of the assessment at 19-24 weeks.

Prediction of small-for-gestational-age neonates: screening by maternal biochemical markers at 30-34 weeks

OBJECTIVE

To investigate the potential value of serum placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (β-hCG) and α-fetoprotein (AFP) at 30-34 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE).

METHODS

This was a screening study in singleton pregnancies at 30-34 weeks' gestation, including 490 that delivered SGA neonates and 9360 cases that were unaffected by SGA, PE or gestational hypertension (normal outcome). Multivariable logistic regression analysis was used to determine if screening by serum PlGF, sFlt-1, PAPP-A, free β-hCG and AFP, individually or in combination, improved the prediction of SGA neonates provided by screening with maternal characteristics and medical history (maternal factors), and estimated fetal weight (EFW) from fetal head circumference, abdominal circumference and femur length.

RESULTS

Compared to the normal group, the mean log10 multiples of the median (MoM) values of PlGF and AFP were significantly lower and the mean log10 MoM values of sFlt-1 and free β-hCG were significantly higher in the SGA group with a birth weight < 5(th) percentile (SGA < 5(th)) delivering < 5 weeks following assessment. The best model for prediction of SGA was provided by a combination of maternal factors, EFW and serum PlGF. Such combined screening, predicted, at a 10% false-positive rate, 85%, 93% and 92% of SGA neonates delivering < 5 weeks following assessment with birth weight < 10(th), < 5(th) and < 3(rd) percentiles, respectively; the respective detection rates of combined screening for SGA neonates delivering ≥ 5 weeks following assessment were 57%, 64% and 71%.

CONCLUSION

Combined screening by maternal factors, EFW and serum PlGF at 30-34 weeks' gestation can identify a high proportion of pregnancies that subsequently deliver SGA neonates.

Prediction of small-for-gestational-age neonates: screening by fetal biometry at 19-24 weeks

OBJECTIVE

To investigate the value of fetal biometry at 19-24 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE), and examine the potential value of such assessment in deciding whether the third-trimester scan should be at 32 and/or 36 weeks' gestation.

METHODS

This was a screening study in 88,187 singleton pregnancies, including 5003 (5.7%) that delivered SGA neonates with birth weight < 5(th) percentile (SGA < 5(th)). Multivariable logistic regression analysis was used to determine if screening by a combination of maternal characteristics and medical history and Z-scores of fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) had significant contribution in predicting SGA neonates. A model was developed for selecting the gestational age for third-trimester assessment, at 32 and/or 36 weeks, based on the results of screening at 19-24 weeks.

RESULTS

Combined screening by maternal factors and fetal biometry at 19-24 weeks, predicted 76%, 58% and 44% of SGA < 5(th) delivering < 32, 32-36 and ≥ 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. The detection rate (DR) of SGA < 5(th) delivering at 32-36 weeks improved from 58% to 82% with screening at 32 weeks rather than at 19-24 weeks. Similarly, the DR of SGA < 5(th) delivering ≥ 37 weeks improved from 44% with screening at 19-24 weeks to 61% and 76% with screening at 32 and 36 weeks, respectively. In a hypothetical model, it was estimated that if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th), it would be necessary to select 28% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 41% to be reassessed at 36 weeks; in 59% of pregnancies there would be no need for a third-trimester scan.

CONCLUSION

Prenatal prediction of a high proportion of SGA neonates necessitates the undertaking of screening in the third trimester of pregnancy, in addition to assessment in the second trimester, and the timing of such screening, either at 32 and/or 36 weeks, should be contingent on the results of the assessment at 19-24 weeks.

Prediction of small-for-gestational-age neonates: screening by placental growth factor and soluble fms-like tyrosine kinase-1 at 35-37 weeks

OBJECTIVE

To investigate the potential value of maternal serum placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) at 35-37 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE).

METHODS

This was a screening study in singleton pregnancies at 35-37 weeks, including 158 that delivered SGA neonates with birth weight < 5(th) percentile and 3701 cases unaffected by SGA, PE or gestational hypertension. Multivariable logistic regression analysis was used to determine if measuring serum levels of PlGF and sFlt-1 improved the prediction of delivery of SGA neonates provided by screening with maternal characteristics and medical history (maternal factors), and estimated fetal weight (EFW) from fetal head circumference, abdominal circumference and femur length.

RESULTS

Compared to the normal group, the median PlGF multiples of the median (MoM) was significantly lower and the median sFlt-1 MoM was significantly higher in the SGA group. Combined screening by maternal factors and EFW at 35-37 weeks predicted, at 10% false-positive rate (FPR), 90%, 92% and 94% of SGA neonates with birth weight < 10(th), < 5(th) and < 3(rd) percentiles, respectively, delivering < 2 weeks following assessment; the respective values for SGA delivering ≥ 37 weeks were 66%, 73% and 80%. When PlGF and sFlt-1 were added to a model that combines maternal factors and EFW, sFlt-1 did not remain as a significant independent predictor of SGA < 5(th). Combined screening by maternal factors, EFW and serum PlGF, predicted, at a 10% FPR, 88%, 96% and 94% of SGA neonates with birth weight < 10(th), < 5(th) and < 3(rd) percentiles, respectively, delivering < 2 weeks following assessment and the respective values for SGA delivering ≥ 37 weeks were 64%, 75% and 80%.

CONCLUSION

sFlt-1 does not provide significant independent prediction of SGA, in the absence of PE, in addition to combined testing by maternal factors and fetal biometry at 35-37 weeks; whilst the addition of PlGF alone marginally improves the performance of screening.

Umbilical and fetal middle cerebral artery Doppler at 35-37 weeks' gestation in the prediction of adverse perinatal outcome

OBJECTIVE

To investigate the potential value of cerebroplacental ratio (CPR) at 36 weeks' gestation in the prediction of adverse perinatal outcome.

METHODS

This was a screening study in 6178 singleton pregnancies at 35-37 weeks' gestation. Umbilical artery (UA) and fetal middle cerebral artery (MCA) pulsatility index (PI) were measured and the values were converted to multiples of the median (MoM) after adjustment from variables in maternal characteristics and medical history that affect the measurements. CPR was calculated by dividing MCA-PI MoM by UA-PI MoM. Multivariable logistic regression analysis was used to determine if measuring CPR improved the prediction of adverse perinatal outcome provided by maternal characteristics, medical history and obstetric factors. The detection rate (DR) and false-positive rate (FPR) of screening by CPR were estimated for stillbirth, Cesarean section for fetal distress, umbilical arterial cord blood pH ≤ 7.0, umbilical venous cord blood pH ≤ 7.1, 5-min Apgar score < 7 and admission to the neonatal unit (NNU) and neonatal intensive care unit (NICU).

RESULTS

There was a linear association between CPR and both birth-weight Z-score and arterial or venous umbilical cord blood pH, but the steepness of the regression lines was inversely related to the interval from assessment to delivery. The performance of low CPR < 5(th) percentile in screening for each adverse outcome was poor, with DRs of 6-15% and a FPR of about 6%. In the small subgroup of the population delivering within 2 weeks of assessment, the DRs improved to 14-50%, but with a simultaneous increase in FPR, to about 10%.

CONCLUSION

The performance of CPR in routine screening for adverse perinatal outcome at 36 weeks' gestation is poor.