Reference ranges for uterine artery mean pulsatility index at 11-41 weeks of gestation

Differences in cortical development assessed by fetal MRI in late-onset intrauterine growth restriction

OBJECTIVE

The objective of the study was to evaluate cortical development parameters by magnetic resonance imaging (MRI) in late-onset intrauterine growth-restricted (IUGR) fetuses and normally grown fetuses.

STUDY DESIGN

A total of 52 IUGR and 50 control fetuses were imaged using a 3T MRI scanner at 37 weeks of gestational age. T2 half-Fourier acquisition single-shot turbo spin-echo anatomical acquisitions were obtained in 3 planes. Cortical sulcation (fissures depth corrected by biparietal diameter), brain volumetry, and asymmetry indices were assessed by means of manual delineation and compared between cases and controls.

RESULTS

Late-onset IUGR fetuses had significantly deeper measurements in the left insula (late-onset IUGR: 0.293 vs control: 0.267; P = .02) and right insula (0.379 vs 0.318; P < .01) and the left cingulate fissure (0.096 vs 0.087; P = .03) and significantly lower intracranial (441.25 cm(3) vs 515.82 cm(3); P < .01), brain (276.47 cm(3) vs 312.07 cm(3); P < .01), and left opercular volumes (2.52 cm(3) vs 3.02 cm(3); P < .01). IUGR fetuses showed significantly higher right insular asymmetry indices.

CONCLUSION

Late-onset IUGR fetuses had a different pattern of cortical development assessed by MRI, supporting the existence of in utero brain reorganization. Cortical development could be useful to define fetal brain imaging-phenotypes characteristic of IUGR.

Value of annular M-mode displacement vs tissue Doppler velocities to assess cardiac function in intrauterine growth restriction

OBJECTIVE

To compare the ability of two different methods for longitudinal annular motion measurement, M-mode and tissue Doppler imaging (TDI), to demonstrate cardiac dysfunction in intrauterine-growth-restricted (IUGR) fetuses.

METHODS

Cardiac longitudinal annular motion in the basal free wall of the left ventricle (mitral annulus), interventricular septum and tricuspid annulus was assessed in 23 early-onset IUGR cases and 43 controls by TDI (annular peak velocities) and M-mode (displacement).

RESULTS

All annular parameters were significantly decreased in the IUGR group with respect to controls using both methods. M-mode showed a trend towards equal performance as classifier between cases and controls, as compared to TDI, mainly in the tricuspid annulus.

CONCLUSIONS

Both M-mode and TDI demonstrate annular motion changes and consequently cardiac dysfunction in IUGR fetuses. M-mode imaging is simpler to perform and could be as sensitive as TDI for detecting subtle changes.

Uterine artery Doppler and sFlt-1/PlGF ratio: usefulness in diagnosis of pre-eclampsia

OBJECTIVE

To evaluate the usefulness of the mean pulsatility index of the uterine arteries (mPI-UtA) and automated measurement of the soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio on suspicion or at diagnosis of pre-eclampsia (PE).

METHODS

Patients with singleton pregnancies with PE (n = 60) diagnosed according to current recommendations, or with suspected PE (n = 32) defined by (1) blood pressure (BP) ≥ 160/100 mmHg, (2) BP ≥ 140/90 mmHg or proteinuria, together with suggestive clinical symptoms or (3) intrauterine growth restriction (IUGR) at < 34 + 0 weeks, were enrolled and mPI-UtA and the sFlt-1/PlGF ratio were measured. Values > 95(th) centile were considered abnormal. All cases were classified according to occurrence of PE and/or IUGR and subclassified, depending on gestational age at delivery, as early (< 34 + 0 weeks) or late (≥ 34 + 0 weeks).

RESULTS

PE was confirmed in 72 cases, in which 32 early deliveries occurred. Isolated IUGR was diagnosed in nine early cases and one late case, while the remaining 10 cases were late deliveries without PE or IUGR. In pregnancies in which PE and IUGR were excluded, mPI-UtA was abnormal in 40% but the sFlt-1/PlGF ratio was normal in 100%. In early PE, mPI-UtA at diagnosis was abnormal in 100% of cases with IUGR and in 91% without IUGR, while sFlt-1/PlGF was abnormal in 100% and 96%, respectively. In late PE, mPI-UtA was abnormal in 50% and 37% of cases with and without IUGR while the sFlt-1/PlGF ratio was abnormal in 50% and 26%, respectively.

CONCLUSION

Abnormal mPI-UtA and sFlt-1/PlGF ratio are common in early PE. In late PE, mPI-UtA is normal in most cases and thus not diagnostically useful. The sFlt-1/PlGF ratio shows high specificity but low sensitivity to confirm PE when suspected.

Association between first trimester vaginal bleeding and uterine artery Doppler measured at second and third trimesters of pregnancy

OBJECTIVE

To evaluate the prevalence of first trimester vaginal bleeding among patients with abnormal second and third trimester uterine artery Doppler.

METHODS

A prospective study of patients with a uterine artery Doppler measurement between 27 and 42 weeks' gestation was undertaken. A comparison was made between two groups: patients with and without first trimester vaginal bleeding. Abnormal uterine artery Doppler was defined as PI >95th% or the presence of a diastolic notch.

RESULTS

Of the 277 patients that were included in the study, 65 (23%) had first trimester vaginal bleeding. No differences were noted in uterine artery Doppler waveforms among patients with and without first trimester vaginal bleeding. Among patients with first trimester vaginal bleeding, 9 (14%) had a bilateral uterine artery notch and 56 (86%) did not, compared with 51 (24%) and 161 (76%), in the control group, respectively. Patients with first trimester vaginal bleeding, and a bilateral uterine artery notch had significantly higher rates of small for gestational age neonates, low-Apgar scores (<7) at one minute and cesarean deliveries compared to patients with first trimester vaginal bleeding who did not have bilateral uterine artery notch.

CONCLUSION

First trimester vaginal bleeding was not associated with a higher incidence of abnormal uterine artery waveforms or with placental related conditions. However, adverse perinatal outcomes were found when first trimester vaginal bleeding was associated with second and third trimester bilateral uterine artery notchs.

Second- and third-trimester placental hemodynamics and the risks of pregnancy complications: the Generation R Study

Characteristics of the uterine and umbilical artery blood flow patterns are indirect measures of uteroplacental circulation. We examined whether uterine and umbilical artery resistance indices are influenced by maternal demographic and lifestyle characteristics, track from the second trimester to the third, and are associated with the risk of pregnancy complications. This analysis was embedded among 7,660 pregnant women in the Generation R Study (Rotterdam, the Netherlands, 2001-2005). Placental resistance indices were assessed in the second and third trimesters. Information about pregnancy outcomes was obtained from medical records. Maternal characteristics affected second- and third-trimester placental resistance indices. Correlation coefficients for correlation between the second and third trimesters were 0.50 and 0.32 for uterine artery resistance index and umbilical artery pulsatility index, respectively. Higher placental resistance indices in the second and third trimesters and persistence in the highest tertile of uterine artery resistance index from the second trimester to the third were associated with the risks of preeclampsia, preterm birth, and small size for gestational age at birth (all P's < 0.05). Our study shows that placental resistance indices are influenced by maternal demographic and lifestyle characteristics and track moderately from the second trimester to the third. Increased placental resistance indices in the second and third trimesters are associated with increased risks of adverse pregnancy outcomes.

Uterine blood flow in a psychiatric population: impact of maternal depression, anxiety, and psychotropic medication

BACKGROUND

Accumulating evidence suggests that fetal exposure to maternal psychiatric symptoms is associated with future risk for psychopathology. One potential pathway is distress-linked constriction in uterine or umbilical blood flow (UBF). With approximately 6.6% of pregnant women taking an antidepressant, an ecologically valid investigation of this hypothesis must consider the potential concomitant influence of pharmacotherapy on UBF.

METHODS

Pregnant women (n = 101) with lifetime histories of mental illness were evaluated every 4 to 6 weeks during gestation for mood symptoms and medication use; women underwent an ultrasound examination for UBF at approximately 25 weeks gestation.

RESULTS

No associations were observed between UBF and three assessments of maternal prenatal depression and anxiety (acute: coincident with the UBF scan; proximal: within 2 weeks of the scan; chronic: serial symptom ratings). Chronic and acute use of bupropion was associated with reduced UBF, even after controlling for pregnancy complications. Chronic use of atypical antipsychotics also was associated with decreased UBF. There were no associations between serotonergic antidepressant use and UBF.

CONCLUSIONS

Contrary to a popular hypothesis, depression and anxiety-associated reductions in UBF may not be a pathway by which risk is conferred during prenatal development. However, while requiring replication, our findings suggest that prenatal bupropion exposure may be associated with reductions in UBF.

Prediction of pre-eclampsia by a combination of maternal history, uterine artery Doppler, and mean arterial pressure (a prospective study of 200 cases)

OBJECTIVE

To determine the clinical value of uterine artery Doppler Pulsatility index (PI) at 22-24 + 6 weeks scan and importance of maternal history and mean arterial pressure (MAP) in the prediction of pre-eclampsia.

MATERIALS AND METHODS

This was a prospective screening study of 200 women with singleton pregnancy. Maternal history and blood pressure were recorded, and MAP was calculated. Transabdominal Doppler ultrasound of uterine artery was performed. Mean PI was calculated, and the presence or the absence of bilateral early diastolic notch was noted. Women were then followed up through pregnancy and delivery for the development of pre-eclampsia, gestational hypertension, and SGA.

RESULTS

The mean ± SD PI value for subjects who had an adverse pregnancy outcome was significantly higher (0.84 ± 0.28) than mean ± SD PI value for subjects who had normal pregnancy outcome (0.71 ± 0.16) with P value <0.000.

CONCLUSION

Second trimester uterine artery Doppler is a useful screening method for identification of high risk pregnancy in women who can be kept under close surveillance for better maternal and neonatal outcome. This test works better when combined with previous history of pre-eclampsia and MAP.

Comparative Study of Endothelial Function and Uterine Artery Doppler Velocimetry between Pregnant Women with or without Preeclampsia Development

Background. Poor placentation and systemic endothelial dysfunction have been identified as main events in Preeclampsia (PE). The relationship and chronology of these phenomena are important if we are to understand the pathophysiological mechanisms underlying this major clinical problem. Objectives. To compare the evolution of placentation and endothelial function in normotensive and preeclamptic pregnancies. Patients and methods. In a prospective cohort study, 59 pregnant women with a high risk of developing PE were subjected to flow-mediated dilation (FMD) and to Doppler velocimetry of uterine arteries in order to obtain their Pulsatility Index (UtA-PI). The variations in the FMD and UtA-PI values, between 16⁺⁰ and 19⁺⁶ and 24⁺⁰ and 27⁺⁶ weeks of gestation, were compared, taking PE development into consideration. Results. Nine patients developed PE and the other 50 women remained normotensive. At 16⁺⁰ to 19⁺⁶ weeks of pregnancy, patients that developed PE presented higher values of UtA-PI than the normotensive group, but there was no difference in FMD results between them. At 24⁺⁰ to 27⁺⁶ weeks, the patients that developed PE presented higher values of UtA-PI and lower values of FMD than the women that remained normotensive. Conclusions. These results corroborate the evidence that endothelial injury is secondary to poor placentation.

Comparison of uterine artery Doppler in pregnant women with thrombophilia treated by LMWHs and without thrombophilia

OBJECTIVE

The aim of this study was to use uterine artery Doppler ultrasonography to investigate the cases of women with thrombophilia who used LMWH during the 18-22-week period of gestation.

METHODS

This retrospective study was conducted at our university between January 2005 and July 2010. 64 patients were treated with low-dose LMWHs (enoxaparine 40 mg) from the beginning of pregnancy until 36 weeks of gestation. Fifty control subjects were also included in this study. Transabdominal ultrasound examination and bilateral uterine artery Doppler measurements pulsatility index (PI), resistive index (RI), and systole/diastole measurement (S/D) were performed during the 18-22-weeks period of gestation.

RESULTS

No significant differences were found between the groups with respect to maternal age or gestational age at the time of uterine artery Doppler. However, the mean PI (1.07 ± 0.46 for LMWH group and 0.91 ± 0.31 for control, p = 0.036) and the mean RI (0.59 ± 0.12 for LMWH group and 0.54 ± 0.10 for control, p = 0.021) were significantly higher in the trombophilia group.

CONCLUSION

Women with trombophilia still have an increased mean PI and RI, as determined by uterine artery Doppler ultrasonography during the 18-22-week period of gestation, even if they use LMWH.

Estimated weight centile as a predictor of perinatal outcome in small-for-gestational-age pregnancies with normal fetal and maternal Doppler indices

OBJECTIVE

To evaluate the risk of adverse perinatal outcome according to estimated fetal weight (EFW) in a cohort of term small-for-gestational-age (SGA) pregnancies with normal umbilical, fetal middle cerebral and maternal uterine artery Doppler indices.

METHODS

A cohort of 132 term SGA fetuses with normal umbilical artery pulsatility index (PI), mean uterine artery PI and cerebroplacental ratio was compared to a control group of 132 appropriate-for-gestational-age babies, matched by gestational age at delivery. The capacity of the EFW percentile to predict Cesarean delivery, Cesarean delivery for non-reassuring fetal status (NRFS), neonatal acidosis and days of neonatal hospitalization was analyzed.

RESULTS

As a whole, SGA fetuses with normal Doppler findings did not show a statistically significant difference for intrapartum Cesarean delivery (22.0 vs. 15.9%; P = 0.21) and neonatal acidosis (3.3 vs. 1.5%; P = 0.30), but had significantly higher risk for Cesarean delivery for NRFS (15.9 vs. 5.3%; P < 0.01) and longer neonatal hospitalization (1.39 vs. 0.87 days; P < 0.05) than did controls. SGA fetuses with EFW < 3(rd) centile had a significantly higher incidence of intrapartum Cesarean delivery (30.0 vs. 15.3%; P = 0.04), Cesarean delivery for NRFS (25.0 vs. 8.3%; P < 0.01) and longer neonatal hospitalization (2.0 vs. 0.9 days; P < 0.01) than those with EFW ≥ 3(rd) centile. SGA cases with EFW ≥ 3(rd) centile had perinatal outcomes similar to those of controls with normal EFW.

CONCLUSION

Among SGA fetuses with normal placental and cerebral Doppler ultrasound findings, EFW < 3(rd) centile discriminates between those with a higher risk for adverse perinatal outcome and those with outcomes similar to those of normally grown fetuses.

Increased uterine artery pulsatility index at 34 weeks and outcome of pregnancy

OBJECTIVES

To evaluate pregnancy outcome in patients with increased uterine artery (UtA) pulsatility at 34 weeks' gestation as an isolated finding.

METHODS

Normotensive women attending at 34 weeks' gestation for fetal growth assessment were enrolled in the study if fetal growth was appropriate for age and mean UtA pulsatility index (PI) was persistently above the 95(th) centile for gestational age. Patients were excluded with any of the following conditions: multiple pregnancy, sonographic suspicion of fetal anomaly or fetal growth restriction, history of chronic maternal disease, hypertensive disorder or diabetes in the current pregnancy or one or more adverse events in their past obstetric history. The control group consisted of age- and body mass index-matched low-risk women attending at 34 weeks with normal uterine artery Doppler since the midtrimester.

RESULTS

Sixty-six normotensive patients with normal fetal growth and increased UtA-PI at 34 weeks were included in the study group. Women with abnormal Doppler findings compared with controls showed significantly lower gestational age at delivery (38.2 ± 1.6 vs. 38.9 ± 1.3 weeks, P = 0.006), birth weight (2942 ± 583 vs. 3404 ± 469 g, P < 0.001), birth-weight Z-score (-0.61 ± 1.07 vs. 0.19 ± 1.05, P < 0.001) and increased risk of a small-for-gestational-age (SGA) newborn (13/66 vs. 1/66, P < 0.001). The occurrence of late pre-eclampsia (3/66 vs. 0/66, P = 0.24), admission to the neonatal intensive care unit (6/66 vs. 4/66, P = 0.74), rate of induction of labor (16/66 vs. 14/66, P = 0.83) and rate of Cesarean section due to fetal distress (6/66 vs. 3/66, P = 0.49) were comparable between the two groups.

CONCLUSION

Increased UtA-PI as an isolated finding at 34 weeks' gestation is associated with an increased risk of delivering an SGA neonate.

Reference ranges for Doppler assessment of uterine artery resistance and pulsatility indices in dichorionic twin pregnancies

OBJECTIVES

To construct reference ranges of uterine artery Doppler parameters against gestation in twin pregnancies and to present charts of the pulsatility index (PI) and resistance index (RI) for clinical use.

METHODS

This was an observational study of the uterine circulation in 557 women with dichorionic twin pregnancies at 17-38 weeks' gestation. Uterine artery measurements were performed by color and pulsed Doppler imaging. The uterine artery PI and RI were calculated as a mean of both sides. Reference ranges were constructed by regression of each index on gestational age. For this purpose, a regression model with fractional polynomials was fitted to the data. Furthermore, the presence of uterine artery notching was recorded.

RESULTS

New reference curves and tables of percentiles of the uterine artery PI and RI are presented. The calculated indices both showed a significant decrease with gestational age. Compared with singleton values, mean twin PI values were lower during the whole course of pregnancy. The prevalence of bilateral notching was 4.6% at 17-19 weeks' gestation and 3.1% at 20-24 weeks.

CONCLUSIONS

Uterine artery Doppler indices in twin pregnancies are lower than in singleton pregnancies. Therefore, the use of uterine artery reference ranges adapted to twin gestations seems more appropriate for identifying low- and high-risk groups.

Screening for pre-eclampsia--lessons from aneuploidy screening

BACKGROUND

Antenatal screening for aneuploidy is an established routine clinical practice worldwide. The same statistical methodology, developed and refined over three decades, might be adapted to screening for pre-eclampsia.

METHODS

The published literature is reviewed for evidence that the methodology is valid for pre-eclampsia using first trimester maternal serum PP13, PAPP-A, PlGF, ADAM12 and inhibin A, together with MAP and uterine artery Doppler PI. Risk is estimated for both early onset pre-eclampsia, requiring delivery before 34 weeks, or late onset disease. Prior risk from the background prevalence multiplied by likelihood ratios (LRs) for ethnicity, parity, adiposity and family history is multiplied by an LR from the screening marker profile. Markers are expressed in multiples of the gestation-specific median and adjusted for body mass, ethnicity and smoking status as appropriate. A standardized population with a fixed distribution of risk factors and a multi-variate Gaussian model of marker profiles is used to predict performance.

RESULTS

There is sufficient published data to estimate individual risks reasonably well. Modeling predicts that using PAPP-A and one other serum marker, together with the physical markers more than two-thirds of early and one-third of late onset cases can be detected by classifying less than 2% of pregnancies as high risk; three-quarters of early case could be detected with a 5% high risk rate.

CONCLUSION

Whilst more data on some markers is still required modeling so far suggests that extending first trimester aneuploidy screening programs to include pre-eclampsia screening would yield a high detection. However, prospective studies are needed to verify the model predictions.

A new non-invasive method for measuring uterine vascular resistance and its relationship to uterine artery Doppler indices: a longitudinal study

OBJECTIVES

To describe a new method for measuring uterine vascular resistance (R(uta) ), establish longitudinal reference ranges and explore the relationship between uterine artery (UtA) Doppler indices and R(uta) .

METHODS

This was a longitudinal study of 53 low-risk pregnancies. Doppler ultrasonography was used to measure UtA velocities, and the pulsatility index (PI), resistance index (RI) and systolic/diastolic velocity (S/D) ratio were calculated. R(uta) was calculated as a ratio between maternal mean arterial pressure and UtA time-averaged maximum velocity.

RESULTS

At 22 + 0 to 39 + 6 weeks of gestation, the mean R(uta) decreased from 1628 to 1180 dyne.s/cm(3) (P < 0.0001). UtA velocities increased (P < 0.0001), whereas the PI (0.79-0.56), RI (0.51-0.40) and S/D ratio (2.0-1.7) decreased (P < 0.0001). R(uta) and the UtA Doppler indices were positively associated (P = 0.003-0.001).

CONCLUSION

We describe a non-invasive method for measuring R(uta) and provide reference ranges for serial evaluation of UtA velocities, Doppler indices and R(uta) .

The impact of umbilical and uterine artery Doppler indices on antenatal course, labor and delivery in a low-risk primigravid population

AIMS

To evaluate the impact of umbilical and uterine artery Doppler in the second and third trimester on antenatal course, labor and delivery in a low-risk primigravid population.

METHODS

Prospective recruitment of 1011 low-risk primigravidas with uterine and umbilical artery Doppler assessment at 22-24 weeks and 36 weeks. All mothers and infants were reviewed postnatally with a retrospective analysis of ultrasound and clinical outcome data.

RESULTS

Elevated uterine artery indices were associated with increased rates of threatened miscarriage, higher rates of pre-eclampsia (PET) and a higher incidence of fetal birth weight <2nd and 9th centile for gestation. Uterine artery pulsatility index (PI) >95th centile for gestation was associated with statistically higher rates of small-for-gestational age (SGA) infants. Elevated umbilical artery indices were associated with higher rates of induction of labor and a higher incidence of fetal birth weight infants <2nd and 9th centile for gestation. Umbilical artery PI >95th centile for gestation was associated with statistically higher rates of SGA infants.

CONCLUSION

Elevated uterine and umbilical artery indices are associated with higher rates of maternal and fetal disease.

Longitudinal changes in uterine, umbilical and fetal cerebral Doppler indices in late-onset small-for-gestational age fetuses

OBJECTIVES

To determine the longitudinal trends and rates of conversion of normal to abnormal uterine (UtA), umbilical (UA) and middle cerebral artery (MCA) Doppler velocimetry throughout the third trimester in late-onset small-for-gestational-age (SGA) fetuses.

METHODS

UtA, UA and MCA Doppler velocimetry was serially performed in a cohort of singleton consecutive late-onset SGA fetuses with normal Doppler values at diagnosis. The rate of conversion of normal to abnormal Doppler values was evaluated by survival analysis. Longitudinal trends were modeled by means of multilevel analysis.

RESULTS

A total of 616 scans were performed on 171 SGA fetuses. Mean gestational age at inclusion and at delivery was 34.1 (SD 1.6) and 38.7 (SD 1.7) weeks, respectively. The proportions of abnormal UtA (2.3 vs. 4.1%) and UA (2.3 vs. 2.9%) pulsatility index (PI) were not significantly different between 37 weeks and before delivery. On the other hand, the proportions of abnormal MCA-PI (4.1 vs. 13.5%) and cerebroplacental ratio (CPR) (7 vs. 22.8%) were significantly different between these two examinations. The remaining proportion of cases with normal UtA-, UA- and MCA-PIs and CPR at 40 weeks were 98.6, 94.5, 85 and 49.6%, respectively. Whereas a slight increasing trend was observed for the UtA-PI (β = 0.002) and UA-PI (β = 0.01), MCA-PI (β = 0.044) and CPR (β = 0.124) showed a progressive decrease until delivery.

CONCLUSIONS

Late-onset SGA fetuses with normal Doppler velocimetry upon diagnosis show progression from 37 weeks' gestation with worsening CPR followed by a decrease in MCA-PI.

Associations between cardiovascular parameters and uteroplacental Doppler (blood) flow patterns during pregnancy in women with congenital heart disease: Rationale and design of the Zwangerschap bij Aangeboren Hartafwijking (ZAHARA) II study

BACKGROUND

Previous research has shown that women with congenital heart disease (CHD) are more susceptible to cardiovascular, obstetric, and offspring events. The causative pathophysiologic mechanisms are incompletely understood. Inadequate uteroplacental circulation is an important denominator in adverse obstetric events and offspring outcome. The relation between cardiac function and uteroplacental perfusion has not been investigated in women with CHD. Moreover, the effects of physiologic changes on pregnancy-related events are unknown. In addition, long-term effects of pregnancy on cardiac function and exercise capacity are scarce.

METHODS

Zwangerschap bij Aangeboren Hartafwijking (ZAHARA) II, a prospective multicenter cohort study, investigates changes in and relations between cardiovascular parameters and uteroplacental Doppler flow patterns during pregnancy in women with CHD compared to matched healthy controls. The relation between cardiovascular parameters and uteroplacental Doppler flow patterns and the occurrence of cardiac, obstetric, and offspring events will be investigated. At 20 and 32 weeks of gestation, clinical, neurohumoral, and echocardiographic evaluation and fetal growth together with Doppler flow measurements in fetal and maternal circulation are performed. Maternal evaluation is repeated 1 year postpartum.

IMPLICATIONS

By identifying the factors responsible for pregnancy-related events in women with CHD, risk stratification can be refined, which may lead to better pre-pregnancy counseling and eventually improve treatment of these women.

Gestational age- and estimated fetal weight-adjusted reference ranges for myocardial tissue Doppler indices at 24-41 weeks' gestation

OBJECTIVES

To construct gestational age (GA)- and estimated fetal weight (EFW)-adjusted reference ranges for tissue Doppler cardiac function parameters from 24 to 41 weeks' gestation.

METHODS

This was a prospective cross-sectional observational study involving 213 singleton pregnancies between 24 and 41 weeks' gestation. Myocardial peak velocities and myocardial performance index (MPI') were measured by tissue Doppler ultrasonography (values indicated by 'prime') in the left and right annulus and interventricular septum. Left and right atrioventricular parameters were also measured by conventional Doppler and ratios between the values found by the two methods calculated. Regression analysis was used to determine GA- and EFW-adjusted reference ranges and to construct nomograms for tissue Doppler parameters.

RESULTS

All myocardial peak velocities, left and right E'/A' and left MPI' showed a progressive increase with GA. In contrast, left and right E/E' showed a progressive decline. Septal E'/A', and right and septal MPI' remained constant. Myocardial peak velocities showed a progressive increase with increasing fetal weight.

CONCLUSIONS

Normal data of fetal myocardial peak velocities, their ratios and MPI' by tissue Doppler adjusted by GA and EFW are provided. The reported reference values may be useful in research or clinical studies and can be used in fetuses with intrauterine growth restriction.

Ultrasound predictors of birth weight in euploid fetuses with isolated single umbilical artery

OBJECTIVE

To evaluate ultrasound parameters, including Doppler assessment, that may influence fetal growth and birth weight in cases of isolated single umbilical artery (SUA).

METHODS

Sixty pregnant women with isolated SUA were studied. Doppler measurements of umbilical artery (UA), mean uterine artery (UtA) and fetal middle cerebral artery (MCA) pulsatility indices (PI) were recorded and the corresponding Z-scores were calculated according to gestational age at time of measurement. Additionally, the umbilical vein (UV) to UA diameter and perimeter ratios were calculated. The relationships between ultrasound parameters and customized birth-weight centiles according to sex and gestational age were analyzed.

RESULTS

There were significant correlations between birth-weight centile and the Z-score of mean UtA-PI (r = - 0.417, P = 0.008) and the UV to UA perimeter ratio (r = 0.567, P = 0.001). A significant positive correlation between Z-scores of UA-PI and mean UtA-PI (r = 0.428, P = 0.007) was also found. When using stepwise linear regression analysis both mean UtA-PI Z-scores and UV to UA perimeter ratio were included in the predictive model of birth-weight centile (R(2) = 0.46, P < 0.001).

CONCLUSIONS

Doppler assessment of mean UtA-PI and the UV to UA perimeter ratio may be useful in the clinical management of isolated SUA cases by identifying a subgroup at higher risk for fetal growth restriction.

Persistence of increased uterine artery resistance in the third trimester and pregnancy outcome

OBJECTIVE

To evaluate whether the persistence of abnormal findings in the third trimester following increased uterine artery (UtA) resistance in the second trimester is related to adverse pregnancy outcome.

METHODS

Low-risk nulliparous women with increased UtA mean pulsatility index (PI) at 20-22 weeks underwent repeat Doppler interrogation at 26-28 weeks and were divided into two groups: those with persistently abnormal Doppler and those with normalized UtA findings. Pregnancy outcome was noted for all patients and compared with that of 104 controls.

RESULTS

We examined 104 women with increased UtA resistance in the second trimester and in 62 (59.6%) cases the abnormal uteroplacental Doppler findings persisted to 26-28 weeks. Compared with controls and with patients with normalized Doppler at the third-trimester scan, patients with persistently abnormal Doppler results had a significantly higher risk of pre-eclampsia (10/62 vs. 1/104, P = 0.002 and 10/62 vs. 1/42, P = 0.047, respectively), small-for-gestational age (SGA) fetus (20/62 vs. 1/104, P < 0.001 and 20/62 vs. 4/42; P = 0.007, respectively) and admission of the infant to a neonatal intensive care unit (16/62 vs. 4/104; P < 0.001 and 16/62 vs. 1/42; P < 0.001, respectively). Compared with controls, cases with normalization had an increased risk of SGA (4/42 vs. 1/104, P = 0.03), but there were no significant differences for the other outcome measures.

CONCLUSIONS

In low-risk nulliparous women with increased UtA resistance in the second trimester, the persistence of abnormal Doppler findings at 26-28 weeks is associated with an increased risk of obstetric complications when compared with both controls and patients with third-trimester Doppler normalization.

The prognostic role of uterine artery Doppler investigation in patients with severe early-onset preeclampsia

OBJECTIVE

The purpose of this study was to evaluate the prediction capacity of uterine artery Doppler investigation for maternal and neonatal complications in women who are admitted with severe early-onset preeclampsia.

STUDY DESIGN

A uterine artery Doppler examination was performed at admission for patients with severe early-onset (<34 weeks of gestation) preeclampsia. The maternal and neonatal outcome of women with abnormal uterine Doppler results was compared with those with normal Doppler results.

RESULTS

One hundred twenty patients were included. In 53% of them, uterine Doppler results were abnormal. This group had a lower gestational age at delivery (30.2 vs 32.7 weeks; P < .001) and a higher proportion of small-for-gestational age infants (87.5% vs 67.9%; P = .009). Neonatal (40.6% vs 14.3%; P = .01) and maternal (28.1% vs 5.4%; P = .001) complications were more common in the abnormal uterine Doppler group.

CONCLUSION

Women with severe early-onset preeclampsia are at higher risk of maternal and neonatal complications if abnormal uterine blood flow is present.

An imbalance between angiogenic and anti-angiogenic factors precedes fetal death in a subset of patients: results of a longitudinal study

OBJECTIVE

Women with a fetal death at the time of diagnosis have higher maternal plasma concentrations of the anti-angiogenic factor, soluble vascular endothelial growth factor receptor (sVEGFR)-1, than women with a normal pregnancy. An important question is whether these changes are the cause or consequence of fetal death. To address this issue, we conducted a longitudinal study and measured the maternal plasma concentrations of selective angiogenic and anti-angiogenic factors before the diagnosis of a fetal death. The anti-angiogenic factors studied were sVEGFR-1 and soluble endoglin (sEng), and the angiogenic factor, placental growth factor (PlGF).

METHODS

This retrospective longitudinal nested case-control study included 143 singleton pregnancies in the following groups: (1) patients with uncomplicated pregnancies who delivered a term infant with an appropriate weight for gestational age (n=124); and (2) patients who had a fetal death (n=19). Blood samples were collected at each prenatal visit, scheduled at 4-week intervals from the first trimester until delivery. Plasma concentrations of sVEGFR-1, sEng, and PlGF were determined by specific and sensitive ELISA. A linear mixed-effects model was used for analysis.

RESULTS

(1) The average profiles of analyte concentrations as a function of gestational age for sVEGFR-1, sEng and PlGF were different between women destined to have a fetal death and those with a normal pregnancy after adjusting for covariates (p<0.05); (2) Plasma sVEGFR-1 concentrations in patients destined to have a fetal death were significantly lower between 7 and 11 weeks of gestation and became significantly higher than those of women with a normal pregnancy between 20 and 37 weeks of gestation (p<0.05); (3) Similarly, plasma sEng concentrations of women destined to have a fetal death were lower at 7 weeks of gestation (p=0.04) and became higher than those of controls between 20 and 40 weeks of gestation (p<0.05); (4) In contrast, plasma PlGF concentrations were higher among patients destined to develop a fetal death between 7 and 14 weeks of gestation and became significantly lower than those in the control group between 22 and 39 weeks of gestation (p<0.05); (5) The ratio of PlGF/(sVEGFR-1 × sEng) was significantly higher in women destined to have a fetal death between 7 and 13 weeks of gestation (94-781%) and significantly lower (44-75%) than those in normal pregnant women between 20 and 40 weeks of gestation (p<0.05); (6) Similar results were obtained when patients with a fetal death were stratified into those who were diagnosed before or after 37 weeks of gestation.

CONCLUSIONS

Fetal death is characterised by higher maternal plasma concentrations of PlGF during the first trimester compared to normal pregnancy. This profile changes into an anti-angiogenic one during the second and third trimesters.