Fetal weight projection model to define growth velocity and validation against pregnancy outcome in a cohort of serially scanned pregnancies

The impact of prenatal exposure to fine particulate matter and its components on maternal and neonatal thyroid function and birth weight: a prospective cohort study

Maternal and child health has garnered considerable attention recently. The effects of prenatal exposure to PM2.5 and its components on thyroid function in both mothers and fetuses, as well as on offspring birth weight, remain unexplored. This study involved 446 mother-infant pairs from a cohort study in Ma'anshan, China, during 2021-2022. Air pollution data were obtained from the Tracking Air Pollution (TAP) project. Thyroid hormone levels (FT3, FT4, and TSH) were measured in maternal blood samples taken at various pregnancy stages and in cord blood. We employed multiple analytical methods to evaluate the effects of PM2.5 and its components on maternal thyroid function and birth weight z-score (BWz). The GLR analysis reveals that the effect of PM2.5 and its components on BWz differs according to the pregnancy stage and the specific pollutant involved. During the late pregnancy, increased exposure to PM2.5 and specific components (for instance,NO 3 _ and SO 4 2 - ) was correlated with elevated maternal FT4 levels (p < 0.05) and reduced BWz (p < 0.05). QgC results illustrated a notable negative correlation between heightened PM2.5 exposure and BWz in late pregnancy. BKMR analysis confirmed that overall exposure to PM2.5 and its components negatively impacted BWz during the third trimester. Mediation analysis showed that changes in maternal FT4 levels accounted for approximately 8.52%, 8.05%, and 8.13% of the negative effects on BWz from exposure to NH 4 + , NO 3 _ and SO 4 2 - , respectively (p < 0.05). In healthy pregnancies, exposure to PM2.5 and its components during the late pregnancy is linked to alterations in maternal thyroid hormone levels, potentially leading to reduced birth weight. Maternal FT4 levels may mediate the connection between PM2.5 components exposure and reduced the weight of offspring.

Fetuses with deceleration of growth improve their growth following maternal rest

OBJECTIVE

The purpose of this study was to determine if fetuses with deceleration of growth velocity resulting in an EFW <10th percentile increase their growth above the 10th percentile following 2 weeks of maternal rest in the left lateral recumbent position.

METHODS

This was a retrospective observational study of 265 fetuses with the prenatal diagnosis of an EFW <10th percentile. Fetuses were classified by four definitions of abnormal growth velocity: (1) a growth velocity less than 20 g/day, (2) 30 percentile decrease in the EFW, (3) 50 percentile decrease in the EFW, and (4) abnormal growth trajectory. Once the fetuses were identified with an EFW <10th percentile the patient was requested to begin 2 weeks of rest in the left lateral recumbent position during her waking hours following which the EFW was reassessed 2 week later to determine the effect of maternal rest on the EFW.

RESULTS

Irrespective of the four types of decreased growth velocity described in the methods section, there was as significant increase (p < 0.001) in the EFW following 2 weeks of maternal rest as follows: (1) growth less than 20 g/day (75%); (2) decrease of 30 or more EFW percentiles (79%); (3) decrease of 50 or more EFW percentiles (64%); and abnormal growth trajectory (77%).

CONCLUSIONS

This suggests an important role of increased maternal cardiac output as the result of resting in the left lateral recumbent position that may be associated with improved fetal growth. These observations should be the basis for future prospective randomized trials to test this hypothesis.

Fetal size vs growth: comparative analysis of 3 models of growth velocity based on third trimester estimated fetal weights for identifying stillbirth risk

BACKGROUND

Fetal growth velocity is being recognized as an important parameter by which to monitor fetal wellbeing, in addition to assessment of fetal size. However, there are different models and standards in use by which velocity is being assessed.

OBJECTIVE

We wanted to investigate 3 clinically applied methods of assessing growth velocity and their ability to identify stillbirth risk, in addition to that associated with small for gestational age.

STUDY DESIGN

Retrospective analysis of prospectively recorded routine-care data of pregnancies with 2 or more third trimester scans in New Zealand. Results of the last 2 scans were used for the analysis. The models investigated to define slow growth were (1) 50+ centile drop between measurements, (2) 30+ centile drop, and (3) estimated fetal weight below a projected optimal weight range, based on predefined, scan interval specific cut-offs to define normal growth. Each method's ability to identify stillbirth risk was assessed against that associated with small-for-gestational age at last scan.

RESULTS

The study cohort consisted of 71,576 pregnancies. The last 2 scans in each pregnancy were performed at an average of 32+1 and 35+6 weeks of gestation. The 3 models defined "slow growth" at the following differing rates: (1) 50-centile drop 0.9%, (2) 30-centile drop 5.1%, and (3) below projected optimal weight range 10.8%. Neither of the centile-based models identified at-risk cases that were not also small for gestational age at last scan. The projected weight range method identified an additional 79% of non-small-for-gestational-age cases as slow growth, and these were associated with a significantly increased stillbirth risk (relative risk, 2.0; 95% CI, 1.2-3.4).

CONCLUSION

Centile-based methods fail to reflect adequacy of fetal weight gain at the extremes of the distribution. Guidelines endorsing such models might hinder the potential benefits of antenatal assessment of fetal growth velocity. A new, measurement-interval-specific projection model of expected fetal weight gain can identify fetuses that are not small for gestational age, yet at risk of stillbirth because of slow growth. The velocity between scans can be calculated using a freely available growth rate calculator (www.perinatal.org.uk/growthrate).

Ultrasound parameters of arteries and heart in normal fetuses

BACKGROUND

Currently, no normal ultrasound data of the fetuses during the 20-40 gestation have been obtained for references of fetal growth and development. If such ultrasound data existed for prenatal diagnosis of possible diseases and abnormalities, neonates would be able to get timely treatment immediately after birth. This study was thus performed to obtain ultrasound parameters of normal fetuses during the 20-40 week gestation and the distribution of ultrasound parameters with the gestational age for references of detecting potential fetal diseases and abnormalities.

METHODS

Normal fetuses without any abnormalities were enrolled, and the ultrasound parameters of the general biology, arteries, and aorta were measured and analyzed.

RESULTS

417 normal fetuses were enrolled. A significant (P < 0.05) negative correlation with the gestational age was detected in the peak systolic velocity/peak diastolic velocity (S/D), pulsatility index (PI) and resistance index (RI) of the umbilical artery (UA). A relatively stable relationship with the gestational age was detected in the fetal weight%, S/D, PI and RI of the middle cerebral artery (MCA), peak systolic velocity (PSV) and velocity time integral (VTI) of the intra-abdominal UA, fetal heart to chest ratio, mitral valve (MV)- and tricuspid valve (TV)-E/A peak flow velocity, aortic isthmic Z-score and displacement, distance between the brachiocephalic artery-left common carotid artery (BA-LCCA) and LCCA-left subclavian artery (LSA), Z-score of aorta, ascending aorta (AAO), pulmonary artery (PA), main pulmonary artery (MPA), and descending aorta (DAO). A significant (P < 0.05) positive correlation with the gestational age was detected in the fetal biological data, MCA PSV and VTI, free-UA PSV and VTI and cardio-thoracic ratio, cardiac parameters, ductus arteriosus (DA) and isthmus diameter, aortic parameters, PA and MPA diameter, MPA PSV and VTI, isthmus flow volume and velocity and PA flow volume, DA and BA parameters, and LCCA and LSA parameters (flow volume, PSV, and VTI).

CONCLUSION

A certain correlation and distribution trend is detected in the ultrasound parameters of normal fetuses, and the ratios among different parameters remain relative stable. These findings can be used for determination of abnormal growth of the fetuses in prenatal ultrasound scan.

Fetal Growth Velocity-A Breakthrough in Intrauterine Growth Assessment?

The pursuit of assessing fetal well-being in obstetrical practice remains a central tenet, propelling ongoing endeavors to explore innovative markers and diagnostic methodologies aimed at prognosing potential perinatal adversities. Deviations from standard patterns of intrauterine growth, whether exhibiting excessive or insufficient trajectories, stand as pivotal indices hinting at underlying pathophysiological processes or heightened concurrent medical conditions. Initiatives like the Delphi consensus and the INTERGROWTH-21st project strive to refine diagnostic criteria and establish international standards for fetal growth assessment. This article aims to present the current knowledge regarding the assessment of abnormal growth, including novel methods such as growth velocity. Integrating fetal growth velocity assessment into perinatal care protocols holds promise in enhancing diagnostic precision. Growth velocity, involving changes in fetal size over a given period, offers insights into distinguishing between constitutional and pathological growth abnormalities. Various methodologies and models have been proposed to evaluate growth velocity, with notable advancements in understanding fetal growth patterns across different trimesters. It is believed that accelerated and reduced growth velocity may be a sensible parameter in the detection of fetal growth restriction (FGR), small-for-gestational-age (SGA) fetuses, large-for-gestational-age (LGA) fetuses and macrosomic fetuses as well as appropriate-for-gestational age (AGA) fetuses that encounter problems with growth continuation. Recent studies found that changes in growth velocity reflect the risk of adverse perinatal outcomes (APOs). Future directions in fetal health research aim to elucidate the long-term consequences of abnormal fetal growth velocity on neurodevelopmental outcomes, highlighting the critical role of early assessment and intervention.

Assessment of fetal growth trajectory identifies infants at high risk of perinatal mortality

OBJECTIVE

To analyze perinatal risks associated with three distinct scenarios of fetal growth trajectory in the latter half of pregnancy compared with a reference group.

METHODS

This cohort study included women with a singleton pregnancy that delivered between 32 + 0 and 41 + 6 weeks' gestation and had two or more ultrasound scans, at least 4 weeks apart, from 18 + 0 weeks. We evaluated three different scenarios of fetal growth against a reference group, which comprised appropriate-for-gestational-age fetuses with appropriate forward-growth trajectory. The comparator growth trajectories were categorized as: Group 1, small-for-gestational-age (SGA) fetuses (estimated fetal weight (EFW) or abdominal circumference (AC) persistently < 10th centile) with appropriate forward growth; Group 2, fetuses with decreased growth trajectory (decrease of ≥ 50 centiles) and EFW or AC ≥ 10th centile (i.e. non-SGA) at their final ultrasound scan; and Group 3, fetuses with decreased growth trajectory and EFW or AC < 10th centile (i.e. SGA) at their final scan. The primary outcome was overall perinatal mortality (stillbirth or neonatal death). Secondary outcomes included stillbirth, delivery of a SGA infant, preterm birth, emergency Cesarean section for non-reassuring fetal status and composite severe neonatal morbidity. Associations were analyzed using logistic regression.

RESULTS

The final study cohort comprised 5319 pregnancies. Compared to the reference group, the adjusted odds of perinatal mortality were increased significantly in Group 2 (adjusted odds ratio (aOR), 4.00 (95% CI, 1.36-11.22)) and Group 3 (aOR, 7.71 (95% CI, 2.39-24.91)). Only Group 3 had increased odds of stillbirth (aOR, 5.69 (95% CI, 1.55-20.93)). In contrast, infants in Group 1 did not have significantly increased odds of demise. The odds of a SGA infant at birth were increased in all three groups compared with the reference group, but was highest in Group 1 (aOR, 111.86 (95% CI, 62.58-199.95)) and Group 3 (aOR, 40.63 (95% CI, 29.01-56.92)). In both groups, more than 80% of infants were born SGA and nearly half had a birth weight < 3rd centile. Likewise, the odds of preterm birth were increased in all three groups compared with the reference group, being highest in Group 3, with an aOR of 4.27 (95% CI, 3.23-5.64). Lastly, the odds of composite severe neonatal morbidity were increased in Groups 1 and 3, whereas the odds of emergency Cesarean section for non-reassuring fetal status were increased only in Group 3.

CONCLUSION

Assessing the fetal growth trajectory in the latter half of pregnancy can help identify infants at increased risk of perinatal mortality and birth weight < 3rd centile for gestation. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Routine third-trimester ultrasound assessment for intrauterine growth restriction

Intrauterine growth restriction significantly impacts perinatal outcomes. Undetected IUGR escalates the risk of adverse outcomes. Serial symphysis-fundal height measurement, a recommended strategy, is insufficient in detecting abnormal fetal growth. Routine third-trimester ultrasounds significantly improve detection rates compared with this approach, but direct high-quality evidence supporting enhanced perinatal outcomes from routine scanning is lacking. In assessing fetal growth, abdominal circumference alone performs comparably to estimated fetal weight. Hadlock formulas demonstrate accurate fetal weight estimation across diverse gestational ages and settings. When choosing growth charts, prescriptive standards (encompassing healthy pregnancies) should be prioritized over descriptive ones. Customized fetal standards may enhance antenatal IUGR detection, but conclusive high-quality evidence is elusive. Emerging observational data suggest that longitudinal fetal growth assessment could predict adverse outcomes better. However, direct randomized trial evidence supporting this remains insufficient.

Placentae of small appropriately-grown-for-gestational-age neonates exhibit sexually dimorphic transcriptomic changes representative of placental insufficiency

INTRODUCTION

Previous studies have reported that neonates less than the 25th BWC especially if they were male, were more likely to be associated with birth complications suggesting small neonates often identified as appropriately grown are at risk of adverse outcomes. We have questioned whether smaller neonates not typically categorized as "small for gestational age" may not reach their genetically determined growth due to placental insufficiency.

METHODS

RNA-Seq was performed on the Illumina NovaSeq 600 using term placentae from neonates that were less than the 10th birthweight centile (BWC) (n = 39), between the 10th and the 30th BWC (n = 15) or greater than the 30th BWC (n = 23). Bioinformatic analyses were conducted and statistical significance was assessed at a level of P < 0.05 for single comparisons or FDR <0.05 unless otherwise noted.

RESULTS

Gene set enrichment analysis revealed differences between BWC groups and in relation to the sex of the placenta. Genes associated with hypoxia, inflammatory responses, estrogen responsive genes, and androgen responsive genes were enriched (FDR <0.1) for in placentae of neonates <10th BWC regardless of sex and also in male placentae of neonates between the 10th-30th BWC. Female placenta of neonates between the 10th-30th BWC were comparable to placentae of neonates >30th BWC.

DISCUSSION

These findings provide evidence that small male neonates may be at a greater risk of an adverse outcome than females due to changes in gene expression that are associated with placental dysfunction. The current data raises questions of whether placental pathology for smaller appropriately grown neonates should be scientifically and clinically examined in more depth.

Maternal sleep disordered breathing and offspring growth outcome: A systematic review and meta-analysis

Sleep disordered breathing is extremely common in pregnancy and is a risk factor for maternal complications. Animal models demonstrate that intermittent hypoxia causes abnormal fetal growth. However, there are conflicting data on the association between maternal sleep disordered breathing and offspring growth in humans. We investigated this association by conducting a systematic review and meta-analysis. Sixty-three manuscripts, and total study population of 67, 671, 110 pregnant women were included. Thirty-one studies used subjective methods to define sleep disordered breathing, 24 applied objective methods and eight used international codes. Using a random effects model, habitual snoring, defined by subjective methods, and obstructive sleep apnea, diagnosed by objective methods, were associated with an increased risk for large for gestational age (OR 1.46; 95%CI 1.02-2.09 and OR 2.19; 95%CI 1.63-2.95, respectively), while obstructive sleep apnea, identified by international codes, was associated with an increased risk for small for gestational age newborns (OR 1.28; 95%CI 1.02-1.60). Our results support that maternal sleep disordered breathing is associated with offspring growth, with differences related to the type of disorder and diagnostic methods used. Future studies should investigate underlying mechanisms and whether treatment of sleep disordered breathing ameliorates the neonatal growth.

Outcome-based comparative analysis of five fetal growth velocity models to define slow growth

OBJECTIVE

Fetal growth surveillance includes assessment of size as well as rate of growth, and various definitions for slow growth have been adopted into clinical use. The aim of this study was to evaluate the effectiveness of different models to identify stillbirth risk, in addition to risk represented by the fetus being small-for-gestational age (SGA).

METHODS

This was a retrospective analysis of a routinely collected and anonymized dataset of pregnancies that had two or more third-trimester ultrasound measurements of estimated fetal weight (EFW). SGA was defined as EFW < 10th customized centile, and slow growth was defined according to five published models in clinical use: (1) a fixed velocity limit of 20 g per day (FVL20 ); (2) a fixed > 50 centile drop, regardless of scan-measurement interval (FCD50 ); (3) a fixed > 30 centile drop, regardless of scan interval (FCD30 ); (4) growth trajectory slower than the third customized growth-centile limit (GCL3 ); and (5) EFW at second scan below the projected optimal weight range (POWR), based on partial receiver-operating-characteristics-curve-derived  cut-offs specific to the scan interval.

RESULTS

The study cohort consisted of 164 718 pregnancies with 480 592 third-trimester ultrasound scans (mean ± SD, 2.9 ± 0.9). The last two scans in each pregnancy were performed at an average gestational age of 33 + 5 and 37 + 1 weeks. At the last scan, 12 858 (7.8%) EFWs were SGA, and of these, 9359 were also SGA at birth (positive predictive value, 72.8%). The rate at which slow growth was defined varied considerably (FVL20 , 12.7%; FCD50 , 0.7%; FCD30 , 4.6%; GCL3 , 19.8%; POWR, 10.1%), and there was varying overlap between cases identified as having slow growth and those identified as SGA at the last scan. Only the POWR method identified additional non-SGA pregnancies with slow growth (11 237/16 671 (67.4%)) that had significant stillbirth risk (relative risk, 1.58 (95% CI, 1.04-2.39)). These non-SGA cases resulting in stillbirth had a median EFW centile of 52.6 at the last scan and a median weight centile of 27.3 at birth. Subgroup analysis identified methodological problems with the fixed-velocity model because it assumes linear growth throughout gestation, and with the centile-based methods because the non-parametric distribution of centiles at the extremes does not reflect actual difference in weight gain.

CONCLUSION

Comparative analysis of five clinically used methods to define slow fetal growth has shown that only the measurement-interval-specific POWR model can identify non-SGA fetuses with slow growth that are at increased risk of stillbirth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Predictive value of fetal growth trajectory from 20 weeks of gestation onwards for severe adverse perinatal outcome in low-risk population: secondary analysis of IRIS study

OBJECTIVES

The placental dysfunction underlying fetal growth restriction (FGR) may result in severe adverse perinatal outcome (SAPO) related to fetal hypoxia. Traditionally, the diagnostic criteria for FGR have been based on fetal size, an approach that is inherently flawed because it often results in either over- or underdiagnosis. The anomaly ultrasound scan at 20 weeks' gestation may be an appropriate time at which to set a benchmark for growth potential of the individual fetus. We hypothesized that the fetal growth trajectory from that point onwards may be informative regarding third-trimester placental dysfunction. The aim of this study was to investigate the predictive value for SAPO of a slow fetal growth trajectory between 18 + 0 to 23 + 6 weeks and 32 + 0 to 36 + 6 weeks' gestation in a large, low-risk population.

METHODS

This was a post-hoc data analysis of the IUGR Risk Selection (IRIS) study, a Dutch nationwide cluster-randomized trial assessing the (cost-)effectiveness of routine third-trimester sonography in reducing SAPO. In the current analysis, for the first ultrasound examination we used ultrasound data from the routine anomaly scan at 18 + 0 to 23 + 6 weeks' gestation, and for the second we used data from an ultrasound examination performed between 32 + 0 and 36 + 6 weeks' gestation. Using multilevel logistic regression, we analyzed whether SAPO was predicted by a slow fetal growth trajectory, which was defined as a decline in abdominal circumference (AC) and/or estimated fetal weight (EFW) of more than 20 percentiles or more than 50 percentiles or as an AC growth velocity (ACGV) < 10th percentile (p10). In addition, we analyzed the combination of these indicators of slow fetal growth with small-for-gestational age (SGA) (AC or EFW < p10) and severe SGA (AC/EFW < 3rd percentile) at 32 + 0 to 36 + 6 weeks' gestation.

RESULTS

Our sample included the data of 6296 low-risk singleton pregnancies, among which 82 (1.3%) newborns experienced at least one SAPO. Standalone declines in AC or EFW of > 20 or > 50 percentiles or ACGV < p10 were not associated with increased odds of SAPO. EFW < p10 between 32 + 0 and 36 + 6 weeks' gestation combined with a decline in EFW of > 20 percentiles was associated with an increased rate of SAPO. The combination of AC or EFW < p10 between 32 + 0 and 36 + 6 weeks' gestation with ACGV < p10 was also associated with increased odds of SAPO. The odds ratios of these associations were higher if the neonate was SGA at birth.

CONCLUSIONS

In a low-risk population, a slow fetal growth trajectory as a standalone criterion does not distinguish adequately between fetuses with FGR and those that are constitutionally small. This absence of association may be a result of diagnostic inaccuracies and/or post-diagnostic (e.g. intervention and selection) biases. We conclude that new approaches to detect placental insufficiency should integrate information from diagnostic tools such as maternal serum biomarkers and Doppler ultrasound measurements. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Stillbirth risk and smallness for gestational age according to Hadlock, INTERGROWTH-21st, WHO, and GROW fetal weight standards: analysis by maternal ethnicity and body mass index

BACKGROUND

Appropriate growth charts are essential for fetal surveillance, to confirm that growth is proceeding normally and to identify pregnancies that are at risk. Many stillbirths are avoidable through antenatal detection of the small-for-gestational-age fetus. In the absence of an international consensus on which growth chart to use, it is essential that clinical practice reflects outcome-based evidence.

OBJECTIVE

This study investigated the performance of 4 internationally used fetal weight standards and their ability to identify stillbirth risk in different ethnic and maternal size groups of a heterogeneous population.

STUDY DESIGN

We analyzed routinely collected maternity data from more than 2.2 million pregnancies. Three population-based fetal weight standards (Hadlock, Intergrowth-21st, and World Health Organization) were compared with the customized GROW standard that was adjusted for maternal height, weight, parity, and ethnic origin. Small-for-gestational-age birthweight and stillbirth risk were determined for the 2 largest ethnic groups in our population (British European and South Asian), in 5 body mass index categories, and in 4 maternal size groups with normal body mass index (18.5-25.0 kg/m2). The differences in trend between stillbirth and small-for-gestational-age rates were assessed using the Clogg z test, and differences between stillbirths and body mass index groups were assessed using the chi-square trend test.

RESULTS

Stillbirth rates (per 1000) were higher in South Asian pregnancies (5.51) than British-European pregnancies (3.89) (P<.01) and increased in both groups with increasing body mass index (P<.01). Small-for-gestational-age rates were 2 to 3-fold higher for South Asian babies than British European babies according to the population-average standards (Hadlock: 26.2% vs 12.2%; Intergrowth-21st: 12.1% vs 4.9%; World Health Organization: 32.2% vs 16.0%) but were similar by the customized GROW standard (14.0% vs 13.6%). Despite the wide variation, each standard's small-for-gestation-age cases had increased stillbirth risk compared with non-small-for-gestation-age cases, with the magnitude of risk inversely proportional to the rate of cases defined as small for gestational age. All standards had similar stillbirth risk when the small-for-gestation-age rate was fixed at 10% by varying their respective thresholds for defining small for gestational age. When analyzed across body mass index subgroups, the small-for-gestation-age rate according to the GROW standard increased with increasing stillbirth rate, whereas small-for-gestation-age rates according to Hadlock, Intergrowth-21st, and World Health Organization fetal weight standards declined with increasing body mass index, showing a difference in trend (P<.01) to stillbirth rates across body mass index groups. In the normal body mass index subgroup, stillbirth rates showed little variation across maternal size groups; this trend was followed by GROW-based small-for-gestation-age rates, whereas small-for-gestation-age rates defined by each population-average standard declined with increasing maternal size.

CONCLUSION

Comparisons between population-average and customized fetal growth charts require examination of how well each standard identifies pregnancies at risk of adverse outcomes within subgroups of any heterogeneous population. In both ethnic groups studied, increasing maternal body mass index was accompanied by increasing stillbirth risk, and this trend was reflected in more pregnancies being identified as small for gestational age only by the customized standard. In contrast, small-for-gestation-age rates fell according to each population-average standard, thereby hiding the increased stillbirth risk associated with high maternal body mass index.

Implication of third-trimester screening accuracy for small-for-gestational age and additive value of third-trimester growth-trajectory indicators in predicting severe adverse perinatal outcome in low-risk population: pragmatic secondary analysis of IRIS study

OBJECTIVES

To examine the implications of third-trimester small-for-gestational-age (SGA) screening accuracy on severe adverse perinatal outcome (SAPO) and obstetric intervention in a low-risk population. Furthermore, we aimed to explore the additive value of third-trimester sonographic growth-trajectory measurements in predicting SAPO and obstetric intervention.

METHODS

This was a secondary analysis of a Dutch national multicenter stepped-wedge-cluster randomized trial among 11 820 low-risk pregnant women. Using multilevel multivariable logistic regression analysis, we compared SAPO and obstetric interventions in SGA neonates with and without SGA suspected prenatally (true positives and false negatives) and non-SGA neonates with and without SGA suspected prenatally (false positives and true negatives). In a subsample (n = 7989), we analyzed the associations of abdominal circumference (AC) and estimated fetal weight (EFW) < 10th centile (p10) and third-trimester growth-trajectory indicators AC and EFW crossing > 20 and AC crossing > 50 centiles and the lowest decile of AC growth-velocity Z-scores (ACGV < 10%) with SAPO and obstetric interventions.

RESULTS

SGA infants, i.e. the true-positive and false-negative cases, had an increased risk of SAPO (adjusted odds ratio (aOR), 4.46 (95% CI, 2.28-8.75) and aOR 2.61 (95% CI, 1.74-3.89), respectively), and obstetric intervention (aOR for: induction of labor, 2.99 (95% CI, 2.15-4.17) and 1.38 (95% CI, 1.14-1.66); Cesarean section, 1.82 (95% CI, 1.25-2.66) and 1.27 (95% CI, 1.05-1.54); medically indicated preterm delivery, 2.67 (95% CI, 1.97-3.62) and 1.20 (95% CI, 1.03-1.40)). The false-positive cases did not differ from the true negatives for all outcomes, including obstetric intervention. Of the third-trimester growth-trajectory indicators, only ACGV < 10% was associated moderately with SAPO (aOR, 2.15 (95% CI, 1.17-3.97)), while AC and EFW crossing > 20 and AC crossing > 50 centiles were not. Both EFW < p10 alone (aOR, 1.95 (95% CI, 1.13-3.38)) and EFW < p10 combined with ACGV < 10% (aOR, 4.69 (95% CI, 1.99-11.07)) were associated with SAPO, and they performed equally well in predicting SAPO (area under the receiver-operating-characteristics curve, 0.71 (95% CI, 0.65-0.76) vs 0.72 (95% CI, 0.67-0.77), P = 0.51).

CONCLUSION

Neonates who had been suspected falsely of being SGA during pregnancy had no higher rates of obstetric intervention than did those without suspicion of SGA prenatally. Our results do not support that third-trimester low fetal growth velocity (ACGV < 10%) may be of additive value for the identification of fetuses at risk of SAPO in populations remaining at low risk throughout pregnancy. AC and EFW crossing > 20 and AC crossing > 50 centiles performed poorly in identifying abnormal fetal growth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Growth Velocity according to the Mode of Assisted Conception

INTRODUCTION

Pregnancies conceived through assisted reproductive techniques (ARTs) are on the rise worldwide and have been associated with a higher risk of placental-related disease in the third trimester.

METHODS

A cohort was created of singleton pregnancies after assisted reproduction, admitted at our institution for delivery, between January 2020 and August 2022. Fetal growth velocity from the second trimester to delivery was compared against a gestational-age-matched group of pregnancies spontaneously conceived according to the origin of the selected oocyte (i.e., autologous vs. donated).

RESULTS

125 singleton pregnancies conceived through ART were compared to 315 singleton spontaneous conceptions. Overall, after adjusting for possible confounders, multivariate analysis demonstrated that ART pregnancies had a significantly lower estimated fetal weight (EFW) z-velocity from the second trimester to delivery (adjusted mean difference = -0.002; p = 0.035) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 2.32 [95% CI, 1.15-4.68]). Also, when ART pregnancies were compared according to the type of oocyte, those conceived with donated oocytes showed a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference = -0.008; p = 0.001) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 5.33 [95% CI, 1.34-21.5]).

CONCLUSIONS

Pregnancies achieved through ART exhibit a pattern of lower growth velocity across the third trimester, especially those conceived with donated oocytes. The former represents a sub-group at the highest risk of placental dysfunction that may warrant closer follow-up.

Evaluating the Growth Assessment Protocol for stillbirth prevention: progress and challenges

Many stillbirths are associated with fetal growth restriction, and are hence potentially avoidable. The Growth Assessment Protocol (GAP) is a multidisciplinary program with an evidence based care pathway, training in risk assessment, fetal growth surveillance with customised charts and rolling audit. Antenatal detection of small for gestational age (SGA) has become an indicator of quality of care. Evaluation is essential to understand the impact of such a prevention program. Randomised trials will not be effective if they cannot ensure proper implementation before assessment. Observational studies have allowed realistic evaluation in practice, with other factors excluded that may have influenced the outcome. An award winning 10 year study of stillbirth data in England has been able to assess the effect of GAP in isolation, and found a strong, causal association with improved antenatal detection of SGA babies, and the sustained decline in national stillbirth rates. The challenge now is to apply this program more widely in low and middle income settings where the main global burden of stillbirth is, and to adapt it to local needs and resources.