Fetal growth and risk of stillbirth: a population-based case-control study

Stillbirth: we can do better

Stillbirth is far too common, occurring in millions of pregnancies per year globally. The rate of stillbirth (defined as death of a fetus prior to birth at 20 weeks' gestation or more) in the United States is 5.73 per 1000. This is approximately 1 in 175 pregnancies accounting for about 21,000 stillbirths per year. Although rates are much higher in low-income countries, the stillbirth rate in the United States is much higher than most high resource countries. Moreover, there are substantial disparities in stillbirth, with rates twice as high for non-Hispanic Black and Native Hawaiian or Other Pacific Islanders compared to non-Hispanic Whites. There is considerable opportunity for reduction in stillbirths, even in high resource countries such as the United States. In this article, we review the epidemiology, risk factors, causes, evaluation, medical and emotional management, and prevention of stillbirth. We focus on novel data regarding genetic etiologies, placental assessment, risk stratification, and prevention.

Stillbirth risk by fetal size among 126.5 million births in 15 countries from 2000 to 2020: A fetuses-at-risk approach

OBJECTIVE

To compare stillbirth rates and risks for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) pregnancies at 24-44 completed weeks of gestation using a birth-based and fetuses-at-risk approachs.

DESIGN

Population-based, multi-country study.

SETTING

National data systems in 15 high- and middle-income countries.

POPULATION

Live births and stillbirths.

METHODS

A total of 151 country-years of data, including 126 543 070 births across 15 countries from 2000 to 2020, were compiled. Births were categorised into SGA, AGA and LGA using INTERGROWTH-21st standards. Gestation-specific stillbirth rates, with total births as the denominator, and gestation-specific stillbirth risks, with fetuses still in utero as the denominator, were calculated from 24 to 44 weeks of gestation.

MAIN OUTCOME MEASURES

Gestation-specific stillbirth rates and risks according to size at birth.

RESULTS

The overall stillbirth rate was 4.22 per 1000 total births (95% CI 4.22-4.23) across all gestations. Applying the birth-based approach, the stillbirth rates were highest at 24 weeks of gestation, with 621.6 per 1000 total births (95% CI 620.9-622.2) for SGA pregnancies, 298.4 per 1000 total births (95% CI 298.1-298.7) for AGA pregnancies and 338.5 per 1000 total births (95% CI 337.9-339.0) for LGA pregnancies. Applying the fetuses-at-risk approach, the gestation-specific stillbirth risk was highest for SGA pregnancies (1.3-1.4 per 1000 fetuses at risk) prior to 29 weeks of gestation. The risk remained stable between 30 and 34 weeks of gestation, and then increased gradually from 35 weeks of gestation to the highest rate of 8.4 per 1000 fetuses at risk (95% CI 8.3-8.4) at ≥42 weeks of gestation. The stillbirth risk ratio (RR) was consistently high for SGA compared with AGA pregnancies, with the highest RR observed at ≥42 weeks of gestation (RR 9.2, 95% CI 15.2-13.2), and with the lowest RR observed at 24 weeks of gestation (RR 3.1, 95% CI 1.9-4.3). The stillbirth RR was also consistently high for SGA compared with AGA pregnancies across all countries, with national variability ranging from RR 0.70 (95% CI 0.43-0.97) in Mexico to RR 8.6 (95% CI 8.1-9.1) in Uruguay. No increased risk for LGA pregnancies was observed.

CONCLUSIONS

Small for gestational age (SGA) was strongly associated with stillbirth risk in this study based on high-quality data from high- and middle-income countries. The highest RRs were seen in preterm gestations, with two-thirds of the stillbirths born as preterm births. To advance our understanding of stillbirth, further analyses should be conducted using high-quality data sets from low-income settings, particularly those with relatively high rates of SGA.

The impact of impaired intrauterine growth on male fertility: A systematic review and meta-analysis

BACKGROUND

Adverse intrauterine environment was believed to have deleterious effects on the gonadal function. However, the association between impaired intrauterine growth and fertility in adult males has not been established.

OBJECTIVES

To compare the reproductive rates of males born small for gestational age (SGA), with low birth weight (LBW) or very low birth weight (VLBW) with control groups.

METHODS

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was followed to search PubMed, Web of Science, Cochrane Library, and Embase databases from inception to June 16, 2023. Cohort studies investigating the reproductive rates of males born SGA, with LBW or VLBW were included. A random or fixed effects model was used for different exposures.

RESULTS

A total of 10 studies out of 3,801 records were included. Males born SGA showed a higher risk of infertility than the control group (odds ratio, OR = 0.91, 95% confidence interval, 95% CI 0.89-0.93, p = 0.000). The reproductive rates of individuals born with LBW or VLBW were lower than the control group (OR = 0.86, 95% CI 0.78-0.94, p = 0.001; OR = 0.57, 95% CI 0.40-0.81, p = 0.002, respectively). Participants were further divided into two age groups of 18-35 and 35-45 years. In both subgroups, the reproductive rates were lower in males born SGA, with LBW or VLBW compared with controls. Sensitivity analysis showed the robustness of the pooled estimates among LBW and VLBW.

CONCLUSION

In summary, SGA, LBW, and VLBW were associated with a higher risk of male infertility in both early and middle adulthood. Achieving optimal intrauterine growth would be helpful to prevent male infertility.

Placental somatic mutation in human stillbirth and live birth: A pilot case-control study of paired placental, fetal, and maternal whole genomes

INTRODUCTION

A high frequency of single nucleotide somatic mutations in the placenta has been recently described, but its relationship to placental dysfunction is unknown.

METHODS

We performed a pilot case-control study using paired fetal, maternal, and placental samples collected from healthy live birth controls (n = 10), live births with fetal growth restriction (FGR) due to placental insufficiency (n = 7), and stillbirths with FGR and placental insufficiency (n = 11). We quantified single nucleotide and structural somatic variants using bulk whole genome sequencing (30-60X coverage) in four biopsies from each placenta. We also assessed their association with clinical and histological evidence of placental dysfunction.

RESULTS

Seventeen pregnancies had sufficiently high-quality placental, fetal, and maternal DNA for analysis. Each placenta had a median of 473 variants (range 111-870), with 95 % arising in just one biopsy within each placenta. In controls, live births with FGR, and stillbirths, the median variant counts per placenta were 514 (IQR 381-779), 582 (450-735), and 338 (245-441), respectively. After adjusting for depth of sequencing coverage and gestational age at birth, the somatic mutation burden was similar between groups (FGR live births vs. controls, adjusted diff. 59, 95 % CI -218 to +336; stillbirths vs controls, adjusted diff. -34, -351 to +419), and with no association with placental dysfunction (p = 0.7).

DISCUSSION

We confirmed the high prevalence of somatic mutation in the human placenta and conclude that the placenta is highly clonal. We were not able to identify any relationship between somatic mutation burden and clinical or histologic placental insufficiency.

Development and evaluation of machine learning models for predicting large-for-gestational-age newborns in women exposed to radiation prior to pregnancy

INTRODUCTION

The correlation between radiation exposure before pregnancy and abnormal birth weight has been previously proven. However, for large-for-gestational-age (LGA) babies in women exposed to radiation before becoming pregnant, there is no prediction model yet.

MATERIAL AND METHODS

The data were collected from the National Free Preconception Health Examination Project in China. A sum of 455 neonates (42 SGA births and 423 non-LGA births) were included. A training set (n = 319) and a test set (n = 136) were created from the dataset at random. To develop prediction models for LGA neonates, conventional logistic regression (LR) method and six machine learning methods were used in this study. Recursive feature elimination approach was performed by choosing 10 features which made a big contribution to the prediction models. And the Shapley Additive Explanation model was applied to interpret the most important characteristics that affected forecast outputs.

RESULTS

The random forest (RF) model had the highest average area under the receiver-operating-characteristic curve (AUC) for predicting LGA in the test set (0.843, 95% confidence interval [CI]: 0.714-0.974). Except for the logistic regression model (AUC: 0.603, 95%CI: 0.440-0.767), other models' AUCs displayed well. Thereinto, the RF algorithm's final prediction model using 10 characteristics achieved an average AUC of 0.821 (95% CI: 0.693-0.949).

CONCLUSION

The prediction model based on machine learning might be a promising tool for the prenatal prediction of LGA births in women with radiation exposure before pregnancy.

Maternal tadalafil treatment does not increase uterine artery blood flow or oxygen delivery in the pregnant ewe

Increasing placental perfusion (PP) could improve outcomes of growth-restricted fetuses. One way of increasing PP may be by using phosphodiesterase (PDE)-5 inhibitors, which induce vasodilatation of vascular beds. We used a combination of clinically relevant magnetic resonance imaging (MRI) techniques to characterize the impact that tadalafil infusion has on maternal, placental and fetal circulations. At 116-117 days' gestational age (dGA; term, 150 days), pregnant ewes (n = 6) underwent fetal catheterization surgery. At 120-123 dGA ewes were anaesthetized and MRI scans were performed during three acquisition windows: a basal state and then ∼15-75 min (TAD 1) and ∼75-135 min (TAD 2) post maternal administration (24 mg; intravenous bolus) of tadalafil. Phase contrast MRI and T2 oximetry were used to measure blood flow and oxygen delivery. Placental diffusion and PP were assessed using the Diffusion-Relaxation Combined Imaging for Detailed Placental Evaluation-'DECIDE' technique. Uterine artery (UtA) blood flow when normalized to maternal left ventricular cardiac output (LVCO) was reduced in both TAD periods. DECIDE imaging found no impact of tadalafil on placental diffusivity or fetoplacental blood volume fraction. Maternal-placental blood volume fraction was increased in the TAD 2 period. FetalD O 2 ${D_{{{\mathrm{O}}_2}}}$ andV ̇ O 2 ${\dot V_{{{\mathrm{O}}_2}}}$ were not affected by maternal tadalafil administration. Maternal tadalafil administration did not increase UtA blood flow and thus may not be an effective vasodilator at the level of the UtAs. The increased maternal-placental blood volume fraction may indicate local vasodilatation of the maternal intervillous space, which may have compensated for the reduced proportion of UtAD O 2 ${D_{{{\mathrm{O}}_2}}}$ .

Large for Gestational Age and Adverse Outcomes: Stratified By Diabetes Status

OBJECTIVE

 To examine the association of adverse outcomes among parturients with large for gestational age (LGA; birth weight ≥ 90th) newborns, stratified by diabetes status. Additionally, we described the temporal trends of adverse outcomes among LGA neonates.

STUDY DESIGN

 This retrospective cohort study used the U.S. Vital Statistics dataset between 2014 and 2020. The inclusion criteria were singleton, nonanomalous LGA live births who labored and delivered at 24 to 41 weeks with known diabetes status. The coprimary outcomes were composite neonatal adverse outcomes of the following: Apgar score < 5 at 5 minutes, assisted ventilation > 6 hours, seizure, or neonatal or infant mortality, and maternal adverse outcomes of the following: maternal transfusion, ruptured uterus, unplanned hysterectomy, admission to intensive care unit, or unplanned procedure. Multivariable Poisson regression models were used to estimate adjusted relative risks (aRR) and 95% confidence intervals (CI). Average annual percent change (AAPC) was calculated to assess changes in rates of LGA and morbidity over time.

RESULTS

 Of 27 million births in 7 years, 1,843,467 (6.8%) met the inclusion criteria. While 1,656,888 (89.9%) did not have diabetes, 186,579 (10.1%) were with diabetes. Composite neonatal adverse outcomes (aRR = 1.48, 95% CI = 1.43, 1.52) and composite maternal adverse outcomes (aRR = 1.37, 95% CI = 1.36, 1.38) were significantly higher among individuals with diabetes, compared with those without diabetes. From 2014 to 2020, the LGA rate was stable among people without diabetes. However, there was a downward trend of LGA in people with diabetes (AAPC = - 2.4, 95% CI = - 3.5, -1.4).

CONCLUSION

 In pregnancies with LGA newborns, composite neonatal and maternal morbidities were higher in those with diabetes, compared with those without diabetes.

KEY POINTS

· Large for gestational age stratified by diabetes status.. · Composite neonatal and maternal adverse outcomes are worse among individuals with diabetes as compared to those without.. · During 2014 to 2020, the trend of LGA in individuals without diabetes increased..

Prevalence and risk of stillbirth according to biologic vulnerability phenotypes in the municipality of São Paulo, Brazil: A population-based cohort study

OBJECTIVE

To estimate the prevalence and risk of stillbirths by biologic vulnerability phenotypes in a cohort of pregnant women in the municipality of São Paulo, Brazil, 2017-2019.

METHODS

Retrospective population-based cohort study. Fetuses were assessed as small for gestational age (SGA), large for gestational age (LGA), adequate for gestational age (AGA), preterm (PT) as less than 37 weeks of gestation, non-PT (NPT) as 37 weeks of gestation or more, low birth weight (LBW) as less than 2500 g, and non-LBW (NLBW) as 2500 g or more. Relative risks (RR) with robust variance were estimated using Poisson regression.

RESULTS

In all 442 782 pregnancies, including 2321 (0.5%) stillbirths, were included. About 85% (n = 1983) of stillbirths had at least one characteristic of vulnerability, compared with 21% (n = 92524) of live births. Fetuses with all three markers of vulnerability had the highest adjusted RR of stillbirth-SGA + LBW + PT (RR 155.00; 95% confidence interval [CI] 136.29-176.30) and LGA + LBW + PT (RR 262.04; 95% CI 206.10-333.16) when compared with AGA + NLBW + NPT.

CONCLUSION

Our findings show that the simultaneous presence of prematurity, low birth weight, and abnormal intrauterine growth presented a higher risk of stillbirths. To accelerate progress towards reducing preventable stillbirths, one must identify the circumstances of greatest biologic vulnerability.

DLK1: A Novel Biomarker of Placental Insufficiency in Stillbirth and Live Birth

OBJECTIVE

Delta-like homolog 1 (DLK1) is a growth factor that is reduced in maternal sera in pregnancies with small for gestational age neonates. We sought to determine if DLK1 is associated with stillbirth (SB), with and without placental insufficiency.

STUDY DESIGN

A nested case-control study was performed using maternal sera from a multicenter case-control study of SB and live birth (LB). SB and LB were stratified as placental insufficiency cases (small for gestational age <5% or circulatory lesions on placental histopathology) or normal placenta controls (appropriate for gestational age and no circulatory lesions). Enzyme-linked immunosorbent assay (ELISA) was used to measure DLK1. The mean difference in DLK1 was compared on the log scale in an adjusted linear regression model with pairwise differences, stratified by term/preterm deliveries among DLK1 results in the quantifiable range. In exploratory analysis, geometric means were compared among all data and the proportion of "low DLK1" (less than the median value for gestational age) was compared between groups and modeled using linear and logistic regression, respectively.

RESULTS

Overall, 234 SB and 234 LB were analyzed; 246 DLK1 values were quantifiable within the standard curve. Pairwise comparisons of case and control DLK1 geometric means showed no significant differences between groups. In exploratory analysis of all data, adjusted analysis revealed a significant difference for the LB comparison only (SB: 71.9 vs. 99.1 pg/mL, p = 0.097; LB: 37.6 vs. 98.1 pg/mL, p = 0.005). In exploratory analysis of "low DLK1," there was a significant difference between the odds ratio of having "low DLK1" between preterm cases and controls for both SB and LB. There were no significant differences in geometric means nor "low DLK1" between SB and LB.

CONCLUSION

In exploratory analysis, more placental insufficiency cases in preterm SB and LB had "low DLK1." However, low DLK1 levels were not associated with SB.

KEY POINTS

· Maternally circulating DLK1 is correlated with placental insufficiency.. · Maternally circulating DLK1 is not correlated with SB.. · DLK1 is a promising marker for placental insufficiency..

Improved estimation of the relationship between fetal growth and late stillbirth in the United States, 2014-15

In the United States the rate of stillbirth after 28 weeks' gestation (late stillbirth) is 2.7/1000 births. Fetuses that are small for gestational age (SGA) or large for gestational age (LGA) are at increased risk of stillbirth. SGA and LGA are often categorized as growth or birthweight ≤ 10th and ≥ 90th centile, respectively; however, these cut-offs are arbitrary. We sought to characterize the relationship between birthweight and stillbirth risk in greater detail. Data on singleton births between 28- and 44-weeks' gestation from 2014 to 2015 were extracted from the US Centers for Disease Control and Prevention live birth and fetal death files. Growth was assessed using customized birthweight centiles (Gestation Related Optimal Weight; GROW). The analyses included logistic regression using SGA/LGA categories and a generalized additive model (GAM) using birthweight centile as a continuous exposure. Although the SGA and LGA categories identified infants at risk of stillbirth, categorical models provided poor fits to the data within the high-risk bins, and in particular markedly underestimated the risk for the extreme centiles. For example, for fetuses in the lowest GROW centile, the observed rate was 39.8/1000 births compared with a predicted rate of 11.7/1000 from the category-based analysis. In contrast, the model-predicted risk from the GAM tracked closely with the observed risk, with the GAM providing an accurate characterization of stillbirth risk across the entire birthweight continuum. This study provides stillbirth risk estimates for each GROW centile, which clinicians can use in conjunction with other clinical details to guide obstetric management.

Postpartum readmission risk: a comparison between stillbirths and live births

BACKGROUND

Stillbirth occurs more commonly among pregnant people with comorbid conditions and obstetrical complications. Stillbirth also independently increases maternal morbidity and imparts a psychosocial hazard when compared with live birth. These distinct needs and burden may increase the risk for postpartum readmission after stillbirth.

OBJECTIVE

This study aimed to examine the risk for maternal postpartum readmission after stillbirth in comparison with live birth and to identify indications for readmission and the associated risk factors.

STUDY DESIGN

This was a retrospective cohort of patients with singleton stillbirths or live births, delivered at ≥20 weeks' gestation, who were identified from the 2019 Nationwide Readmissions Database. The primary outcome was all-cause readmission within 6 weeks of discharge from the childbirth hospitalization. The association between stillbirth (vs live birth) and risk for readmission was assessed using multivariable regression models with adjustment for maternal age, sociodemographic characteristics, maternal and obstetrical conditions, and delivery characteristics. Within the stillbirth group, risk factors for readmission were further examined using multivariable regression. The secondary outcomes included principal indication for readmission (categorized based on principal diagnosis code of the readmission hospitalization) and timing of readmission (number of weeks after childbirth hospitalization). Differences in these secondary outcomes were compared between the stillbirth and live birth groups using chi-square tests. All analyses accounted for the complex sample design to generate nationally representative estimates.

RESULTS

Postpartum readmission occurred in 2.7% of 16,636 patients with stillbirths, whereas it occurred in 1.6% of 2,870,677 patients with live births (unadjusted risk ratio, 1.65; 95% confidence interval, 1.47-1.86). The higher risk for readmission after stillbirth (vs live birth) persisted after adjusting for maternal, obstetrical, and delivery characteristics (adjusted risk ratio, 1.27; 95% confidence interval, 1.11-1.46). The distribution of principal indication for readmission differed after stillbirth and after live birth and included hypertension (30.2% vs 39.5%; unadjusted risk ratio, 0.76; 95% confidence interval, 0.63-0.93), mental health or substance use disorders (6.8% vs 3.6%; unadjusted risk ratio, 1.90; 95% confidence interval, 1.15-3.16), and venous thromboembolism (5.8% vs 2.0%; unadjusted risk ratio, 2.87; 95% confidence interval, 1.60-5.17). Among patients with stillbirths, 56.0% of readmissions occurred within 1 week, 71.8% within 2 weeks, and 88.1% within 4 weeks; the timing of readmission did not differ significantly between the stillbirth and live birth cohorts. Pregestational diabetes (adjusted risk ratio, 1.87; 95% confidence interval, 1.20-2.93), gestational diabetes (adjusted risk ratio, 1.67; 95% confidence interval, 1.03-2.71), hypertensive disorders of pregnancy (adjusted risk ratio, 1.80; 95% confidence interval, 1.31-2.47), obesity (adjusted risk ratio, 1.46; 95% confidence interval, 1.01-2.12), and primary cesarean delivery (adjusted risk ratio, 1.74; 95% confidence interval, 1.17-2.58) were associated with a higher risk for readmission after stillbirth, whereas higher household income was associated with a lower risk for readmission (eg, adjusted risk ratio for income ≥$82,000 vs $1-$47,999, 0.48; 95% confidence interval, 0.30-0.77).

CONCLUSION

When compared with live births, the risk for postpartum readmission was higher after stillbirths, even after adjustment for differences in the patient demographic and clinical characteristics. Readmission for mental health or substance use disorders and venous thromboembolism is more common after stillbirths than after live births.

Predicting and preventing stillbirth at term

Stillbirth at term affects ∼1 per 1000 pregnancies at term in high income countries. A range of maternal characteristics are associated with stillbirth risk. However, given the low a priori risk of stillbirth, the vast majority of women with clinical risk factors would not experience a stillbirth in the absence of intervention. Stillbirth is the end point of multiple pathways, including both fetal growth restriction and fetal overgrowth. In most term stillbirths there is no mechanistic understanding of the cause of death and a sizeable proportion are completely unexplained. Term stillbirth is potentially preventable by early delivery, providing a rationale for screening. "Omic" analyses of blood taken prior to the onset of some of the conditions associated with stillbirth may help identify women at high risk and allow the potentially harmful intervention of early term medically indicated delivery to be targeted to the pregnancies most likely to benefit.

No major differences in perinatal and maternal outcomes between uninterrupted embryo culture in time-lapse system and conventional embryo culture

STUDY QUESTION

Is embryo culture in a closed time-lapse system associated with any differences in perinatal and maternal outcomes in comparison to conventional culture and spontaneous conception?

SUMMARY ANSWER

There were no significant differences between time-lapse and conventional embryo culture in preterm birth (PTB, <37 weeks), low birth weight (LBW, >2500 g) and hypertensive disorders of pregnancy for singleton deliveries, the primary outcomes of this study.

WHAT IS KNOWN ALREADY

Evidence from prospective trials evaluating the safety of time-lapse incubation for clinical use show similar embryo development rates, implantation rates, and ongoing pregnancy and live birth rates when compared to conventional incubation. Few studies have investigated if uninterrupted culture can alter risks of adverse perinatal outcomes presently associated with IVF when compared to conventional culture and spontaneous conceptions.

STUDY DESIGN, SIZE, DURATION

This study is a Swedish population-based retrospective registry study, including 7379 singleton deliveries after fresh embryo transfer between 2013 and 2018 from selected IVF clinics. Perinatal outcomes of singletons born from time-lapse-cultured embryos were compared to singletons from embryos cultured in conventional incubators and 71 300 singletons from spontaneous conceptions. Main perinatal outcomes included PTB and LBW. Main maternal outcomes included hypertensive disorders of pregnancy (pregnancy hypertension and preeclampsia).

PARTICIPANTS/MATERIALS, SETTING, METHODS

From nine IVF clinics, 2683 singletons born after fresh embryo transfer in a time-lapse system were compared to 4696 singletons born after culture in a conventional incubator and 71 300 singletons born after spontaneous conception matched for year of birth, parity, and maternal age. Patient and treatment characteristics from IVF deliveries were cross-linked with the Swedish Medical Birth Register, Register of Birth Defects, National Patient Register and Statistics Sweden. Children born after sperm and oocyte donation cycles and after Preimplantation Genetic testing cycles were excluded. Odds ratio (OR) and adjusted OR were calculated, adjusting for relevant confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

In the adjusted analyses, no significant differences were found for risk of PTB (adjusted OR 1.11, 95% CI 0.87-1.41) and LBW (adjusted OR 0.86, 95% CI 0.66-1.14) or hypertensive disorders of pregnancy; preeclampsia and hypertension (adjusted OR 0.99, 95% CI 0.67-1.45 and adjusted OR 0.98, 95% CI 0.62-1.53, respectively) between time-lapse and conventional incubation systems. A significantly increased risk of PTB (adjusted OR 1.31, 95% CI 1.08-1.60) and LBW (adjusted OR 1.36, 95% CI 1.08-1.72) was found for singletons born after time-lapse incubation compared to singletons born after spontaneous conceptions. In addition, a lower risk for pregnancy hypertension (adjusted OR 0.72 95% CI 0.53-0.99) but no significant difference for preeclampsia (adjusted OR 0.87, 95% CI 0.68-1.12) was found compared to spontaneous conceptions. Subgroup analyses showed that some risks were related to the day of embryo transfer, with more adverse outcomes after blastocyst transfer in comparison to cleavage stage transfer.

LIMITATIONS, REASONS FOR CAUTION

This study is retrospective in design and different clinical strategies may have been used to select specific patient groups for time-lapse versus conventional incubation. The number of patients is limited and larger datasets are required to obtain more precise estimates and adjust for possible effect of additional embryo culture variables.

WIDER IMPLICATIONS OF THE FINDINGS

Embryo culture in time-lapse systems is not associated with major differences in perinatal and maternal outcomes, compared to conventional embryo culture, suggesting that this technology is an acceptable alternative for embryo incubation.

STUDY FUNDING/COMPETING INTEREST(S)

The study was financed by a research grant from Gedeon Richter. There are no conflicts of interest for all authors to declare.

TRIAL REGISTRATION NUMBER

N/A.

Abdominal circumference growth velocity as a predictor of adverse perinatal outcomes in small-for-gestational-age fetuses

OBJECTIVE

To assess the predictive value of abdominal circumference growth velocity (ACGV) between the second and third trimesters to predict adverse perinatal outcomes in a cohort of small-for-gestational-age fetuses without evidence of placental insufficiency (i.e. fetal growth restriction).

MATERIAL AND METHODS

This is a single-center retrospective cohort study of all singleton pregnancies with small-for-gestational-age fetuses diagnosed and delivered at a quaternary institution. Crude and adjusted odds ratios (ORs) and corresponding confidence intervals (CIs) were calculated via logistic regression models to assess the potential association between abnormal ACGV (i.e. ≤10th centile) and adverse perinatal outcomes defined as a composite outcome (i.e. umbilical artery pH <7.1, 5-min Apgar score <7, admission to the neonatal intensive care unit, hypoglycemia, intrapartum fetal distress requiring expedited delivery, and perinatal death). Furthermore, the area under the receiver-operating characteristic curve (AUC) of three logistic regression models based on estimated fetal weight and ACGV for predicting the composite outcome is also reported.

RESULTS

A total of 154 pregnancies were included for analysis. The median birthweight for the cohort was 2,437 g (interquartile range [IQR] 2280, 2635). Overall, the primary composite outcome was relatively common (29.2%). In addition, there was a significant association between abnormal ACGV and adverse perinatal outcomes (OR 3.37, 95% CI 1.60, 7.13; adjusted OR 4.30, 95% CI 1.77, 10.49). Likewise, the AUC for the ACGV was marginally higher (0.64) than the estimated fetal weight (0.54) and ACGV + estimated fetal weight (0.54). Still, no significant difference was detected between the curves (p = 0.297).

CONCLUSIONS

Our results suggest that an ACGV below the 10th centile is a risk factor for adverse perinatal outcomes among small-for-gestational-age fetuses.

Insufficient antenatal identification of fetal growth restriction leading to intrauterine fetal death: a regional population-based study in Japan

OBJECTIVE

Fetal growth restriction (FGR) is associated with perinatal adverse outcomes including intrauterine fetal death. Antenatally unidentified FGR has a higher risk of intrauterine fetal death than that identified antenatally. We, therefore, investigated the antenatal identification of FGR among intrauterine fetal deaths, and assessed the perinatal factors associated with the identification of FGR.

METHODS

This retrospective and population-based study reviewed all stillbirths in Shiga Prefecture, Japan, from 2007 to 2016 with exclusion criteria of multiple births, births at unidentified gestational weeks or < 22 gestational weeks, and lethal disorders. We analyzed cases of FGR, using the Japanese clinical definition: Z-score of estimated fetal weight for gestational age <-1.5 standard deviations (SD).

RESULTS

We identified 94 stillbirths with FGR among 429 stillbirths. Thirty-seven cases were antenatally identified during pregnancy management (39%). Dividing cases by a Z-score of -2.5 SD, 51 cases were classified as ≤-2.5 SD. Twenty-eight of the 51 cases (55%) with a Z-score <-2.5 SD were antenatally identified as having FGR, whereas 9 of the 43 cases (21%) with a Z-score ≥-2.5 SD were antenatally identified as having FGR (p = .002). Among cases with a Z-Score <-2.5 SD, 16 of 21 (76%) beyond 28 weeks' gestation and 12 of 30 (40%) before 28weeks' gestation were antenatally identified as having FGR (p = .023).

CONCLUSION

Fetal growth restriction leading to intrauterine fetal death in Japan was antenatally identified in less than half of cases. Antenatal identification of FGR was associated with the severity of growth restriction.

Stillbirths: Contribution of preterm birth and size-for-gestational age for 125.4 million total births from nationwide records in 13 countries, 2000-2020

OBJECTIVE

To examine the contribution of preterm birth and size-for-gestational age in stillbirths using six 'newborn types'.

DESIGN

Population-based multi-country analyses.

SETTING

Births collected through routine data systems in 13 countries.

SAMPLE

125 419 255 total births from 22+0 to 44+6 weeks' gestation identified from 2000 to 2020.

METHODS

We included 635 107 stillbirths from 22+0  weeks' gestation from 13 countries. We classified all births, including stillbirths, into six 'newborn types' based on gestational age information (preterm, PT, <37+0  weeks versus term, T, ≥37+0  weeks) and size-for-gestational age defined as small (SGA, <10th centile), appropriate (AGA, 10th-90th centiles) or large (LGA, >90th centile) for gestational age, according to the international newborn size for gestational age and sex INTERGROWTH-21st standards.

MAIN OUTCOME MEASURES

Distribution of stillbirths, stillbirth rates and rate ratios according to six newborn types.

RESULTS

635 107 (0.5%) of the 125 419 255 total births resulted in stillbirth after 22+0  weeks. Most stillbirths (74.3%) were preterm. Around 21.2% were SGA types (PT + SGA [16.2%], PT + AGA [48.3%], T + SGA [5.0%]) and 14.1% were LGA types (PT + LGA [9.9%], T + LGA [4.2%]). The median rate ratio (RR) for stillbirth was highest in PT + SGA babies (RR 81.1, interquartile range [IQR], 68.8-118.8) followed by PT + AGA (RR 25.0, IQR, 20.0-34.3), PT + LGA (RR 25.9, IQR, 13.8-28.7) and T + SGA (RR 5.6, IQR, 5.1-6.0) compared with T + AGA. Stillbirth rate ratios were similar for T + LGA versus T + AGA (RR 0.7, IQR, 0.7-1.1). At the population level, 25% of stillbirths were attributable to small-for-gestational-age.

CONCLUSIONS

In these high-quality data from high/middle income countries, almost three-quarters of stillbirths were born preterm and a fifth small-for-gestational age, with the highest stillbirth rates associated with the coexistence of preterm and SGA. Further analyses are needed to better understand patterns of gestation-specific risk in these populations, as well as patterns in lower-income contexts, especially those with higher rates of intrapartum stillbirth and SGA.

Risk factors for late (28+ weeks' gestation) stillbirth in the United States, 2014-2015

BACKGROUND

In the United States (US) late stillbirth (at 28 weeks or more of gestation) occurs in 3/1000 births.

AIM

We examined risk factors for late stillbirth with the specific goal of identifying modifiable factors that contribute substantially to stillbirth burden.

SETTING

All singleton births in the US for 2014-2015.

METHODS

We used a retrospective population-based design to assess the effects of multiple factors on the risk of late stillbirth in the US. Data were drawn from the US Centers for Disease Control and Prevention live birth and fetal death data files.

RESULTS

There were 6,732,157 live and 18,334 stillbirths available for analysis (late stillbirth rate = 2.72/1000 births). The importance of sociodemographic determinants was shown by higher risks for Black and Native Hawaiian and Other Pacific Islander mothers compared with White mothers, mothers with low educational attainment, and older mothers. Among modifiable risk factors, delayed/absent prenatal care, diabetes, hypertension, and maternal smoking were associated with increased risk, though they accounted for only 3-6% of stillbirths each. Two factors accounted for the largest proportion of late stillbirths: high maternal body mass index (BMI; 15%) and infants who were small for gestational age (38%). Participation in the supplemental nutrition for women, infants and children program was associated with a 28% reduction in overall stillbirth burden.

CONCLUSIONS

This study provides population-based evidence for stillbirth risk in the US. A high proportion of late stillbirths was associated with high maternal BMI and small for gestational age, whereas participation in supplemental nutrition programs was associated with a large reduction in stillbirth burden. Addressing obesity and fetal growth restriction, as well as broadening participation in nutritional supplementation programs could reduce late stillbirths.

Acute resveratrol exposure does not impact hemodynamics of the fetal sheep

Babies born growth restricted are at an increased risk of both poor short-and long-term outcomes. Current interventions to improve fetal growth are ineffective and do not lower the lifetime risk of poor health status. Maternal resveratrol (RSV) treatment increases uterine artery blood flow, fetal oxygenation, and fetal weight. However, studies suggest that diets high in polyphenols such as RSV may impair fetal hemodynamics. We aimed to characterize the effect of RSV on fetal hemodynamics to further assess its safety as an intervention strategy. Pregnant ewes underwent magnetic resonance imaging (MRI) scans to measure blood flow and oxygenation within the fetal circulation using phase contrast-MRI and T2 oximetry. Blood flow and oxygenation measures were performed in a basal state and then repeated while the fetus was exposed to RSV. Fetal blood pressure and heart rate were not different between states. RSV did not impact fetal oxygen delivery (DO2 ) or consumption (VO2 ). Blood flow and oxygen delivery throughout the major vessels of the fetal circulation were not different between basal and RSV states. As such, acute exposure of the fetus to RSV does not directly impact fetal hemodynamics. This strengthens the rationale for the use of RSV as an intervention strategy against fetal growth restriction.

Copy number variants and fetal growth in stillbirths

BACKGROUND

Fetal growth abnormalities are associated with a higher incidence of stillbirth, with small and large for gestational age infants incurring a 3 to 4- and 2 to 3-fold increased risk, respectively. Although clinical risk factors such as diabetes, hypertension, and placental insufficiency have been associated with fetal growth aberrations and stillbirth, the role of underlying genetic etiologies remains uncertain.

OBJECTIVE

This study aimed to assess the relationship between abnormal copy number variants and fetal growth abnormalities in stillbirths using chromosomal microarray.

STUDY DESIGN

A secondary analysis utilizing a cohort study design of stillbirths from the Stillbirth Collaborative Research Network was performed. Exposure was defined as abnormal copy number variants including aneuploidies, pathogenic copy number variants, and variants of unknown clinical significance. The outcomes were small for gestational age and large for gestational age stillbirths, defined as a birthweight <10th percentile and greater than the 90th percentile for gestational age, respectively.

RESULTS

Among 393 stillbirths with chromosomal microarray and birthweight data, 16% had abnormal copy number variants. The small for gestational age outcome was more common among those with abnormal copy number variants than those with a normal microarray (29.5% vs 16.5%; P=.038). This finding was consistent after adjusting for clinically important variables. In the final model, only abnormal copy number variants and maternal age remained significantly associated with small for gestational age stillbirths, with an adjusted odds ratio of 2.22 (95% confidence interval, 1.12-4.18). Although large for gestational age stillbirths were more likely to have an abnormal microarray: 6.2% vs 3.3% (P=.275), with an odds ratio of 2.35 (95% confidence interval, 0.70-7.90), this finding did not reach statistical significance.

CONCLUSION

Genetic abnormalities are more common in the setting of small for gestational age stillborn fetuses. Abnormal copy number variants not detectable by traditional karyotype make up approximately 50% of the genetic abnormalities in this population.

Risk of Stillbirth in Pregnancies Complicated by Diabetes, Stratified by Fetal Growth

OBJECTIVE

To compare stillbirth rates per week of expectant management stratified by birth weight in pregnancies complicated by gestational diabetes mellitus (GDM) or pregestational diabetes mellitus.

METHODS

A national population-based retrospective cohort study of singleton, nonanomalous pregnancies complicated by pregestational diabetes or GDM was performed using national birth and death certificate data from 2014 to 2017. Stillbirth rates per 10,000 patients (stillbirth incidence at gestational age week/ongoing pregnancies-[0.5×live births at gestational age week]) were determined for each week of pregnancy from 34 to 39 completed weeks of gestation. Pregnancies were stratified by birth weight, categorized as having small-for-gestational-age (SGA), appropriate-for-gestational-age (AGA), or large-for-gestational-age (LGA) fetuses, assigned by sex-based Fenton criteria. Relative risk (RR) and 95% CI for stillbirth were calculated for each gestational age week compared with the GDM-related AGA group.

RESULTS

We included 834,631 pregnancies complicated by either GDM (86.9%) or pregestational diabetes (13.1%) in the analysis, with a total of 3,033 stillbirths. Stillbirth rates increased with advancing gestational age for pregnancies complicated by both GDM and pregestational diabetes regardless of birth weight. Compared with pregnancies with AGA fetuses, those with both SGA and LGA fetuses were significantly associated with an increased risk of stillbirth at all gestational ages. Ongoing pregnancies at 37 weeks of gestation complicated by pregestational diabetes with LGA or SGA fetuses had respective stillbirth rates of 64.9 and 40.1 per 10,000 patients. Pregnancies complicated by pregestational diabetes had an RR of stillbirth of 21.8 (95% CI 17.4-27.2) for LGA fetuses and 13.5 (95% CI 8.5-21.2) for SGA fetuses compared with GDM-related AGA at 37 weeks of gestation. The greatest absolute risk of stillbirth was in pregnancies complicated by pregestational diabetes at 39 weeks of gestation with LGA fetuses (97/10,000).

CONCLUSION

Pregnancies complicated by both GDM and pregestational diabetes affected by pathologic fetal growth have an increased risk of stillbirth with advancing gestational age. This risk is significantly higher with pregestational diabetes, especially pregestational diabetes with LGA fetuses.

Placental pathology is necessary to understand common pregnancy complications and achieve an improved taxonomy of obstetrical disease

The importance of a fully functioning placenta for a good pregnancy outcome is unquestioned. Loss of function can lead to pregnancy complications and is often detected by a thorough placental pathologic examination. Placental pathology has advanced the science and practice of obstetrics and neonatal-perinatal medicine by classifying diseases according to underlying biology and specific patterns of injury. Many past obstacles have limited the incorporation of placental findings into both clinical studies and day-to-day practice. Limitations have included variability in the nomenclature used to describe placental lesions, a shortage of perinatal pathologists fully competent to analyze placental specimens, and a troubling lack of understanding of placental diagnoses by clinicians. However, the potential use of placental pathology for phenotypic classification, improved understanding of the biology of adverse pregnancy outcomes, the development of treatment and prevention, and patient counseling has never been greater. This review, written partly in response to a recent critique published in a major obstetrics-gynecology journal, reexamines the role of placental pathology by reviewing current concepts of biology; explaining the most recent terminology; emphasizing the usefulness of specific diagnoses for obstetrician-gynecologists, neonatologists, and patients; previewing upcoming changes in recommendations for placental submission; and suggesting future improvements. These improvements should include further consideration of overall healthcare costs, cost-effectiveness, the clinical value added of placental assessment, improvements in placental pathology education and practice, and leveraging of placental pathology to identify new biomarkers of disease and evaluate novel therapies tailored to specific clinicopathologic phenotypes of both women and infants.

Subsequent risk of stillbirth, preterm birth, and small for gestational age: A cross-outcome analysis of adverse birth outcomes

BACKGROUND

Stillbirth, preterm birth, and small for gestational age (SGA) birth have an increased recurrence risk. The occurrence of one of these biologically related outcomes could also increase the risk for another one of these outcomes in a subsequent pregnancy.

OBJECTIVES

We assessed cross-outcome risks for subsequent stillbirth, preterm birth, and SGA.

METHODS

We used live birth and fetal death records to identify singleton, sequential birth pairs in California (1997-2017). Stillbirth was defined as delivery at ≥20 weeks of gestation of a foetus that died in utero; preterm birth as live birth at 20-36 weeks; and small for gestational age as sex-specific birthweight <10th percentile for gestational age. Risk ratios (RR) were computed using modified Poisson regression and adjusted for potential confounders. Sensitivity analyses included analysing a cohort restricted to primiparous index births and using inverse-probability censoring weights.

RESULTS

Of 3,108,532 birth pairs, 16,668 (0.5%), 260,596 (8.4%) and 331,109 (10.7%) of index births were stillborn, preterm and SGA, respectively. Among individuals with an index stillbirth, the adjusted RRs were 1.90 (95% confidence interval [CI] 1.83, 1.98) for subsequent preterm and 1.35 (95% CI 1.28, 1.41) for subsequent SGA. Among those with index preterm birth, the adjusted RRs were 2.02 (95% CI 1.92, 2.13) for stillbirth and 1.42 (95% CI 1.41, 1.44) for SGA. Among those with index SGA, the adjusted RRs were 1.54 (95% CI 1.46, 1.63) for stillbirth and 1.45 (95% CI 1.44, 1.47) for preterm birth. Similar results were reported for sensitivity analyses.

CONCLUSIONS

Individuals experiencing stillbirth, preterm birth, or SGA in one pregnancy had an increased risk of one of these biologically related outcomes in a subsequent pregnancy. These findings could encourage enhanced surveillance for individuals who experience stillbirth, preterm birth, or SGA and desire a subsequent pregnancy.

Higher Dietary Intake of Animal Protein Foods in Pregnancy Is Associated with Lower Risk of Adverse Birth Outcomes

BACKGROUND

The prevalence of adverse birth outcomes is highest in resource-limited settings such as sub-Saharan Africa. Maternal consumption of diets with adequate nutrients during pregnancy may protect against these adverse outcomes.

OBJECTIVES

The objective was to determine the association between maternal dietary consumption of animal source foods (ASFs) and the risk of adverse birth outcomes among HIV-negative pregnant women in Tanzania.

METHODS

Using dietary intake data from 7564 HIV-negative pregnant women, we used Poisson regression with the empirical variance (generalized estimating equation) to estimate the RR of adverse birth outcomes-preterm birth, very preterm birth, small for gestational age (SGA), low birth weight (LBW), stillbirth, and neonatal death-for higher and lower frequency of ASF intake.

RESULTS

Median daily dietary intake of animal protein was 17 g (IQR: 1-48 g). Higher frequency of ASF protein intake was associated with lower risk of neonatal death (quartile 4 compared with quartile 1; RR: 0.59; 95% CI: 0.38, 0.90; P-trend = 0.01). Higher fish intake was associated with lower risk of very preterm birth (high tertile compared with low; RR: 0.76; 95% CI: 0.58, 0.99; P-trend = 0.02). Any meat intake was protective of preterm birth (RR: 0.73; 95% CI: 0.65, 0.82; P < 0.001), very preterm birth (P < 0.001), LBW (P < 0.001), and neonatal death (P = 0.01) but was associated with increased risk of SGA (RR:1.19; 95% CI: 1.01, 1.36; P = 0.04). Any egg intake was protective of very preterm birth (RR: 0.50; 95% CI: 0.31, 0.83; P = 0.01) as compared with no egg intake. Finally, any dairy intake was associated with lower risk of preterm birth (RR: 0.82; 95% CI: 0.68, 0.98; P = 0.03) and very preterm birth (RR: 0.53; 95% CI: 0.34, 0.84; P = 0.01).

CONCLUSIONS

Higher frequency of dietary intake of ASF is associated with lower risk of adverse birth outcomes in urban Tanzania. Promoting prenatal dietary intake of ASF may improve birth outcomes in this region and similar resource-limited settings.

A United States national reference for foetal growth for Asian American ethnicities

The purpose of this study was to calculate 10th, 50th, and 90th percentiles of birth weight for gestational age for the total US population and the Asian-American ethnicities. Using the US Natality data files for the years 1992-2020, estimated growth curves were determined across gestational ages and for each Asian American ethnic group-Chinese, Asian Indians, Japanese, Koreans, Filipino, and Vietnamese. Average weight at the 10th, 50th and 90th foetal growth percentiles by race/ethnicity and sex were calculated. Overall, for the 10th, 50th and 90th percentiles, Asian American average birth weight was 18, 90 and 144 g lower than the national average, respectively. We also found that Asian Indians consistently had the lowest birthweight, while Koreans had the highest birthweight among Asian Americans. Updated racial/ethnic-specific weight percentiles by gestational age can be a useful reference for accurate small and large-for-gestational age classifications among different Asian American sub-populations.Impact statementWhat is already known on this subject? Foetal growth is an important determinant of infants' immediate and long-term health outcomes and foetal growth reference curves have been developed to provide average birth weights for each week of gestation and identify growth-restricted as well as excess-weighing foetuses.What the results of this study add? Using the U.S. Natality data files for the years 1992-2020, estimated growth curves were determined across gestational ages and for each Asian American ethnic group-Chinese, Asian Indians, Japanese, Koreans, Filipino, and Vietnamese. Average weight at the 10th, 50th and 90th foetal growth percentiles by race/ethnicity and sex were calculated.What the implications are of these findings for clinical practice and/or further research? Updated racial/ethnic-specific weight percentiles by gestational age can be a useful reference for accurate small and large-for-gestational age classifications among different Asian American sub-groups.

The effects of post-frozen-thawed embryo transfer pregnancy on early fetal development

AIM

Frozen-thawed embryo transfer (FET) has gained popularity as an assistive reproductive technology despite its increased risk of large-for-gestational-age offspring. This study aimed to analyze the effect of FET on fetal development, particularly the growth rate and estimated fetal weight (EFW) throughout pregnancy.

METHODS

This was a single-center, retrospective study that examined 97 patients with FET conception and 477 patients with natural conception (NC) who underwent labor and delivery at our clinic between December 2015 and June 2019. Crown-rump length (CRL) in the first trimester and EFW measurements in the second and third trimesters were obtained from transabdominal ultrasound records. Birthweight was adjusted for sex, parity, and gestational age. Regression coefficients of CRL, EFW, and birthweight were compared between the FET and NC groups to examine the growth rate. Multiple regression analysis was performed to determine the relationship between birth size and baseline characteristics.

RESULTS

The growth rate was higher in the first trimester in the FET group than in the NC group (difference: 0.19 mm/day, p = 0.018). CRL, EFW, and adjusted birthweight were higher in the FET group than in the NC group throughout pregnancy. The factors associated with the development of larger offspring through FET than through NC were advanced maternal age, primiparity, cesarean section delivery, and high birthweight.

CONCLUSIONS

Throughout pregnancy, FET resulted in a larger offspring than in NC, with accelerated growth observed only during the first trimester. Thus, FET highly affects early fetal development.

Geographical variations in maternal dietary patterns during pregnancy associated with birth weight in Shaanxi province, Northwestern China

The geographical variation of maternal dietary patterns related to birth outcomes is important for improving the health of mothers and children; however, it is currently unknown. Thus, the objective of the study was to investigate geographical variations of maternal dietary pattern during pregnancy, and evaluate the spatial varying association of maternal dietary patterns in pregnancy with abnormal birth weight. A population-based cross-sectional study was conducted in Shaanxi province in Northwest China in 2013 to evaluate the relationship between abnormal birth weight and dietary pattern using the Geographically Weighted Logistic Regression (GWLR). Three dietary patterns during pregnancy were extracted through factor analysis, explaining approximately 45.8% of the variability of food intake. Approximately 81.6% of mothers with higher scores on the equilibrium pattern was more unlikely to have small for gestational age (SGA) infants, with the lower OR observed in Central and South Shaanxi. The snacks pattern was positively associated with low birth weight (LBW) for 23.2% of participants, with the highest OR in Central Shaanxi. Among about 80.0% of participants with higher scores on the snacks pattern living in South and Central Shaanxi, there was a higher risk for SGA. The OR values tend to descend from South to North Shaanxi. The OR values of the negative association between prudent pattern and LBW decreased from South to North Shaanxi among approximately 59.3% of participants. The prudent pattern was also negatively associated with the increasing risk of fetal macrosomia among 19.2% of participants living mainly in South Shaanxi. The association of maternal dietary patterns during pregnancy with abnormal birth weight varied geographically across Shaanxi province. The findings emphasize the importance of geographical distribution to improve the dietary patterns among disadvantaged pregnant women.

Reduced fetal growth velocity precedes antepartum fetal death

OBJECTIVES

To determine whether decreased fetal growth velocity precedes antepartum fetal death and to evaluate whether fetal growth velocity is a better predictor of antepartum fetal death compared to a single fetal biometric measurement at the last available ultrasound scan prior to diagnosis of demise.

METHODS

This was a retrospective, longitudinal study of 4285 singleton pregnancies in African-American women who underwent at least two fetal ultrasound examinations between 14 and 32 weeks of gestation and delivered a liveborn neonate (controls; n = 4262) or experienced antepartum fetal death (cases; n = 23). Fetal death was defined as death diagnosed at ≥ 20 weeks of gestation and confirmed by ultrasound examination. Exclusion criteria included congenital anomaly, birth at < 20 weeks of gestation, multiple gestation and intrapartum fetal death. The ultrasound examination performed at the time of fetal demise was not included in the analysis. Percentiles for estimated fetal weight (EFW) and individual biometric parameters were determined according to the Hadlock and Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (PRB/NICHD) fetal growth standards. Fetal growth velocity was defined as the slope of the regression line of the measurement percentiles as a function of gestational age based on two or more measurements in each pregnancy.

RESULTS

Cases had significantly lower growth velocities of EFW (P < 0.001) and of fetal head circumference, biparietal diameter, abdominal circumference and femur length (all P < 0.05) compared to controls, according to the PRB/NICHD and Hadlock growth standards. Fetuses with EFW growth velocity < 10^th percentile of the controls had a 9.4-fold and an 11.2-fold increased risk of antepartum death, based on the Hadlock and customized PRB/NICHD standards, respectively. At a 10% false-positive rate, the sensitivity of EFW growth velocity for predicting antepartum fetal death was 56.5%, compared to 26.1% for a single EFW percentile evaluation at the last available ultrasound examination, according to the customized PRB/NICHD standard.

CONCLUSIONS

Given that 74% of antepartum fetal death cases were not diagnosed as small-for-gestational age (EFW < 10^th percentile) at the last ultrasound examination when the fetuses were alive, alternative approaches are needed to improve detection of fetuses at risk of fetal death. Longitudinal sonographic evaluation to determine growth velocity doubles the sensitivity for prediction of antepartum fetal death compared to a single EFW measurement at the last available ultrasound examination, yet the performance is still suboptimal. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Consensus Definition of Fetal Growth Restriction in Intrauterine Fetal Death: A Delphi Procedure

CONTEXT.—

Fetal growth restriction is a risk factor for intrauterine fetal death. Currently, definitions of fetal growth restriction in stillborns are heterogeneous.

OBJECTIVES.—

To develop a consensus definition for fetal growth restriction retrospectively diagnosed at fetal autopsy in intrauterine fetal death.

DESIGN.—

A modified online Delphi survey in an international panel of experts in perinatal pathology, with feedback at group level and exclusion of nonresponders. The survey scoped all possible variables with an open question. Variables suggested by 2 or more experts were scored on a 5-point Likert scale. In subsequent rounds, inclusion of variables and thresholds were determined with a 70% level of agreement. In the final rounds, participants selected the consensus algorithm.

RESULTS.—

Fifty-two experts participated in the first round; 88% (46 of 52) completed all rounds. The consensus definition included antenatal clinical diagnosis of fetal growth restriction OR a birth weight lower than third percentile OR at least 5 of 10 contributory variables (risk factors in the clinical antenatal history: birth weight lower than 10th percentile, body weight at time of autopsy lower than 10th percentile, brain weight lower than 10th percentile, foot length lower than 10th percentile, liver weight lower than 10th percentile, placental weight lower than 10th percentile, brain weight to liver weight ratio higher than 4, placental weight to birth weight ratio higher than 90th percentile, histologic or gross features of placental insufficiency/malperfusion). There was no consensus on some aspects, including how to correct for interval between fetal death and delivery.

CONCLUSIONS.—

A consensus-based definition of fetal growth restriction in fetal death was determined with utility to improve management and outcomes of subsequent pregnancies.

Pregnancy after Bariatric Surgery: A Nested Case-Control Study of Risk Factors for Small for Gestational Age Babies in AURORA

Bariatric surgery prior to pregnancy is a significant risk factor for small for gestational age (SGA) babies. This case-control study investigated differences between mothers delivering an SGA baby following bariatric surgery, compared to those delivering an appropriate for gestational age (AGA) baby. Out of 129 babies born to mothers in the AURORA cohort study, 25 were SGA (<10th percentile) and 97 were AGA (10th-90th percentile). Higher gestational weight gain (GWG) was significantly associated with decreased odds of SGA (aOR per kg 0.92, 95% CI 0.85-0.99). According to the Institute of Medicine GWG guidelines, 44% of SGA mothers had 'inadequate' GWG compared to 17% of AGA mothers. Nearly half of the mothers had 'excessive' GWG yet still gave birth to an SGA or AGA baby. Mothers of SGA babies lost more weight following bariatric surgery (45.6 ± 14.4 kg vs. 39.0 ± 17.9 kg). Women who reported receiving nutritional advice following bariatric surgery were significantly less likely to have an SGA baby (aOR 0.15, 95% CI 0.0.4-0.55). Women with a history of bariatric surgery should be provided with specialized support before and during pregnancy to encourage adequate nutritional intake and weight gain to support healthy fetal growth.

Application mattampu as fetal growth education media during pregnancy based on android

OBJECTIVE

The objective of the study was to determine the increase in knowledge of pregnant women about fetal growth during pregnancy by using an android application that is given the name Mattampu.

METHOD

The study consists of 90 pregnant women; 30 first trimester, 30 second trimester pregnant women, and 30 third trimester pregnant women. The sampling technique uses accidental sampling. Pregnant women are given a questionnaire about fetal growth as a pretest, then are trained using an Android-based learning application about fetal growth. After that, they were asked to read and given a post-test questionnaire. McNemar statistical test is used to assess the knowledge of pregnant women.

RESULTS

All pregnant women in all trimesters given learning through the android application media significantly increased their knowledge of fetal growth.

CONCLUSION

The use of the application could increase the knowledge of pregnant women about fetal growth.

African American Unemployment and the Disparity in Periviable Births

Periviable infants (i.e., born before 26 complete weeks of gestation) represent fewer than .5% of births in the US but account for 40% of infant mortality and 20% of billed hospital obstetric costs. African American women contribute about 14% of live births in the US, but these include nearly a third of the country’s periviable births. Consistent with theory and with periviable births among other race/ethnicity groups, males predominate among African American periviable births in stressed populations. We test the hypothesis that the disparity in periviable male births among African American and non-Hispanic white populations responds to the African American unemployment rate because that indicator not only traces, but also contributes to, the prevalence of stress in the population. We use time-series methods that control for autocorrelation including secular trends, seasonality, and the tendency to remain elevated or depressed after high or low values. The racial disparity in male periviable birth increases by 4.45% for each percentage point increase in the unemployment rate of African Americans above its expected value. We infer that unemployment—a population stressor over which our institutions exercise considerable control—affects the disparity between African American and non-Hispanic white periviable births in the US.

Fetal Growth Acceleration-Current Approach to the Big Baby Issue

Background and Objectives: Fetal overgrowth is related to many perinatal complications, including stillbirth, cesarean section, maternal and neonatal injuries, and shoulder dystocia. It is related to maternal diabetes, obesity, and gestational weight gain but also happens in low-risk pregnancies. There is ongoing discussion regarding definitions, methods of detection, and classification. The method used for detection is crucial as it draws a line between those at risk and low-risk popula-tions. Materials and Methods: For this narrative review, relevant evidence was identified through PubMed search with one of the general terms (macrosomia, large-for-gestational-age) combined with the outcome of interest. Results: This review summarizes evidence on the relation of fetal overgrowth with stillbirth, cesarean sections, shoulder dystocia, anal sphincter injury, and hem-orrhage. Customized growth charts help to detect mothers and fetuses at risk of those complica-tions. Relations between fetal overgrowth and diabetes, maternal weight, and gestational weight gain were investigated. Conclusions: a substantial proportion of complications are an effect of the fetus growing above its potential and should be recognized as a new dangerous condition of Fetal Growth Acceleration.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Large-for-gestational-age or macrosomia as a classifier for risk of adverse perinatal outcome: a retrospective cross-sectional study

OBJECTIVE

Small for gestational age (SGA) fetuses and neonates are of great interest, while those who are too big are much less studied. The aim was to analyze the classifiers described by ACOG "Fetal macrosomia" practice bulletin as predictors of adverse perinatal outcomes for overgrown fetuses and their mothers.

MATERIALS

From a database of 53,586 singleton term births, appropriate-for-gestational-age (AGA), large for gestational age (LGA), and macrosomic deliveries were selected. AGA served as a control. The crude and adjusted odds ratios (aORs) were calculated for large-for-gestational-age >90th centile, and macrosomia >4000 g, >4250 g, and >4500 g. Patients with and without diabetes were analyzed separately.

RESULTS

Macrosomia >4000 g performed poorer than other classifiers. LGA performed comparably to other definitions of macrosomia. Diabetes carries a severe risk of complications for overgrown neonates, but those non-diabetic also have increased risk.

CONCLUSIONS

Definition of macrosomia as weight >4000 g should be reconsidered. LGA >90th centile should be used as a definition of fetal overgrowth along with other definitions of macrosomia.

Characteristics of Stillbirths Associated With Diabetes in a Diverse U.S. Cohort

OBJECTIVE

To characterize stillbirths associated with pregestational diabetes and gestational diabetes mellitus (GDM) in a large, prospective, U.S. case-control study.

METHODS

A secondary analysis of stillbirths among patients enrolled in a prospective; multisite; geographically, racially, and ethnically diverse case-control study in the United States was performed. Singleton gestations with complete information regarding diabetes status and with a complete postmortem evaluation were included. A standard evaluation protocol for stillbirth cases included postmortem evaluation, placental pathology, clinical testing as performed at the discretion of the health care professional, and a recommended panel of tests. A potential cause of death was assigned to stillbirth cases using a standardized classification tool. Demographic and delivery characteristics among women with pregestational diabetes and GDM were compared with characteristics of women with no diabetes in pairwise comparisons using χ or two-sample t tests as appropriate. Sensitivity analysis was performed excluding pregnancies with genetic conditions or major fetal malformations.

RESULTS

Of 455 stillbirth cases included in the primary analysis, women with stillbirth and diabetes were more likely to be older than 35 years and have a higher body mass index. They were also more likely to have a gestational hypertensive disorder than women without diabetes (28% vs 9.1%; P<.001). Women with pregestational diabetes had more large-for-gestational-age (LGA) neonates (26% vs 3.4%; P<.001). Stillbirths occurred more often at term in women with pregestational diabetes (36%) and those with GDM (52%). Maternal medical complications, including pregestational diabetes and others, were more often identified as a probable or possible cause of death among stillbirths with maternal diabetes (43% vs 4%, P<.001) as compared with stillbirths without diabetes.

CONCLUSION

Compared with stillbirths in women with no diabetes, stillbirths among women with pregestational diabetes and GDM occur later in pregnancy and are associated with hypertensive disorders of pregnancy, maternal medical complications, and LGA.

Stillbirth maternity care measurement and associated factors in population-based surveys: EN-INDEPTH study

BACKGROUND

Household surveys remain important sources of maternal and child health data, but until now, standard surveys such as Demographic and Health Surveys (DHS) have not collected information on maternity care for women who have experienced a stillbirth. Thus, nationally representative data are lacking to inform programmes to address the millions of stillbirths which occur annually.

METHODS

The EN-INDEPTH population-based survey of women of reproductive age was undertaken in five Health and Demographic Surveillance System sites in Bangladesh, Ethiopia, Ghana, Guinea-Bissau and Uganda (2017-2018). All women answered a full birth history with additional questions on pregnancy losses (FBH+) or full pregnancy history (FPH). A sub-sample, including all women reporting a recent stillbirth or neonatal death, was asked additional maternity care questions. These were evaluated using descriptive measures. Associations between stillbirth and maternal socio-demographic characteristics, babies' characteristics and maternity care use were assessed using a weighted logistic regression model for women in the FBH+ group.

RESULTS

A total of 15,591 women reporting a birth since 1 January 2012 answered maternity care questions. Completeness was very high (> 99%), with similar proportions of responses for both live and stillbirths. Amongst the 14,991 births in the FBH+ group, poorer wealth status, higher parity, large perceived baby size-at-birth, preterm or post-term birth, birth in a government hospital compared to other locations and vaginal birth were associated with increased risk of stillbirth after adjusting for potential confounding factors. Regarding association with reported postnatal care, women with a stillbirth were more likely to report hospital stays of > 1 day. However, women with a stillbirth were less likely to report having received a postnatal check compared to those with a live birth.

CONCLUSIONS

Women who had experienced stillbirth were able to respond to questions about pregnancy and birth, and we found no reason to omit questions to these women in household surveys. Our analysis identified several potentially modifiable factors associated with stillbirth, adding to the evidence-base for policy and action in low- and middle-income contexts. Including these questions in DHS-8 would lead to increased availability of population-level data to inform action to end preventable stillbirths.

No. 394-Stillbirth Investigation

OBJECTIVES

To provide an investigation protocol to help health care providers determine the cause of a fetal death.

OPTIONS

Consideration has been given to protocols for the investigation of fetal death that are currently available in Canada and in other countries.

OUTCOMES

Identification of possible causes of stillbirth and their relationship to future pregnancies.

EVIDENCE

Articles related to the etiology of fetal death were identified in a search of PubMed (June 2006 to September 2018), the Cochrane Library, and investigation protocols from the American College of Obstetricians and Gynecologists, the International Stillbirth Alliance Collaborative for Improving Classification of Perinatal Deaths, the Royal College of Obstetricians and Gynaecologists, the Queensland clinical guidelines, and the Reproductive Care Program of Nova Scotia.

BENEFITS

To provide better advice for women regarding possible causes of fetal death and implications for future pregnancies.

VALIDATION

The evidence obtained was reviewed and evaluated by the Maternal-Fetal Medicine Committee and the Clinical Practice Obstetrics Committee of the Society of Obstetricians and Gynaecologists of Canada. The level of evidence and quality of the recommendation made was described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care.

RECOMMENDATIONS

Macrosomic Newborns Delivered at Term after Labor among Nondiabetic Women: Maternal and Neonatal Morbidities

OBJECTIVE

This study aimed to compare morbidities among nonmacrosomic versus macrosomic singleton live births of nondiabetic women who labored.

STUDY DESIGN

This retrospective study utilized the 2003 revision of U.S. birth certificate data of singleton live births (2011-2013) at 37 to 41 weeks who labored. The primary outcomes were composite maternal and neonatal morbidities (CMM and CNM, respectively). We compared these outcomes by birth weight, 2,500 to 3,999 g (group 1; reference), 4,000 to 4,449 g (group 2), and 4,500 to 5,999 g (group 3). We used multivariable Poisson regression analyses to examine the association between birth weight groups and the outcomes.

RESULTS

Among 6,691,338 live births, 92.0% were in group 1, 7.1% in group 2, and 0.9% in group 3. The overall CMM and CNM rates were 4.4 and 6.8 per 1,000 live births, respectively. Compared with group 1, the risk of CMM was significantly higher in group 2 (adjusted risk ratio [aRR] = 1.50; 95% confidence interval [CI]: 1.44-1.56) and group 3 (aRR = 2.00; 95% CI: 1.82-2.19). Likewise, the risk of CNM was significantly higher in group 2 (aRR = 1.38; 95% CI: 1.33-1.43) and group 3 (aRR = 2.57; 95% CI: 2.40-2.75) than in group 1.

CONCLUSION

Nondiabetic women who labor with a macrosomic newborns have a significantly higher rate of adverse outcomes than nonmacrosomic.

Maternal Dietary Selenium Intake during Pregnancy Is Associated with Higher Birth Weight and Lower Risk of Small for Gestational Age Births in the Norwegian Mother, Father and Child Cohort Study

Selenium is an essential trace element involved in the body’s redox reactions. Low selenium intake during pregnancy has been associated with low birth weight and an increased risk of children being born small for gestational age (SGA). Based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we studied the association of maternal selenium intake from diet and supplements during the first half of pregnancy (n = 71,728 women) and selenium status in mid-pregnancy (n = 2628 women) with birth weight and SGA status, according to population-based, ultrasound-based and customized growth standards. An increase of one standard deviation of maternal dietary selenium intake was associated with increased birth weight z-scores (ß = 0.027, 95% CI: 0.007, 0.041) and lower SGA risk (OR = 0.91, 95% CI 0.86, 0.97) after adjusting for confounders. Maternal organic and inorganic selenium intake from supplements as well as whole blood selenium concentration were not associated with birth weight or SGA. Our results suggest that a maternal diet rich in selenium during pregnancy may be beneficial for foetal growth. However, the effect estimates were small and further studies are needed to elucidate the potential impact of selenium on foetal growth.

Perinatal death audit and classification of stillbirths in two provinces in Papua New Guinea: A retrospective analysis

OBJECTIVE

To undertake a retrospective perinatal death audit and assessment of avoidable factors associated with stillbirths among a cohort of women in two provinces in Papua New Guinea.

METHODS

We used data from an ongoing cluster-randomized crossover trial in 10 sites among 4600 women in Papua New Guinea (from 2017 to date). The overarching aim is to improve birth outcomes. All stillbirths from July 2017 to January 2020 were identified. The Perinatal Problem Identification Program was used to analyze each stillbirth and review associated avoidable factors.

RESULTS

There were 59 stillbirths among 2558 births (23 per 1000 births); 68% (40/59) were classified "fresh" and 32% as "macerated". Perinatal cause of death was identified for 63% (37/59): 30% (11/37) were due to intrapartum asphyxia and traumatic breech birth and 19% (7/37) were the result of pre-eclampsia. At least one avoidable factor was identified for 95% (56/59) of stillbirths. Patient-associated factors included lack of response to reduced fetal movements and delay in seeking care during labor. Health personnel-associated factors included poor intrapartum care, late diagnosis of breech presentation, and prolonged second stage with no intervention.

CONCLUSION

Factors associated with stillbirths in this setting could be avoided through a package of interventions at both the community and health-facility levels.

The PLANES study: a protocol for a randomised controlled feasibility study of the placental growth factor (PlGF) blood test-informed care versus standard care alone for women with a small for gestational age fetus at or after 32 + 0 weeks' gestation

Background

Stillbirth remains a major concern across the globe and in some high-resource countries, such as the UK; efforts to reduce the rate have achieved only modest reductions. One third of stillborn babies are small for gestational age (SGA), and these pregnancies are also at risk of neonatal adverse outcomes and lifelong health problems, especially when delivered preterm. Current UK clinical guidance advocates regular monitoring and early term delivery of the SGA fetus; however, the most appropriate regimen for surveillance of these babies remains unclear and often leads to increased intervention for a large number of these women. This pilot trial will determine the feasibility of a large-scale trial refining the risk of adverse pregnancy outcome in SGA pregnancies using biomarkers of placental function sFlt-1/PlGF, identifying and intervening in only those deemed at highest risk of stillbirth.

Methods

PLANES is a randomised controlled feasibility study of women with an SGA fetus that will be conducted at two tertiary care hospitals in the UK. Once identified on ultrasound, women will be randomised into two groups in a 3:1 ratio in favour of sFlt-1/PlGF ratio led management vs standard care. Women with an SGA fetus and a normal sFlt-1/PlGF ratio will have a repeat ultrasound and sFlt-1/PlGF ratio every 2 weeks with planned birth delayed until 40 weeks. In those women with an SGA fetus and an abnormal sFlt-1/PlGF ratio, we will offer birth from 37 weeks or sooner if there are other concerning features on ultrasound. Women assigned to standard care will have an sFlt-1/PlGF ratio taken, but the results will be concealed from the clinical team, and the woman’s pregnancy will be managed as per the local NHS hospital policy. This integrated mixed method study will also involve a health economic analysis and a perspective work package exploring trial feasibility through interviews and questionnaires with participants, their partners, and clinicians.

Discussion

Our aim is to determine feasibility through the assessment of our ability to recruit and retain participants to the study. Results from this pilot study will inform the design of a future large randomised controlled trial that will be adequately powered for adverse pregnancy outcome. Such a study would provide the evidence needed to guide future management of the SGA fetus.

Trial registration

ISRCTN58254381. Registered on 4 July 2019

Preventing term stillbirth: benefits and limitations of using fetal growth reference charts

PURPOSE OF REVIEW

This review examines the variation in clinical practice with regards to ultrasound estimation of fetal weight, as well as calculation of fetal weight centiles.

RECENT FINDINGS

Placental dysfunction is associated with fetal smallness from intrauterine malnutrition as well as fetal disability and even stillbirth from hypoxemia. Although estimating fetal weight can be done accurately, the issue of which fetal weight centile chart should be used continues to be a contentious topic. The arguments against local fetal growth charts based on national borders and customization for variables known to be associated with disease are substantial. As for other human diseases such as hypertension and diabetes, there is a rationale for the use of an international fetal growth reference standard. Irrespective of the choice of fetal growth reference standard, a significant limitation of small for gestational age (SGA) detection programs to prevent stillbirth is that the majority of stillborn infants at term were not SGA at the time of demise.

SUMMARY

Placental dysfunction can present with SGA from malnutrition and/or stillbirth from hypoxemia depending on the gestational age of onset. Emerging data show that at term, fetal Doppler arterial redistribution is associated more strongly with perinatal death than fetal size. Properly conducted trials of the role for maternal characteristics, fetal size, placental biomarkers, and Doppler assessing fetal well-being are required urgently.

Routine third-trimester ultrasound in low-risk pregnancies and perinatal death: a systematic review and meta-analysis

OBJECTIVE

This study aimed to determine whether routine third-trimester ultrasounds in low-risk pregnancies decrease the rate of perinatal death compared with regular antenatal care with serial fundal height measurements.

DATA SOURCES

This was a systematic review and meta-analysis of randomized control trials to identify relevant studies published from inception to October 2019. The databases used were Ovid, PubMed, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials using a combination of key words related to "third trimester ultrasound" and "low-risk."

STUDY ELIGIBILITY CRITERIA

We included all randomized control trials of singleton, nonanomalous low-risk pregnancies that were randomized to either one or more third-trimester ultrasounds (ultrasound group) or serial fundal height (fundal height group). Exclusion criteria were patients with multiple gestations, maternal medical complications, or fetal abnormalities requiring a third-trimester ultrasound.

STUDY APPRAISAL AND SYNTHESIS METHODS

The primary outcome was the rate of perinatal death. The secondary outcomes were rates of fetal growth restriction, suspected large for gestational age, polyhydramnios, oligohydramnios, fetal anomalies, antenatal interventions, stillbirth, neonatal death, cesarean delivery, induction of labor, and other neonatal outcomes. This meta-analysis was performed with the use of the random effects model of DerSimonian and Laird to produce relative risk or mean difference with a corresponding 95% confidence interval.

RESULTS

A total of 7 randomized control trials with 23,643 participants (12,343 in the ultrasound group vs 11,300 in the fundal height group) were included. The total rate of perinatal death was similar among the groups (41 of 11,322 [0.4%] vs 34 of 10,285 [0.3%]; relative risk, 1.14; 95% confidence interval, 0.68-1.89). The rate of fetal growth restriction was higher in the ultrasound group (763 of 10,388 [7%] vs 337 of 9021 [4%]; relative risk, 2.11; 95% confidence interval, 1.86-2.39) and the rate of suspected large for gestational age (1060 of 3513 [30%] vs 375 of 3558 [11%]; relative risk, 2.84; 95% confidence interval, 2.6-3.2). Polyhydramnios was also significantly higher in the ultrasound group than the fundal height group (18 of 323 [6%] vs 4 of 322 [1%] relative risk, 3.93; 95% confidence interval, 1.4-11). The rates of the remainder of the secondary outcomes were similar among the groups.

CONCLUSION

Routine third-trimester ultrasounds do not decrease the rate of perinatal death compared with serial fundal height in low-risk pregnancies. Ideally, an adequately powered trial is warranted to determine whether perinatal mortality in the fundal height group can be reduced by one-third with third-trimester ultrasound.

Risk factors for antepartum death in term pregnancies

OBJECTIVE

To identify risk factors for antepartum fetal death (APD) in term pregnancies while considering maternal, pregnancy and fetal characteristics.

MATERIALS AND METHODS

Our study took place between the years 1988-2013. A total of 272,527 singleton births at term were recorded during this time period, including 524 cases of APD (0.2%). Cases of known chromosomal or other fetal abnormalities and cases with poor prenatal care were excluded. In order to identify independent risk factors contributing to antepartum fetal death in term we conducted a multivariate analysis using logistic regression.

RESULTS

The main risk factors found to be significantly associated with APD in term were suspected intrauterine growth restriction (OR = 2.70, p < .001), diabetes (OR = 1.37, p = .05), hypertensive disorders (OR = 1.59, p = .01), advanced maternal age (OR = 1.03, p < .001) and grand-multiparity (OR = 1.79, p < .001). Advanced gestational age was not significantly associated with APD (38.95 vs. 39.44, p < .001).

CONCLUSIONS

Most of the risk factors for antepartum fetal death in term pregnancies found in this study coincide with known risk factors for APD as described in previous studies. We believe that in the presence of these risk factors, closer surveillance and careful medical management of the pregnancy are required, in order to reduce the incidence of APD, including induction of labor at advanced gestational age.

A comparison of placental pathology between small for gestational age infants at < 5 % versus 5-9

INTRODUCTION

Among SGA newborns, those < 5th % for GA are more likely to have adverse outcomes than those at 5-9th %. The differential morbidity and mortality may be due to abnormal placental pathology between groups. Our purpose was to compare placental pathology characteristics and composite placental pathology among SGA infants with birth weights <5th % vs. 5-9th %.

METHODS

This study is a secondary analysis of a multicenter, retrospective cohort study. Placental pathological variables and composite placental pathology (CPP) among SGA infants <5th % and 5-9th % were compared. Multivariable logistic regression was used to model the probability of an infant's birth weight being classified as <5th % based on pathology characteristics.

RESULTS

Of 11,487 live singleton births, 925 SGA infants met inclusion criteria. Placental pathology was available for review in 407 (44 %) SGA infants: 210 (51.6 %) <5th % and 197 (48.4 %) 5-9th %. A decreased placental weight for GA, was more common in the <5th % group compared to the 5-9th % group (p = 0.0019). No significant differences in the distribution of pathological variables or in CPP (p = 0.3) was observed between the two centile groups. A decreased placental weight was the only reliable predictor of an infant's birth weight centile group (p = 0.0018).

CONCLUSIONS

Placental hypoplasia, reflected by a decreased placental weight for GA, was significantly more common among SGA infants < 5th % compared to the 5-9th %. There was no difference in placental pathological features or CPP between the two centile groups of SGA infants.

Phenotypes of fetal macrosomia and risk of stillbirth among term deliveries over the previous four decades

OBJECTIVES

To evaluate the association between macrosomia and stillbirth over the previous four decades and to determine the consistency of the relationship.

METHODS

This was a population-based retrospective cohort study using United States Natality and Fetal Death Data from 1982 to 2017 and restricted to the gestational age range of 37-41 weeks inclusive. Macrosomia was defined as birthweight ≥4000 g and subdivided into its grades as previously recommended: grade 1 (4000-4499 g), grade 2 (4500-4999 g), and grade 3 (≥5000 g). We calculated temporal trends of stillbirth among fetuses with macrosomia over the years using joinpoint regression. We generated odds ratios from adjusted binomial logistic regression models to examine the association between macrosomia and risk of stillbirth stratified by grades using normal-weight infants (2500-3999 g) as referent.

RESULTS

Within the fetal macrosomia group, the rate of stillbirth declined from 2.04/1000 in 1982 to 1.05/1000 by the end of the study period (2017), representing a drop of about 48.5%. For the normal-weight fetuses, stillbirth rate declined from 1.95/1000 to 0.83/1000, equivalent to a decline of 57.4%. Macrosomia was significantly associated with elevated risk for stillbirth: grade 2 (OR = 1.27; 95% CI = 1.22-1.32) and grade 3 (OR = 5.97; 95% CI = 5.69-6.22).

CONCLUSIONS

Fetal macrosomia is a significant risk factor for fetal demise with the worst intrauterine survival observed among those classified as grade 3. Fetal macrosomia is a heterogeneous rather than a homogeneous entity in terms of risk profiles, and this needs to be considered in future policy guidelines.

Identification of newborns with birthweight ≥ 4,500g: Ultrasound within one- vs. two weeks of delivery

OBJECTIVE

Our objective was to compare the diagnostic characteristics of sonographic estimated fetal weight (SEFW) done within 7 versus 8-14 days before delivery for detection of fetal macrosomia (birthweight ≥ 4500 g).

STUDY DESIGN

We performed a multicenter, retrospective cohort study of all non-anomalous singletons with SEFW ≥ 4000 g by Registered Diagnostic Medical Sonographers conducted within 14 days of delivery. Cohorts were grouped by time interval between ultrasound and delivery: 0-7 days versus 8-14 days. The detection rate (DR) and false positive rate (FPR) for detection of birthweight (BW) ≥ 4500 g were compared between groups with subgroup analysis for diabetic women. Area under the receiver operator curve (AUC) was calculated to analyze all possible SEFW cutoffs within our cohort.

RESULTS

A total of 330 patients met inclusion criteria with 250 (75.8 %) having SEFW within 7 days and 80 (24.2 %) with SEFW 8-14 days prior to delivery. The rate of macrosomia was 15.1 % (N = 51). The DR for macrosomia was significantly higher when SEFW was performed within 7 days of delivery compared to 8-14 days among non-diabetic (73.0 % vs 7.1 %; p < 0.001) and diabetic women (76.5 % vs 16.7 %; p = 0.02). There was no significant change in FPR in either group. The AUC for detection of macrosomia was significantly higher when SEFW was performed within 7 days versus 8-14 days (0.89 vs 0.63; p < 0.01).

CONCLUSION

With SEFW ≥ 4000 g, the detection of BW ≥ 4500 g is significantly higher when the sonographic examination is within 7 days of birth irrespective of maternal diabetes.

Association between false positive glucose challenge test results and large-for-gestational-age infants: a retrospective cohort study

OBJECTIVES

There is no consensus regarding a possible relation between false positive glucose challenge test (GCT) results and large-for-gestational-age (LGA) infants. This study aimed to clarify the association between false positive GCT results and LGA, after adjusting for potential confounding factors, using a large clinical dataset.

DESIGN

Retrospective cohort study.

SETTING

National Hospital Organisation Kofu National Hospital, which is a community hospital, between January 2012 and August 2019.

PARTICIPANTS

Japanese women who underwent GCT between 24 and 28 weeks of gestation at the hospital were included. After excluding those with gestational diabetes mellitus, diabetes in pregnancy and multiple pregnancies, subjects were divided into a false positive GCT group (≥140 mg/dL) and a GCT negative group (<140 mg/dL).

METHODS

Obstetric records of patients were examined. The χ²-test and multivariable logistic regression analysis were used to investigate the association between false positive GCT results and LGA.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incidence of LGA and the association between false positive GCT results and LGA.

RESULTS

The mean subject age was 31.4±5.5 years, with 43.3% nulliparity (n=974) and 2160 (96.1%) term deliveries. The incidence of LGA was 9.4% (211/2248) and 11.4% (257/2248) of the women had false positive GCT results. False positive GCT results were significantly associated with an increased risk of LGA (OR, 1.51; 95% CI, 1.02 to 2.23), after controlling for maternal age, prepregnancy maternal weight, maternal weight gain during pregnancy and parity.

CONCLUSIONS

It appears that there is a significant association between false positive GCT results and LGA. Additional research is required to confirm these results and to investigate appropriate interventions for women with abnormal screens for gestational diabetes mellitus.

Keep it in the family: comparing perinatal risks in small-for-gestational-age infants based on population vs within-sibling designs

BACKGROUND

Small-for-gestational-age (SGA) birth is commonly used as a proxy for fetal growth restriction, but also includes constitutionally small infants. Genetic factors account for almost half of the risk of SGA birth. We estimated perinatal risks of SGA birth using both population-based and within-sibling analyses, where the latter by design controls for shared genetic factors and maternal environmental factors that are constant across pregnancies.

METHODS

This was a prospective nationwide cohort study of 2 616 974 singleton infants born in Sweden between January 1987 and December 2012, of whom 1 885 924 were full siblings. We estimated associations between severe or moderate SGA (<3rd percentile and 3rd to <10th percentiles, respectively) and risks of stillbirth, neonatal mortality and morbidity, using both population-based and within-sibling analyses. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated in stillbirth analyses, whereas relative risks (RRs) were used for analyses of neonatal outcomes.

RESULTS

Compared with non-SGA births (>10th percentile), the HR (95% CI) of stillbirth was 18.5 (95% CI 17.4-19.5) among severe SGA births in the population analysis and 22.5 (95% CI 18.7-27.1) in the within-sibling analysis. In non-malformed infants, RRs for neonatal mortality in moderate and severe SGA infants were similarly increased in both population and within-sibling analyses. In term non-malformed infants (≥37 weeks), SGA-related RRs of several neonatal morbidities were higher in within-sibling than in population analyses.

CONCLUSIONS

Perinatal risks associated with fetal growth restriction are more accurately estimated from analyses of SGA in which genetic factors are accounted for.