Factors associated with late fetal mortality

Neonatal mortality risk of vulnerable newborns by fine stratum of gestational age and birthweight for 230 679 live births in nine low- and middle-income countries, 2000-2017

OBJECTIVE

To describe the mortality risks by fine strata of gestational age and birthweight among 230 679 live births in nine low- and middle-income countries (LMICs) from 2000 to 2017.

DESIGN

Descriptive multi-country secondary data analysis.

SETTING

Nine LMICs in sub-Saharan Africa, Southern and Eastern Asia, and Latin America.

POPULATION

Liveborn infants from 15 population-based cohorts.

METHODS

Subnational, population-based studies with high-quality birth outcome data were invited to join the Vulnerable Newborn Measurement Collaboration. All studies included birthweight, gestational age measured by ultrasound or last menstrual period, infant sex and neonatal survival. We defined adequate birthweight as 2500-3999 g (reference category), macrosomia as ≥4000 g, moderate low as 1500-2499 g and very low birthweight as <1500 g. We analysed fine strata classifications of preterm, term and post-term: ≥42+0 , 39+0 -41+6 (reference category), 37+0 -38+6 , 34+0 -36+6 ,34+0 -36+6 ,32+0 -33+6 , 30+0 -31+6 , 28+0 -29+6 and less than 28 weeks.

MAIN OUTCOME MEASURES

Median and interquartile ranges by study for neonatal mortality rates (NMR) and relative risks (RR). We also performed meta-analysis for the relative mortality risks with 95% confidence intervals (CIs) by the fine categories, stratified by regional study setting (sub-Saharan Africa and Southern Asia) and study-level NMR (≤25 versus >25 neonatal deaths per 1000 live births).

RESULTS

We found a dose-response relationship between lower gestational ages and birthweights with increasing neonatal mortality risks. The highest NMR and RR were among preterm babies born at <28 weeks (median NMR 359.2 per 1000 live births; RR 18.0, 95% CI 8.6-37.6) and very low birthweight (462.8 per 1000 live births; RR 43.4, 95% CI 29.5-63.9). We found no statistically significant neonatal mortality risk for macrosomia (RR 1.1, 95% CI 0.6-3.0) but a statistically significant risk for all preterm babies, post-term babies (RR 1.3, 95% CI 1.1-1.5) and babies born at 370 -386  weeks (RR 1.2, 95% CI 1.0-1.4). There were no statistically significant differences by region or underlying neonatal mortality.

CONCLUSIONS

In addition to tracking vulnerable newborn types, monitoring finer categories of birthweight and gestational age will allow for better understanding of the predictors, interventions and health outcomes for vulnerable newborns. It is imperative that all newborns from live births and stillbirths have an accurate recorded weight and gestational age to track maternal and neonatal health and optimise prevention and care of vulnerable newborns.

Prevalence and Mode of Birth in Late Fetal Mortality in Spain, 2016-2019

(1) Background: The rate of cesarean sections in late fetal mortality remains high. We aimed to determine the prevalence of late fetal mortality in Spain and risk factors for cesarean birth in women with stillbirth ≥ 28 weeks gestation between 2016-2019. (2) Methods: A retrospective observational study with national data between 2016-2019. A total of 3504 births with fetal dead were included. Sociodemographic, obstetrical and neonatal variables were analyzed using univariate and multivariate logistic regression (MLR), with cesarean birth with a stillborn ≥ 28 weeks gestation as the dependent variable. (3) Results: The late fetal mortality rate was 2.8 × 1000; 22.7% of births were by cesarean section. Factors associated with cesarean were having a multiple birth (aOR 6.78); stillbirth weight (aOR 2.41); birth taking place in towns with over 50,000 inhabitants (aOR 1.34); and mother's age ≥ 35 (aOR 1.23). (4) Conclusions: The late fetal mortality rate increased during the period. The performance of cesarean sections was associated with the mother's age, obstetric factors and place of birth. Our findings encourage reflection on how to best put into practice national clinical and socio-educational prevention strategies, as well as the approved protocols on how childbirth should be correctly conducted.

Fetal overgrowth in pregnancies complicated by diabetes: validation of a predictive index in an external cohort

PURPOSE

To assess validity of a fetal overgrowth index in an external cohort of women with diabetes in pregnancy METHODS: We performed a retrospective analysis of data derived from women with singleton gestations complicated by diabetes who delivered January 2015-June 2018. The following index variables were used to calculate risk of fetal overgrowth as defined by a customized birthweight ≥ 90th centile: age, history of fetal overgrowth in a prior pregnancy, gestational weight gain, fetal abdominal circumference measurement and fasting glucose between 24 and 30 weeks.

RESULTS

In our validation cohort, 21% of 477 pregnancies were complicated by fetal overgrowth. The predictive index had a bias-corrected bootstrapped area under receiver operating characteristic curve of 0.90 (95% CI 0.86-0.93). 55% of the cohort had a low-risk index (≤ 3) which had a negative predictive value of 97% (95% CI 94-98%), while 18% had a high-risk index (≥ 8) that had a positive predictive value of 74% (95% CI 66-81%).

CONCLUSION

The fetal overgrowth index incorporates five factors that are widely available in daily clinical practice prior to the period of maximum fetal growth velocity in the third trimester. Despite substantial differences between our cohort and the one studied for model development, we found the performance of the index was strong. This finding lends support for the general use of this tool that may aid counseling and allow for targeted allocation of healthcare resources among women with pregnancies complicated by diabetes.

Perinatal outcome of appropriate-weight fetuses with decelerating growth

INTRODUCTION

To assess the perinatal outcome of fetuses dropping by ≥50 estimated fetal weight (EFW) centiles between the second and third trimester.

METHODS

Singleton pregnancies progressing after 32 + 0 weeks, who had their second- and third-trimester scans at our institutions were enrolled in the study. The perinatal outcome of AGA fetuses crossing more than 50 centiles was compared to that of fetuses with FGR, small for gestational age (SGA) and nondecelerating appropriate for gestational age (AGA). The primary perinatal outcomes were perinatal death, neonatal intensive care (NICU) admission and emergency cesarean section (CS). The rates of these outcomes were compared between the four groups and regression analysis was performed to account for maternal and fetal confounders.

RESULTS

Our analysis included 4394 cases. Compared to nondecelerating SGA, fetuses crossing ≥50 centiles had higher rates of NICU admission (odds ratio [OR] 1.8, 95% confidence interval [CI] CI 1.1-3.1) and perinatal death (OR 3.8, 95%CI 1.3-11.4). Regression analysis showed that significant independent predictors for NICU admission included maternal age, gestational age at birth and FGR (area under the curve [AUC] 0.851), whereas significant predictors for perinatal death included maternal age, gestational age at birth, decelerating growth ≥50 centiles, conception through ART and third-trimester CPR centile (AUC 0.801).

CONCLUSION

AGA fetuses that cross >50 EFW centiles between the second and third trimester are at increased risk of adverse perinatal outcome and it seems advisable that they are followed up as typical FGR cases.