The association between gestational weight gain z-score and stillbirth: a case-control study

Gestational Weight Gain and Neonatal Biometry during the COVID-19 Pandemic: A Multicenter Observational Cohort

OBJECTIVE

 This study aimed to test the hypothesis that being pregnant and delivering during the coronavirus disease 2019 (COVID-19) pandemic was associated with changes in gestational weight gain (GWG) or frequency of small- (SGA) or large-for-gestational-age (LGA) neonates.

STUDY DESIGN

 Secondary analysis of a multicenter observational cohort comparing pregnant people who delivered during the COVID-19 pandemic (June-December 2020) to people who delivered prior to the pandemic (March-December 2019). Those with multiple gestations, fetuses with major congenital anomalies, implausible GWG values, unavailable body mass index (BMI), or who were severe acute respiratory syndrome coronavirus-2-positive were excluded. The primary outcome was frequency of optimal recommended GWG based on prepregnancy BMI. Neonatal outcomes included birth weight, ponderal index, and frequency of SGA, LGA, and small head circumference for live births. Multivariable regression analysis was used to assess associations between exposure to the pandemic and outcomes.

RESULTS

 A total of 10,717 pregnant people were included in our analysis. A total of 4,225 pregnant people were exposed to the pandemic and 6,492 pregnant people delivered prior to the COVID-19 pandemic. Pregnant people exposed to the pandemic were older and more likely to have gestational diabetes. The frequency of appropriate GWG was 28.0% during the pandemic and 27.6% before the pandemic (adjusted odds ratio [aOR]: 1.02, 95% confidence interval [CI]: 0.93-1.11). Excessive GWG was more likely (54.9 vs. 53.1%; aOR: 1.08, 95% CI: 1.001-1.17), and inadequate GWG was less likely during the pandemic (17.0 vs. 19.3%; aOR: 0.86, 95% CI: 0.77-0.95). The frequency of SGA was 5.4% during the pandemic and 6.1% before the pandemic (aOR: 0.90, 95% CI: 0.76-1.06), and the frequency of LGA was 16.0% during the pandemic versus 15.0% before the pandemic (aOR: 1.06, 95% CI: 0.95-1.18). Other neonatal outcomes including birth weight percentile (62.1 [35.8-83.2] vs. 60.2 [34.4-82.2]; adjusted mean difference (aMD) = 1.50, 95% CI: -0.28 to 3.29), ponderal index (2.6 g/cm3 [2.4-2.8] in both groups; aMD = 0.01, 95% CI: 0.00-0.02), and small head circumference for livebirths (<10th percentile [8.2 vs. 8.1%; aOR: 1.03, 95% CI: 0.89-1.19], <3rd percentile [3.5 vs. 3.1%; aOR: 1.16, 95% CI: 0.93-1.44]) were similar between groups as well.

CONCLUSION

 Being pregnant and delivering during the COVID-19 pandemic was associated with a higher likelihood of excessive GWG and a lower likelihood of inadequate GWG.

KEY POINTS

· Delivering during the COVID-19 pandemic was associated with higher likelihood of excessive GWG.. · Delivering during the COVID-19 pandemic was associated with lower likelihood of inadequate GWG.. · COVID-19 pandemic was not associated with changes in frequency of SGA or LGA..

Suboptimal gestational weight gain and neonatal outcomes in low and middle income countries: individual participant data meta-analysis

OBJECTIVE

To estimate the associations between gestational weight gain (GWG) during pregnancy and neonatal outcomes in low and middle income countries.

DESIGN

Individual participant data meta-analysis.

SETTING

Prospective pregnancy studies from 24 low and middle income countries.

MAIN OUTCOME MEASURES

Nine neonatal outcomes related to timing (preterm birth) and anthropometry (weight, length, and head circumference) at birth, stillbirths, and neonatal death.

ANALYSIS METHODS

A systematic search was conducted in PubMed, Embase, and Web of Science which identified 53 prospective pregnancy studies published after the year 2000 with data on GWG, timing and anthropometry at birth, and neonatal mortality. GWG adequacy was defined as the ratio of the observed maternal weight gain over the recommended weight gain based on the Institute of Medicine body mass index specific guidelines, which are derived from data in high income settings, and the INTERGROWTH-21st GWG standards. Study specific estimates, adjusted for confounders, were generated and then pooled using random effects meta-analysis models. Maternal age and body mass index before pregnancy were examined as potential modifiers of the associations between GWG adequacy and neonatal outcomes.

RESULTS

Overall, 55% of participants had severely inadequate (<70%) or moderately inadequate (70% to <90%) GWG, 22% had adequate GWG (90-125%), and 23% had excessive GWG (≥125%). Severely inadequate GWG was associated with a higher risk of low birthweight (adjusted relative risk 1.62, 95% confidence interval 1.51 to 1.72; 48 studies, 93 337 participants; τ2=0.006), small for gestational age (1.44, 1.36 to 1.54; 51 studies, 93 191 participants; τ2=0.016), short for gestational age (1.47, 1.29 to 1.69; 40 studies, 83 827 participants; τ2=0.074), and microcephaly (1.57, 1.31 to 1.88; 31 studies, 80 046 participants; τ2=0.145) compared with adequate GWG. Excessive GWG was associated with a higher risk of preterm birth (1.22, 1.13 to 1.31; 48 studies, 103 762 participants; τ2=0.008), large for gestational age (1.44, 1.33 to 1.57; 47 studies, 90 044 participants; τ2=0.009), and macrosomia (1.52, 1.33 to 1.73; 29 studies, 68 138 participants; τ2=0) compared with adequate GWG. The direction and magnitude of the associations between GWG adequacy and several neonatal outcomes were modified by maternal age and body mass index before pregnancy.

CONCLUSIONS

Inadequate and excessive GWG are associated with a higher risk of adverse neonatal outcomes across settings. Interventions to promote optimal GWG during pregnancy are likely to reduce the burden of adverse neonatal outcomes, however further research is needed to assess optimal ranges of GWG based on data from low and middle income countries.

Gestational Weight Gain and Birth Outcome: A Comparison of Methods of Accounting for Gestational Age

Cross-sectional studies of total gestational weight gain (GWG) and perinatal outcomes have used different approaches to operationalize GWG and adjust for duration of gestation. Using birth records from California (2007-2017), Nevada (2010-2017), and Oregon (2008-2017), we compared 3 commonly used approaches to estimate associations between GWG and cesarean delivery, small-for-gestational-age birth, and low birth weight (LBW): 1) the Institute of Medicine-recommended GWG ranges at a given gestational week, 2) total weight gain categories directly adjusting for gestational age as a covariate, and 3) weight-gain-for-gestational-age z scores derived from an external longitudinal reference population. Among 5,461,130 births, the 3 methods yielded similar conclusions for cesarean delivery and small-for-gestational-age birth. However, for LBW, some associations based on z scores were in the opposite direction of methods 1 and 2, paradoxically suggesting that higher GWG increases risk of LBW. This was due to a greater proportion of preterm births among those with high z scores, and controlling for gestational age in the z score model brought the results in line with the other methods. We conclude that the use of externally derived GWG z scores based on ongoing pregnancies can yield associations confounded by duration of pregnancy when the outcome is strongly associated with gestational age at delivery.

Overweight, obesity and excessive weight gain in pregnancy as risk factors for adverse pregnancy outcomes: a narrative review

The global prevalence of overweight and obesity in pregnancy is rising and this represents a significant challenge for the management of pregnancy and delivery. Women who have a pre‐pregnancy body mass index greater than 25 kg m^–2 are more likely than those with a body mass index in the ideal range (20–24.99 kg m^–2) to have problems conceiving a child and are at greater risk of miscarriage and stillbirth. All pregnancy complications are more likely with overweight, obesity and excessive gestational weight gain, including those that pose a significant threat to the lives of mothers and babies. Labour complications arise more often when pregnancies are complicated by overweight and obesity. Pregnancy is a stage of life when women have greater openness to messages about their lifestyle and health. It is also a time when they come into greater contact with health professionals. Currently management of pregnancy weight gain and the impact of overweight tends to be poor, although a number of research studies have demonstrated that appropriate interventions based around dietary change can be effective in controlling weight gain and reducing the risk of pregnancy complications. The development of individualised and flexible plans for avoiding adverse outcomes of obesity in pregnancy will require investment in training of health professionals and better integration into normal antenatal care.

Overweight and obesity before pregnancy and excessive gestational weight gain are major determinants of risk for pregnancy loss, gestational diabetes, hypertensive conditions, labour complications and maternal death.

Pregnancy is regarded as a teachable moment when women are at their most receptive to messages about their health. However, unclear guidance on diet and physical activity, weight stigma from health professionals, inexperience and reluctance among professionals about raising issues about weight, and stretched resources put the health of women and babies at risk.

Excessive weight gain in pregnancy and post‐partum weight retention compromise future fertility and increase risk for future pregnancies.

Large randomised controlled trials have had little success in addressing excessive gestational weight gain or antenatal complications. Individualised, culturally sensitive and responsive interventions appear to have greater success.

Association of Gestational Weight Gain With Infant Morbidity and Mortality in the United States

IMPORTANCE

The associations of gestational weight gain (GWG) with infant morbidity and mortality are unclear, and the existing recommendations for GWG have not been stratified by the severity of obesity.

OBJECTIVES

To identify optimal GWG ranges associated with reduced risks of infant morbidity and mortality across maternal body mass index (BMI) categories.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used US nationwide, linked birth and infant death data between 2011 and 2015 to assess the associations of GWG in 2.0-kg groups with infant morbidity and mortality and identified optimal GWG ranges associated with reduced risks of both outcomes, using multivariable logistic regression models. Statistical analysis was performed from February 11 to October 14, 2021.

EXPOSURE

Gestational weight gain equivalent to 40 weeks.

MAIN OUTCOMES AND MEASURES

The 2 main outcomes were (1) significant morbidity of the newborn infant, defined as any presence of assisted ventilation, admission to the neonatal intensive care unit, surfactant therapy, antibiotic therapy, or seizures; and (2) infant mortality younger than 1 year of age (<1 hour, 1-23 hours, 1-6 days, 7-27 days, or 28-365 days after birth).

RESULTS

In this study of 15 759 945 mother-infant dyads, the mean (SD) age of the women was 28.1 (5.9) years. Women gained a mean (SD) of 14.1 (7.3) kg during pregnancy, and the mean (SD) GWG decreased with BMI categories (underweight, 15.7 [6.4] kg; normal weight, 15.4 [6.2] kg; overweight, 14.2 [7.4] kg; obesity class 1, 12.2 [8.0] kg; obesity class 2, 10.3 [8.4] kg; obesity class 3, 8.2 [9.2] kg; P < .001). A total of 8.8% of the newborns experienced significant morbidity, with the lowest prevalence among infants delivered by women in the normal weight BMI class (8.0%) and the highest among infants delivered by women with class 3 obesity (12.4%); 0.34% of infants died within 1 year of birth, with the lowest prevalence among infants delivered by women in the normal weight BMI class (0.28%) and the highest among infants delivered by women with class 3 obesity (0.58%). Optimal GWG ranges were 12.0 to less than 24.0 kg for underweight and normal weight women, 10.0 to less than 20.0 kg for overweight women, 8.0 to less than 16.0 kg for women with class 1 obesity, 6.0 to less than 16.0 kg for class 2 obesity, and 6.0 to less than 10.0 kg for class 3 obesity. The lower bounds of the optimal GWG ranges appeared to be higher than the existing recommendations for overweight women (10.0 vs 7.0 kg) and for those with class 1 (8.0 vs 5.0 kg), class 2 (6.0 vs 5.0 kg), and class 3 (6.0 vs 5.0 kg) obesity.

CONCLUSIONS AND RELEVANCE

This study analyzed the associations of GWG with infant morbidity and mortality across BMI categories and found that inadequate GWG was associated with increased risks of adverse infant outcomes even for women with obesity. The results suggested that weight maintenance or weight loss should not be used as routine guidelines.

Cause-Specific Stillbirth and Neonatal Death According to Prepregnancy Obesity and Early Gestational Weight Gain: A Study in the Danish National Birth Cohort

Maternal obesity is associated with impaired fetal and neonatal survival, but underlying mechanisms are poorly understood. We examined how prepregnancy BMI and early gestational weight gain (GWG) were associated with cause-specific stillbirth and neonatal death. In 85,822 pregnancies in the Danish National Birth Cohort (1996–2002), we identified causes of death from medical records for 272 late stillbirths and 228 neonatal deaths. Prepregnancy BMI and early GWG derived from an early pregnancy interview and Cox regression were used to estimate associations with stillbirth or neonatal death as a combined outcome and nine specific cause-of-death categories. Compared to women with normal weight, risk of stillbirth or neonatal death was increased by 66% with overweight and 78% with obesity. Especially deaths due to placental dysfunction, umbilical cord complications, intrapartum events, and infections were increased in women with obesity. More stillbirths and neonatal deaths were observed in women with BMI < 25 and low GWG. Additionally, unexplained intrauterine death was increased with low GWG, while more early stillbirths were seen with both low and high GWG. In conclusion, causes of death that relate to vascular and metabolic disturbances were increased in women with obesity. Low early GWG in women of normal weight deserves more clinical attention.