Determinants of Reproductive Health: Nutrition and Environmental Influences

Leveraging the rich longitudinal data from the NICHD Fetal Growth Studies, my team has examined how adherence to established healthy dietary patterns, i.e., the Alternate Healthy Eating Index (AHEI), alternate Mediterranean diet (AMED), Healthy Eating Index [HEI], and Dietary Approaches to Stop Hypertension (DASH), relates to pregnancy complications and neonatal outcomes. More recently, we evaluated a novel dietary pattern, the Planetary Health Diet (PHD), introduced by the EAT-Lancet Commission in 2019. The PHD emphasizes plant-based foods with moderate intake of animal-based products and is uniquely informed by considerations of the environmental impact of each food group.

In a study examining adherence to these dietary patterns and gestational weight gain, we found that greater adherence to several healthy diets, including DASH, AMED, HEI, and AHEI, was associated with lower odds of inadequate gestational weight gain. In a second study, we assessed whether high peri-conceptional and early pregnancy adherence to the PHD was associated with fetal growth patterns, using longitudinal 2D and 3D fetal biometric measures from the NICHD Fetal Growth Studies and the Fetal 3D Study. Among this low-risk cohort, higher adherence to the PHD was associated with greater fetal adiposity and reduced lean tissue, reflected in larger fractional arm volumes in the second trimester and greater fetal weight and abdominal measures in the third trimester.

The health consequences of extreme weather are increasingly recognized, yet important gaps remain in understanding its effects on fertility, pregnancy, and childbirth. To address this gap, we developed a first-of-its-kind database that integrates data from large-scale pre-conception and pregnancy cohorts across multiple recent DiPHR studies with longitudinal weather indicators characterized by fine geographic and temporal resolution. This resource uniquely enables population-level investigation of how extreme weather influences reproductive and perinatal health.

Using these data, our team examined associations between exposure to extreme hot and cold ambient temperatures during pregnancy and preterm birth. We found that both chronic heat and chronic cold exposure were associated with an increased risk of early preterm birth (gestational age of under 34 weeks), with the risk rising monotonically as the proportion of days with extreme temperature exposure increased (Figure 1). These findings have important implications for clinical care and public health, particularly as climate projections indicate that extreme temperatures will become more frequent and severe. As a result, a growing number of pregnancies may face elevated risk of early delivery and subsequent adverse health outcomes in offspring.