Lead Exposure and Maternal Depression Together Contribute to Negative Birth Outcomes, Study Finds

ALBANY, N.Y. (March 3, 2022) — A recent study from the School of Public Health found that pregnant women who experienced depression and had higher levels of lead exposure were more likely to have negative birth outcomes.

Pregnancy is a critical period not only for developing body systems but also for influencing health over the lifespan, according to Allison Appleton, associate professor in Epidemiology and Biostatistics and lead researcher on the study. Independently, exposures and psychological adversities during pregnancy play a role in birth outcomes and long-term health.

The research team collected data from the Albany Infant and Mother Study, an ongoing study of pregnant women and their babies born at Albany Medical Center that began in 2015. Lead exposure was gathered through toenail clippings of the mother, depression was measured via a self-reported screening, infant statistics were measured after birth as is routine and DNA was collected from umbilical cord blood samples. The DNA was collected to look at DNA methylation — a process that is key for DNA repair and gene expression. In particular, this study looked at methylation to the NR3C1 glucocorticoid receptor, a part of the neuroendocrine system that regulates body systems and our responses to stress.

Results showed that higher levels of lead and depression jointly contributed to earlier gestations, smaller infant size at birth and asymmetric fetal growth. Being born small or early may indicate neonatal morbidity and infant mortality risk, as well as enduring physical and mental health risk as a baby grows up. Asymmetry in fetal growth can likewise signal future health risk, particularly neurodevelopmental risk.

“It’s important to note that social and environmental risks do not happen in isolation,” said Appleton. “They co-occur and are likely to affect health outcomes together, not just individually. This is why we examined lead exposure and depression — focusing on more factors within the environment helps not only to improve our estimates on impact, but also to improve the recommendations that doctors make to their pregnant patients as well.”

Maternal lead and depression levels during pregnancy were also jointly associated with variability in NR3C1 methylation, suggesting that the baby’s own stress regulation system that is developing during gestation can be disrupted by these exposures. Changes in NR3C1 methylation may influence how the baby will respond to stressors in its own life.

“NR3C1 methylation can be altered during gestation and then remain relatively stable over time to potentially exert long-term impacts on health and physiologic processes of the child,” Appleton explains. “Our study shows that lead and depression can cumulatively influence birth outcomes and epigenetic mechanisms, which may lay the foundation for health problems later in life.”

The full report can be found in the International Journal of Environmental Research and Public Health.