Exposure to Endocrine-Disrupting Chemicals Can Increase Risk of Postpartum Depression

Melanie Jacobson, PhD, MPH

Results of a new study indicate exposure to endocrine-disrupting chemicals during pregnancy could be contributing to postpartum depression.

Performed by investigators at NYU Langone, the study establishes a link between levels of bisphenols and phthalates in urine samples during early- and mid-pregnancy and hormonal shifts during pregnancy that could contribute to postpartum depression.

"We found that phthalate exposure was associated with lower progesterone levels during pregnancy and a greater likelihood of developing postpartum depression," said study investigator Melanie Jacobson, PhD, MPH, a research scientist with the Environmental Pediatrics Team at the NYU Langone Medical Center, in a statement. "This research is important because phthalates are so prevalent in the environment that they are detectable in nearly all pregnant women in the United States. If these chemicals can affect prenatal hormone levels and subsequently postpartum depression, reducing exposure to these types of chemicals could be a plausible avenue for preventing postpartum depression."

With an interest in examining associations between exposure to endocrine-disrupting chemicals and postpartum depression, the current study was embedded within the NYU Children’s Health and Environment Study (CHES), which is an ongoing longitudinal study of pregnant women and their children that is part of the Environmental Influences on Child Health Outcomes (ECHO) program. Investigators designed this portion of CHES with the intent of evaluating associations between measurements of urinary bisphenols and phthalates in early- and mid-pregnancy with serum pregnenolone, progesterone, allopregnanolone, and pregnanolone concentrations in mid-pregnancy and postpartum depression symptoms 4 months postpartum.

Patients included in the study were pregnant women at least 18 years of age or older, be at 18 weeks of gestation or less, and have non-medically threatened pregnancies. All patients included in the study received prenatal care at NYU Langone Hospital-Manhattan, NYU Langone-Brooklyn, and Bellevue Hospital Center.

For the study, urine and serum samples were collected prior to reaching 18 weeks’ gestation and again at 18-25 weeks’ gestation. Women included in the trial also completed questionnaires, which contained Edinburgh Postnatal Depression Scale (EPDS), during each trimester of pregnancy. For analysis, postpartum depression was considered having a score of 10 or greater. In total, 139 women were identified for inclusion in the final analysis; of these, 12 (8.9%) had an EPDS score of 10 or greater.

Upon analysis, investigators found Di-n-octyl phthalate (DnOP) and diisononyl phthalate (DiNP) metabolites were associated with reduced progesterone concentrations. Results indicated log-unit increases in ∑DnOP and ∑DiNP predicted 8.1% (95% CI, -15.2 to -0.4%) and 7.7% (95% CI, -13.3 to -1.7%) lower progesterone, respectively. Additionally, results suggested ∑DnOP levels were associated with increased odds of postpartum depression (OR, 1.48; 95% CI, 1.04-2.11).

Investigators noted results of the current study should not be overinterpreted and the subject of whether endocrine-disrupting chemicals could influence risk of postpartum depression needs to be researched further.

"These results need to be interpreted with caution as this is the first study to examine these chemicals in relation to postpartum depression and our sample size was small," Jacobson added.

This study, “Prenatal exposure to bisphenols and phthalates and postpartum depression: The role of neurosteroid hormone disruption,” was published in the Journal of Clinical Endocrinology & Metabolism.