Grandmaternal pregnancy endocrine disruption, low birth weight, and premature birth

Abstract

OPS 16: Chemical exposures and birth outcomes, Room 114, Floor 1, August 28, 2019, 10:30 AM - 12:00 PM Background/Aims Low birth weight (LBW; <2500g) and premature birth (<37 weeks) are major determinants of illnesses later in life. Diethylstilbestrol (DES), an endocrine disrupting chemical (EDC), is a synthetic, nonsteroidal estrogen. It was administered to nearly two million pregnant women in the US alone through the early 1970s, under the mistaken belief that it would prevent pregnancy complications and miscarriages. Though several studies recently have linked prenatal exposure to other EDCs and risks of LBW and premature birth, no three-generation studies examine the association between grandmaternal exposure to endocrine disruptors in pregnancy and risks of these outcomes in grandchildren. Methods: We analyzed data from Nurses’ Health Study (NHS) II participants (born 1946-1964). In 1993, nurses (F1) were asked whether their mother (F0) used DES during her pregnancy with them. Nurses’ children’s (F2) birth weight was queried in 2001. In the present study, we defined LBW as <5.5 pounds. Data were analyzed using cluster-weighted generalized estimating equations with a logit link. Results: Among 47,321 F0 grandmother-F1 mother pairs the prevalence of F0 use of DES during pregnancy was 1.85%. Of 106,631 F2 children, 3,808 (3.57%) were categorized as LBW and 6892 (6.48%) premature. Grandmaternal use of DES during pregnancy was associated with an increased risk of LBW (adjusted odds ratio [aOR] =1.60; 95% CI: 1.23-2.08) and prematurity (aOR=2.67; 95% CI: 2.21-3.21) among grandchildren even after accounting for potential mediating factors, such as F1 mother’s birth weight. The LBW association attenuated after adjusting for gestational age. Conclusion: Maternal prenatal exposure to DES is associated with an increased risk of premature birth and LBW even after adjusting for gestational age. This suggests a relation with both premature birth and intrauterine growth.