Self-reported oil spill exposure and birth outcomes among southern Louisiana women at the time of the Gulf oil spill: The GROWH study

Background: The chemical, physical, economic, and social effects of a major oil spill might adversely affect pregnancy health. Objectives: To examine the relationship between oil spill exposure and birth outcomes in a cohort of women living near the Gulf of Mexico at the time of the 2010 oil spill. Methods: Between 2012 and 2016, 1375 women reported their exposure to the oil spill, and at least one livebirth. Five hundred and three had births both before and after the oil spill. Indicators of oil spill exposure included selfreported financial consequences, direct contact with oil, traumatic experiences, loss of use of the coast, and involvement in litigation. Birth outcomes were low birthweight (LBW; birthweight <2500 g) and preterm birth (PTB; >3 weeks early). Women who were not pregnant at the time of the interview (n = 1001) self-reported outcomes, while women who were pregnant (n = 374) primarily had them abstracted from medical records (n = 374). All pregnancies prior to the oil spill were considered unexposed; those after the oil spill were considered exposed or unexposed depending on interview responses. Generalized estimating equations were used to control for clustering within women, with control for confounders. Results: The most common type of exposure was economic (49%), but 302 women (22.0%) reported some degree of direct contact with the oil. Associations between most indicators of oil spill exposure and pregnancy outcomes were null, although when all pregnancies were examined, associations were seen with high levels of contact with oil for LBW (adjusted Odds Ratio [aOR] 2.19, 95% CI, 1.29-3.71) and PTB (aOR 2.27, 1.34-3.87). Discussion: In this community-based cohort, we did not find associations between report of exposure to the oil spill, with the possible exception of high oil contact in some analyses, and birth outcomes. Research incorporating specific biomarkers of oil spill exposure and stress biomarkers would be valuable, to allow for assessing both perceived and actual exposure, especially when direct toxicant exposure is minimal.