Flaring from Unconventional Oil and Gas Development and Birth Outcomes in the Eagle Ford Shale in South Texas

BACKGROUND: Prior studies suggest exposure to oil and gas development (OGD) adversely affects birth outcomes, but no studies have examined flaring—the open combustion of natural gas—from OGD. OBJECTIVES: We investigated whether residential proximity to flaring from OGD was associated with shorter gestation and reduced fetal growth in the Eagle Ford Shale of south Texas. METHODS: We conducted a retrospective cohort study using administrative birth records from 2012 to 2015 ([Formula: see text]) and satellite observations of flaring activity during pregnancy within [Formula: see text] of maternal residence. Multivariate logistic and linear regression models were used to estimate associations between four outcomes (preterm birth, small-for-gestational age, continuous gestational age, and term birthweight) and exposure to a low (1–9) or high ([Formula: see text]) number of nightly flare events, as compared with no exposure, while controlling for known maternal risk factors. We also examined associations with the number of oil and gas wells within [Formula: see text] using data from DrillingInfo (now Enverus). RESULTS: Exposure to a high number of nightly flare events was associated with a 50% higher odds of preterm birth [[Formula: see text] (95% CI: 1.23, 1.83)] and shorter gestation [[Formula: see text] (95% CI: [Formula: see text] , [Formula: see text]) d] compared with no exposure. Effect estimates were slightly reduced after adjustment for the number of wells within [Formula: see text]. In stratified models these associations were present only among Hispanic women. Flaring and fetal growth outcomes were not significantly associated. Women exposed to a high number of wells (fourth quartile, [Formula: see text]) vs. no wells within [Formula: see text] had a higher odds of preterm birth [[Formula: see text] (95% CI: 1.14, 1.49)], shorter gestation [[Formula: see text] (95% CI: [Formula: see text] , [Formula: see text]) d], and lower average birthweight [[Formula: see text] (95% CI: [Formula: see text] , [Formula: see text]) g]. DISCUSSION: Our study suggests exposure to flaring from OGD is associated with an increased risk of preterm birth. Our findings need to be confirmed in other populations. https://doi.org/10.1289/EHP6394