Hurricane Michael and adverse birth outcomes

Abstract

Background: Hurricanes and natural disasters are often associated with increases in adverse birth outcomes, due to associated stress, lack of access to medical care, and exposures to environmental toxicants, including harmful algae, chemical spills, and carbon monoxide.Methods: Vital statistics data were used to assess changes in birth outcomes in Florida counties affected by Hurricane Michael (October 2018). Birth outcomes, including low birthweight (LBW; <2500 g) and preterm birth (PTB; <37 weeks' gestation), were compared for one-year periods before and after Michael, and across counties. Paired t-tests and linear regression were used to assess change in number of births. Logistic regression models were used for binary outcomes, and a semi-parametric model and cumulative logistic regression were used for antenatal care (ANC) utilization, adjusting for maternal characteristics.Results: Number of births in the affected area was not statistically different before and after Michael. Change in births was not significantly different across counties affected with differing severity by Michael. In counties most affected, proportion of LBW births rose after Michael (8.2% vs. 9.5%, p<0.01), while PTB did not change (13.75% vs. 13.60%, p=0.79). ANC utilization decreased after Michael, including delayed first ANC visit, decreased proportion of women receiving ANC during pregnancy, and decreased Kotelchuck index. Adjusting for covariates, Odds ratio (OR) for LBW was 1.217 (95%CI: 1.082, 1.367, p<0.01), and OR for PTB was 0.994 (95%CI: 0.898, 1.100, p=0.91); first ANC visit was delayed 0.137 month (95%CI: 0.08, 0.19, p<0.01), OR of receiving any ANC was 0.65 (95%CI: 0.50, 0.86, p<0.01), OR of more adequate ANC was 0.79 (95%CI: 0.738, 0.842, p<0.01). Conclusions: Hurricane Michael was associated with increased risk of late and inadequate ANC and LBW. Ongoing efforts include characterization of potential Hurricane-associated factors which may have contributed to adverse outcomes, including exposures to chemical stressors including harmful algal blooms and carbon monoxide.