Association between pesticide usage during pregnancy and neonatal hyperbilirubinemia requiring treatment: the Japan Environment and Children’s Study

Background Maternal exposure to pesticides during pregnancy may cause oxidative hemolysis leading to neonatal hyperbilirubinemia. This investigation examined for associations between maternal use of pesticides or repellents during pregnancy and neonatal hyperbilirubinemia requiring phototherapy. Methods We used the dataset from the Japan Environment and Children’s Study, a large national birth cohort study registered from January 31, 2011 to March 31, 2014. The fixed data of 61,751 live births were used to evaluate the presence of neonatal hyperbilirubinemia and potential confounding factors. We employed multiple logistic regression analysis to identify correlations between the frequency of maternal pesticide or repellent use during pregnancy and clinically relevant neonatal hyperbilirubinemia. Results After controlling for confounding factors, there were significant associations between neonatal hyperbilirubinemia necessitating phototherapy and the frequent use of indoor insecticide spray (OR 1.21, 95% CI 1.05–1.38). For spray- or lotion-type insect repellents, an opposite relationship was observed (more than a few times a week: OR 0.70, 95% CI 0.61–0.81, up to a few times a month: OR 0.84, 95% CI 0.78–0.91). Conclusion The frequent use of indoor insecticide spray during pregnancy showed an increased risk of neonatal hyperbilirubinemia requiring phototherapy, which was absent for spray- or lotion-type insect repellents. Impact The frequent use of indoor insecticide spray during pregnancy showed an increased risk of neonatal hyperbilirubinemia requiring phototherapy, which was absent for spray- or lotion-type insect repellents. This is the first study examining the effects of maternal exposure to pesticides or repellents on clinically relevant neonatal hyperbilirubinemia using a dataset from a nationwide birth cohort study. This large-scale Japanese cohort study revealed that the frequent use of indoor insecticide spray during pregnancy may increase the risk of neonatal hyperbilirubinemia requiring treatment.