Fish consumption and maternal hair mercury levels in relation to the risk of preterm delivery

Preterm delivery (PD) has continued to be the leading cause of fetal mortality and morbidity despite extensive etiological studies and advancements in medical technologies. Recently, fish consumption has been hypothesized to be related to decreased risk of PD through the effect of omega-3 fatty acids (n-3 FA). However, other researchers have indicated that mercury, which comes mainly from fish consumption for many human populations has adverse effects on fetal development. This prospective cohort study was based on the Pregnancy Outcome & Community Health (POUCH) Study and assessed the association between maternal fish consumption during the first half of pregnancy and the risk of PD among 1326 pregnant women, and the association between fish consumption and hair mercury levels and the influence of hair mercury levels on the risk of PD among 1031 women who agreed to give hair samples. Results showed that the top 10th percentile of hair mercury levels was significantly associated with increased risk of very PD (<35 weeks) and the 4 th quintile was significantly associated with increased risk of moderately PD (36–37 weeks). Total fish consumption, consumption of canned fish and sport caught fish were significantly associated with increased hair mercury levels. Other maternal characteristics including age, ethnicity, Medicaid status and community of enrollment were also associated with hair mercury levels after adjusting for fish consumption. Total fish consumption was not found to be associated with the risk of PD.