Additional effect of drinking water endocrine-disrupting compound exposure on fetal growth compared to the effect of active tobacco exposure during pregnancy

Abstract

BackgroundActive tobacco exposure during pregnancy is known to be an important determinant of fetal growth.Nitrates and atrazine metabolites in drinking water may affect fetal growth as a mixture of endocrine disruptors (ED). Our aim was to determine whether ED have an additional effect on fetal growth compared to the known and observed effect of active tobacco exposure during pregnancy. MethodsA historic cohort study was carried out with a sample stratified with regard to maternity ward, drinking water exposure and year of birth. The women included were living in Deux-Sèvres, had given birth between 2005 and 2010 in three selected maternity wards, and ultrasound data from pregnancy were available in their obstetrical records. Mixed linear models were used to analyze fetal weight evolution from second trimester of pregnancy to time of birth according to drinking water exposure to atrazine metabolite and nitrate mixture and active tobacco exposure. ResultsWe included 558 mother-neonate couples, of whom 8.5% were exposed to high doses of mixture and 20.5% to active tobacco smoking. There was no significant difference in fetal weight evolution according to drinking water mixture exposure (0.97 g; 95% CI [-3.01;4.94]) and when comparing nested models with and without drinking water mixture exposure, the likelihood ratio (LR) test was not significant (LR khi²=6.6, p=0.252). ConclusionWe could not show a supplementary effect of mixture exposure on fetal growth as compared to active tobacco exposure. Further research is needed, using more precise methods to estimate ED exposure.