Maternal contamination with dichlorodiphenyltrichloroethane and reproductive outcomes in an Australian population

Persistent organochlorine pesticides, such as dichlorodiphenyltrichloroethane (DDT), are lipophilic environmental pollutants which accumulate in the food chain. These chemicals have long half-lives and can be detected in human milk, serum, and some other tissues. These chemicals have recently been under scrutiny for their possible health hazards such as cancer and reproductive outcomes including low birth weight. The aim of our study was to investigate whether mothers with a higher contamination of pesticides were different from mothers with low contamination in relation to their offspringʹs birth outcomes such as birth weight, small for gestation age, prematurity, head circumference, sex ratio, and previous miscarriage or still birth. We used data collected as part of a cross-sectional study of organochlorines in breast milk. This study did not show any association between low birth weight or small for gestation age and organochlorine contamination when comparing the higher to the low exposure group. Weak, significant correlations (−0.1) were detected between low birth weight and contamination levels of dichlorodiphenyldichloroethylene (DDE) only in female offspring. There was a decrease in the percentage of female offspring for all chemicals in the high-contamination group. The babyʹs head circumference increased as the motherʹs contamination increased but the adjusted difference in means was not significant. We did not see any association between either miscarriage or stillbirth in the motherʹs previous pregnancies or prematurity of the first live (recent) baby when comparing the higher to the low exposure mothers. The organochlorines DDT and DDE were not found to be associated with adverse birth outcomes in contaminated mothers in the range of contamination of our population (<7.5 mg/kg lipid in maternal milk), although there is weak evidence that sex ratio may be affected.