Association between maternal serum concentration of the DDT metabolite DDEand preterm and small-for-gestational-age babies at birth

Background DDT (1,1,1-trichloro-2.2-bis(p-chlorophenyl) ethane) is highly e ffective against most malaria-transmitting mosquitoes and is being widely u sed in malaria-endemic areas. The metabolite, DDE (1,1-dichloro-2,2-bis(p-c hlorophenyl)ethylene), has been linked to preterm birth in small studies, b ut these findings are inconclusive. Our aim was to investigate the associat ion between DDE exposure and preterm birth. Methods Our study was based on the US Collaborative Perinatal Project (CPP) . From this study we selected a subset of more than 44 000 eligible childre n born between 1959 and 1966 and measured the DDE concentration in their mo thers' serum samples stored during pregnancy. Complete data were available for 2380 children, of whom 361 were born preterm and 221 were small-for-ges tational age. Findings The median maternal DDE concentration was 25 mug/L (range 3-178)-s everal fold higher than current US concentrations. The adjusted odds ratios (OR) of preterm birth increased steadily with increasing concentrations of serum DDE (ORs=1, 1.5, 1.6, 2.5, 3.1; trend p<0.0001). Adjusted odds of sm all-for-gestational-age also increased, but less consistently (ORs=1, 1.9, 1.7, 1.6, 2.6; trend p=0.04). After excluding preterm births, the associati on of DDE with small-for-gestational-age remained. Interpretation The findings strongly suggest that DDT use increases preterm births, which is a major contributor to infant mortality. If this associat ion is causal, it should be included in any assessment of the costs and ben efits of vector control with DDT.