Persistent chlorinated pesticides and intra-uterine foetal growth retardation: a possible association

To examine the association between DDT (dichlorodiphenyl trichloroethane) and HCH (hexachlorocyclohexane) exposure and intra-uterine growth retardation (IUGR, <10th percentile of birth weight for gestational age).

We detected p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE and alpha-HCH, beta-HCH, gamma-HCH, delta-HCH in maternal blood, placenta and cord blood, collected at parturition, from mothers with IUGR babies ( n=30) and from those with babies of normal weight ( n=24), using gas-liquid chromatography equipped with electron capture detector ((63)Ni). The adjusted odds ratios (ORs) for these pesticides in mothers and infants were determined by multiple logistic regression.

There were statistically significant associations ( P<0.05) between maternal blood levels of alpha-HCH (OR=1.22; 95% CI: 1.02-1.46), gamma-HCH (OR=1.38; 95%CI: 1.05-1.80), delta-HCH (OR=1.61; 95% CI: 1.01-2.54), total HCH (OR=1.07; 95% CI: 1.01-1.13) and p,p'-DDE (OR=1.21; 95%CI:1.03-1.42) and IUGR after adjustment for potential confounders. Also, significant association (P<0.05) between cord blood levels of gamma-HCH (OR=1.14; 95% CI: 1.00-1.31), delta-HCH (OR=1.31; 95% CI: 1.00-1.75), total HCH (OR=1.07; 95% CI: 1.00-1.14) and IUGR were found after adjustment for potential confounders. A significant negative correlation between body weight of newborn babies and p,p'-DDE in maternal blood (r= -0.25; P<0.05) and delta-HCH and p,p'-DDE in the cord blood (r= -0.27 and -0.26; P<0.05) was noticed after gestational age had been accounted for.

Exposure of pregnant women to organochlorine pesticides may increase the risk of IUGR, which is a contributing factor for infant mortality in India.