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

Objective: To examine the association between DDT (dichlorodiphenyl trichloroethane) and HCH (hexachlorocyclohexane) exposure and intrauterine growth retardation (IUGR, < 10th percentile of birth weight for gestational age). Method: 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 (Ni-63). The adjusted odds ratios (ORs) for these pesticides in mothers and infants were determined by multiple logistic regression. Results: 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. Conclusion: Exposure of pregnant women to organochlorine pesticides may increase the risk of IUGR, which is a contributing factor for infant mortality in India.