Industrial chemical exposure during pregnancy and risk of orofacial clefts in the democratic republic of congo

The University of Southern California and Operation Smile are investigating genetic and environmental factors in the etiology of orofacial clefts. Few studies have been conducted on the common birth defect within lower income countries. Children under age three were identified as cases during two Operation Smile missions in Kinshasa, Democratic Republic of Congo (DRC) in 2011 and 2012. Controls were identified as non-cleft newborns at maternity hospitals in Kinshasa. Biological mothers and fathers were enrolled for each case and control. Saliva samples were collected for genetic analysis and self-reported questionnaires on prenatal and lifestyle behaviors were administered to mothers. Maternal responses, utilizing multivariate logistic regression analysis, revealed a statistically significant difference (p=0.002) between case and control mothers on exposure status to industrial chemicals during pregnancy. An adjusted odds ratio (OR 6.9; 95% CI 2.09-22.8) showed an increased risk of orofacial cleft with industrial chemical exposure during pregnancy; adjustments were made for child's gender, age of parents, mother's education level and occupations of parents. Women in DRC may be exposed to higher levels of chemicals due to less regulation of environmental and occupational hazards. Potential study limitations may be due to a small sample size and lack of specific chemical types. These findings suggest that further investigation into types of chemical exposures should be conducted. The future direction of the study is to investigate multiple exposures and translate the results into the development and implementation of preventive measures for orofacial clefts.