Objectives This study investigated the role of maternal exposures at work during pregnancy in the occurrence of oral clefts. MethodsThe occupational exposures of 851 women (100 mothers of babies with oral clefts and 751 mothers of healthy referents) who worked during the first trimester of pregnancy were studied. All the women were part of a multicenter European case-referent study conducted using 6 congenital malfolmation registers between 1989 and 1992. In each center, the mother's occupational histoty, obtained from an interview, was reviewed by industrial hygienists who were blinded to the subject's status and who assessed the presence of chemicals and the probability of exposure. Odds ratios (OR) were estimated by a multivariate analysis including maternal occupation or occupational exposures during the first trimester of pregnancy and possible confounding factors such as center of recruitment, maternal age, urbanization, socioeconomic status, and country of origin.Results After adjustment for confounding factors, cleft palate only was significantly associated with maternal occupation in services such as hairdressing [OR 5.1,95% confidence interval (95% CI) 1.0-26.01 and housekeeping (OR 2.8,95% CI 1.1-7.2). The analysis suggests that the following occupational exposures are associated with orofacial clefts: aliphatic aldehydes (OR 2.1,95% CI 0.8-5.9) and glycol ethers (OR 1.7,95% CI 0.9-3.3) for cleft lip with or without cleft palate and lead compounds (OR 4.0,95% CI 1.3-12.2), biocides (OR 2.5,95% CI 1.0-6.0), antineoplastic drugs (OR 5.0,95% CI 0.8-34.0), trichloroethylene (OR 6.7,95% CI 0.949.7), and aliphatic acids (OR 6.0,95% CI 1.5-22.8) for cleft palate only. C O~C I U S~O~SDue to the limited number of subjects, these results must be interpreted with caution. However, they point out some chemicals already known or suspected as reproductive toxins. [E-mail: lorente@vjf.inserm.fr] multifactorial in origin and are caused by both genetic and environmental factors. Many genetic (risk of Scand J Work Environ Health 2000, vol26, no 2 Key terms 137in Europe (1). Investigators agree that oral clefts are recurrence) and epidemiologic (sex ratio, prevalence)

Objectives. This study examined the relationship between maternal tobacco and alcohol consumption during the first trimester of pregnancy and oral clefts.Methods. Data were derived from a European multicenter case-control study including 161 infants with oral clefts and 1134 control infants.Results. Multivariate analyses showed an increased risk of cleft lip with or without cleft palate associated with smoking (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.07, 3.04) and an increased risk of cleft palate associated with alcohol consumption (OR = 2.28, 95% CI = 1.02, 5.09). The former risk increased with the number of cigarettes smoked.Conclusions. This study provides further evidence of the possible role of prevalent environmental exposures such as tobacco and alcohol in the etiology of oral clefts.