Congenital anomalies associated with maternal exposure to oxydemeton-methyl.

Thirty-five workers became ill after they entered a cauliflower field contaminated with residues of three different insecticides, the organophosphates oxydemeton-methyl (Metasystox-R) and mevinphos (Phosdrin), and a carbamate, methomyl (Lannate). One crew member was pregnant with a 4-week-old fetus. At birth, the 3200-g female infant had multiple cardiac defects, bilateral optic nerve colobomas, microphthalmia of the left eye, cerebral and cerebellar atrophy, and facial anomalies. The cardiac defects included ventricular and atrial septal defects, stenosis of the pulmonary artery, and a patent ductus arteriosus. The child died at 14 days of age. There was no family history of birth defects, nor any maternal risk factor present, except that doxylamine (Bendectin) had been prescribed at 9 weeks fetal age. It is unlikely that doxylamine was responsible for the observed anomalies. Of the three chemicals involved, reproductive effects in test organisms have been observed only with oxydemeton-methyl. This case represents the first report of human malformations associated with prenatal exposure to this chemical. Further studies may be warranted to determine if a causal relationship exists.