Gastrointestinal atresia and maternal occupation during pregnancy.

This study originated in observations in cohort studies that women who worked in laboratories during pregnancy may be at increased risk of having an infant with gut atresia. A case-control study has been made of 201 women who had infants with gastrointestinal atresia and 402 women with infants without that malformation but matched for age, parity and time of year for delivery. Maternal occupation during pregnancy was ascertained by interviews of mailed inquiries and only referred to type of occupation; no efforts to obtain detailed information on occupational exposure were made. Occupation of nonresponders was checked using census data. In the case-control study, laboratory work was reported to occur more often among case mothers than among controls, thus verifying the connection. The actual exposure in the laboratory work giving the embryonic damage is not known.