Agenesis of the cloacal membrane. A probable teratogenic anomaly.

Five infants with a rare and distinct malformation complex were encountered in a single community within a 7 1/2-month period. Only seven previous reports of this condition were found in the 54-year period between 1926 and 1980. The principal findings in the previously published cases were absence of external genitalia, urinary, genital, and anal orifices, and persistence of the cloaca. This report documents the occurrence of the syndrome in a temporal and regional cluster. Detailed morphologic evaluation of each infant provides the basis for a theory of embryogenesis of the complex, and preliminary data suggest a teratogenic cause. Embryonic exposure to doxylamine succinate within the first 50 days of the pregnancy was certain in three and was probable in two of the five pregnancies.