Trimethoprim and Sulfamethoxazole in Pregnancy

To the Editor.— New drugs must be considered as contraindicated during pregnancy, especially at the time of organogenesis. The trimethoprim-sulfamethoxazole combinations (Bactrim, Septrin) are apparently not teratogenic in animals when given in therapeutic doses. However fetal malformation, such as experimental folate deficiency, can be produced by higher doses in rats. The combination of trimethoprim and sulfamethoxazole has been given for the treatment of bacteriuria to a series of 120 pregnant women (ten of these in the first trimester) apparently without evidence of a teratogenic effect. 1 An additional patient has been successfully treated with trimethoprim and sulfamethoxazole without interruption for 14 months, starting six months before pregnancy. A 30-year-old woman, born in Michoacan, Mexico, had an actinomycetic mycetoma of the left foot of 11 years' duration with involvement of the calcaneus. Nocardia brasiliensis was obtained on culture. Since 1965 she had been treated with 300 mg of dapsone per day,