Specific congenital malformations after exposure to cyclophosphamide, epirubicin and 5-fluorouracil during the first trimester of pregnancy.

The treatment of pregnant women with chemotherapeutic drugs leads to congenital malformations in 10-20% of newborn children. We present a case of an ongoing 19-week-long pregnancy which was diagnosed in a 39-year-old woman who was being treated with CEF (cyclophosphamide, epirubicin, 5-fluorouracil) chemotherapy for an infiltrating ductal carcinoma of the breast. After termination of the pregnancy, subsequent examination of the fetus revealed micrognathia and bilateral malformations of the hands and feet. The peak exposure of the fetus to the chemotherapeutic agents was in the 5th to 6th week of the pregnancy. Both the nature of the malformations and the timing of the administration of chemotherapy are similar to another case reported previously. We conclude that chemotherapy treatments with CEF in the 5th to 6th week of pregnancy specifically generate hand and foot abnormalities and micrognathia, which is consistent with an inhibition of proliferation, leading to cell death at this embryonic stage.