[Fetal malformations caused by oral anticoagulants during pregnancy. Report of a case].

The case of a newborn infant girl with a partial agenesis of the corpus callosum and hypoplasia of the nasal bones is reported. She was the product of a full-term pregnancy of a woman who had previously undergone mitral valve replacement with a Björk-Shiley prosthesis and had been maintained on oral anticoagulants (sodium warfarin) until the 38th week of gestation. This case underlines: 1) The need for maintaining an adequate anticoagulation in pregnant women with a mechanical prosthesis. 2) The potential risks of fetal malformations when the oral anticoagulants are given during the first trimester of pregnancy and of fetal hemorrhagic complications when these drugs are administered during the last two trimesters of gestation. 3) The lack of effective pharmacological alternatives to coumarin drugs, which can allow an adequate anticoagulation in the mother with minimal hazards for the fetus.