Risk level in pregnancy: This medicine is classified as Category C.
Nifedipine has shown in laboratory animals teratogenic and toxic effects to the embryo, fetus and placenta, including fetal dystrophies, abnormalities in the fingers similar to those produced by phenytoin, rib deformities, cracks on the palate and various placental changes. There has also been increased fetal and neonatal mortality and prolonged gestation. Experimental doses used were generally higher than the therapeutic doses in humans, but not in all cases.
In humans, there have been isolated observations of perinatal anoxia, increased cesarean delivery, prematurity and intrauterine growth retardation. There are no studies of good methodology on the use of nifedipine in pregnant women.
Meaning of category C
Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.