Constriction of fetal ductus arteriosus by non-steroidal anti-inflammatory drugs

Transplacental effects of 24 non-steroidal anti-inflammatory drugs (NSAIDs) on the fetal ductus arteriosus were studied in full-term pregnant rats using the whole-body freezing technique. All sixteen acidic NSAIDs constricted the fetal ductus in a dose-dependent relationship, but considerable differences in the intensity of effect was noticed with the clinical dose of each drug. Six of the eight basic NSAIDs did not constrict the fetal ductus at 50 to 100 times the usual clinical dose. It is concluded that acidic NSAIDs probably should not be administered to pregnant women. However, it may be established in the future that some basic NSAIDs can be administered safely to pregnant women without hazardous effect on the fetus.