Placental passage of angiotensin-converting enzyme inhibitors

OBJECTIVE: Placental passage of the angiotensin-converting enzyme inhibitors temocapril and enalapril was investigated in a placental perfusion model. STUDY DESIGN: In an open system a placental lobe was perfused on both the maternal and the fetal side with a blood-free medium containing the test substances plus a reference substance on the maternal side. Six placentas were perfused with temocapril and five with enalapril. The drugs were measured by gas chromatography – mass spectrometry. RESULTS: Both angiotensin-converting enzyme inhibitors crossed the human placenta in the maternal-fetal direction in similar quantities. Temocapril showed the same pharmacokinetic characteristics as enalapril. CONCLUSIONS: This was the first study to quantify the placental transfer of angiotensin-converting enzyme inhibitors. These antihypertensive agents should not be taken during pregnancy, to avoid any potential hazards to the fetus. (AM J OBSTET GYNECOL 1996;174:1450-5.)