Angiotensin converting enzyme inhibitors use in the first trimester of pregnancy

Angiotensin Converting Enzyme Inhibitors (ACE-I) have been very effective in treating hypertension. Adverse conditions in the fetus with the use of ACE-I, such as oligohydramnios, intra-uterine growth restriction (IUGR), hypocalvaria, persistent ductus arteriosus with fetal and neonatal death have been rerported. Though the pathophysiology was thought to be a problem with renal hypoperfusion in the fetus, it remained unclear whether the first trimester exposure to these drugs produced a similar pattern. We participated in a collaborative trial initiated by the Organization of Teratology Information Services (OTIS) in the United States to examine whether first trimester exposure to ACE-I was of concern. Eight women from our High Risk Pregnancy Unit who delivered in our hospital were enrolled in the trial. All were treated with either Enalapril or Captopril in the first trimester due to various reasons, mainly chronic hypertension and diabetic nephropathy. No major malformations were detected in the nine newborns studied (one pair of twins). Two cases of IUGR were diagnosed, one of them ended in an intra-uterine death, but this was attributed to maternal severe disease and probably not to drug effect. We are definitely not suggesting that women should stay on ACE-I until the second trimester, but it seems that renal blood flow and its associated problems with glomerular filtration are not affected in the first trimester.