Second- and third-trimester exposure to angiotensinconverting
enzyme inhibitors appears to be fetotoxic, producing
fetal hypocalvaria and renal defects. The cause of these defects
seems to be related to fetal hypotension and reduced renal
blood flow. Anuria associated with oligohydramnios can produce
fetal limb contractures, craniofacial deformations and pulmonary
hypoplasia. Intrauterine growth restriction, prematurity, persistence
of a patent ductus arteriosus, severe neonatal hypotension,
neonatal anuria and neonatal or fetal death have all been
observed with use of these drugs, and they should therefore be
discontinued preconceptually or as early in the first trimester as
possible.