Background: Cyclooxygenase-2 inhibitors might have fewer adverse fetal effects than conventional nonsteroidal anti-inflammatory drugs that inhibit both isoforms of the enzyme. Although cyclooxygenase-2 is expressed in fetal kidneys, there are no reports of adverse effects in human pregnancy.
Case: A 27-year-old woman, gravida 2, para 0, with a twin pregnancy at 24 weeks' gestation had placement of a cervical cerclage. Nimesulide was prescribed for postoperative preterm labor prophylaxis. Three weeks later, severe oligohydramnios was identified in both sacs, despite normal growth, renal anatomy, and umbilical artery and renal artery Doppler flow velocimetry. After stopping the drug, amniotic fluid volumes returned to normal over 2 weeks. There were no adverse neonatal renal effects.
Conclusion: Selective cyclooxygenase-2 inhibition might cause severe oligohydramnios. If it is used, we advise close fetal surveillance.