Severe ovarian hyperstimulation syndrome requiring recurrent large-volume paracenteses until 21 weeks' gestation: a case report.

Objective: To report a case of severe ovarian hyperstimulation syndrome (OHSS) persisting into the late second trimester of a singleton pregnancy.

Design: Case report.

Setting: Academic tertiary care center.

Patients: A 29-year-old woman with severe OHSS after fresh embryo transfer after controlled ovarian hyperstimulation requiring intervention until 21 weeks' gestation in a singleton pregnancy.

Interventions: Thorough evaluation of an unusual case of severe OHSS and medical/procedural management of its sequelae in the setting of ongoing pregnancy.

Main Outcome Measuress: The clinical development of severe OHSS during pregnancy and its effect on pregnancy outcomes.

Results: Severe OHSS persisted until 21 weeks' gestation with reaccumulating ascitic fluid, which impacted pregnancy outcomes.

Conclusions: Clinicians should be aware of the risk of severe OHSS and its possible effect on pregnancy outcomes beyond the first trimester.