Obstetric outcome of women with in vitro fertilization pregnancies hospitalized for ovarian hyperstimulation syndrome: a case-control study.

Objective: To evaluate the obstetric outcome of women with IVF pregnancies hospitalized for ovarian hyperstimulation syndrome (OHSS).

Design: A case-control study.

Setting: Department of Obstetrics-Gynecology and Reproductive Medicine.

Patient(s): All IVF patients hospitalized for OHSS with a positive pregnancy test matched to an IVF pregnancy control group who did not develop OHSS.

Intervention(s): Retrospective study of all clinical and laboratory data.

Main Outcome Measure(s): OHSS morbidity, early pregnancy outcome, and obstetric complications.

Result(s): The incidence of OHSS requiring hospitalization was 1.14% among 3,504 IVF cycles. Forty patients (31 singletons, 8 twins, and 1 triplet) hospitalized for severe OHSS with a mean duration of hospitalization of 10.2 ± 7.2 days were compared with a control group of 80 IVF pregnancies (48 singletons, 15 twins, and 2 triplets). Early OHSS occurred in 22.5% of patients, and late OHSS in the remaining 77.5% patients. In the OHSS group, 10% had thromboembolic complications. The miscarriage rate was similar for the OHSS group and the control IVF group (17.5% vs. 16%). Concerning ongoing clinical pregnancies, pregnancy-induced hypertension (PIH) and preterm labor were significantly higher in the OHSS group (respectively, 21.2% vs. 9.2% and 36% vs. 10.7%). In the subgroup of singletons, PIH was significantly higher for OHSS pregnancies than for controls.

Conclusion(s): Pregnancies after IVF and OHSS are associated with a greater risk of adverse obstetric outcome.