Prediction of ovarian hyperstimulation syndrome in coasted patients in an IVF/ICSI program

To determine why a subgroup of coasted patients developed moderate/severe ovarian hyperstimulation syndrome (OHSS) in an assisted reproduction setting.

Retrospective study of 2948 in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment cycles with 327 patients requiring coasting. Long protocol gonadotrophin releasing hormone analogue (GnRH-a) regimen was used and serum estradiol (E(2)) checked when ≥20 follicles were noted on follicular tracking. Coasting was initiated when leading three follicles were ≥15mm with E(2) ≥1635pg/ml.

The incidence of moderate/severe OHSS was 10.4% in coasted patients (equivalent 1.15% of the total IVF/ICSI cycles in the Center). Coasted patients who subsequently developed OHSS showed a significantly higher number of retrieved oocytes, higher serum E(2) level on the day of human chorionic gonadotrophin (hCG) administration, and multiple pregnancies. No significant differences were noted with female age, BMI, cause of infertility, gonadotrophin dosage, coasting duration, and % of E(2) drop.

Moderate/severe OHSS might be predicted in coasted patients by a combination of total oocyte numbers and E(2) level on the day of hCG. Multiple pregnancies also significantly increased the risk.