Prevention of severe ovarian hyperstimulation by coasting

Abstract 

Objective: To evaluate the efficiency of withholding gonadotropins and deferring the administration of hCG until E₂ levels start dropping (coasting) in the prevention of ovarian hyperstimulation syndrome (OHSS) in a high-risk population.

Design: Retrospective case-control study.

Setting: In vitro fertilization program at a university center.

Patient(s): The case group consisted of 120 women undergoing ovarian stimulation for IVF who were considered to be at risk for ovarian hyperstimulation (serum E₂ levels >2,500 pg/mL or >20 follicles at the time of hCG administration).

Intervention(s): Gonadotropin administration was withheld when serum E₂ levels exceeded 2,500 pg/mL, and hCG administration was delayed until E₂ levels dropped below 2,500 pg/mL. Outcomes were compared with those from 120 matched patients in whom serum E₂ levels and the number of follicles at the time of hCG administration were comparable to those at the beginning of coasting (control group).

Main Outcome Measure(s): Incidence of moderate and severe OHSS. The number of oocytes retrieved and pregnancy rate (PR) were compared in both groups.

Result(s): Coasting decreased the incidence of moderate and severe OHSS. The odds ratio of severe OHSS in the coasting group was 0.11 (95% confidence interval 0.01–0.86). Although the number of oocytes was significantly lower in the coasting group (19.7 ± 0.6 versus 22.1 ± 0.6), coasting did not affect the PR (37.5% versus 36.7%).

Conclusion(s): Our study indicates that coasting is an efficient method for reducing the incidence and severity of OHSS without compromising the PR.

Keywords:  OHSS, coasting, IVF, gonadotropins, GnRH agonists