Criteria of a successful coasting protocol for the prevention of severe ovarian hyperstimulation syndrome.

BACKGROUND: The aim of this study is to report a large series of patients (n = 1223) at risk of developing ovarian hyperstimulation syndrome (OHSS) who underwent coasting.

METHODS: Coasting started when the leading follicle reached 16 mm and continued until the estradiol (E2) level fell to 3000 pg/ml.

RESULTS: The E2 level at the start of coasting was (mean +/ SD) 6408 +/- 446 and it fell to 2755 +/- 650 on the day of HCG injection, after (mean +/- SD) 2.89 +/- 0.94 days. The results were analysed according to the duration of coasting (< or = 3 days, group I: n = 983; >3 days, group II: n = 240). The number of oocytes retrieved was (mean SD) 16.45 +/- 6.25 and 14.93 +/- 6.01 in groups I and II respectively (P < 0.05). The fertilization rates were 63 and 65% in groups I and II respectively (P > 0.05). The implantation and clinical pregnancy rates were 26 and 52% in group I compared to 18 and 36% in group II respectively (P < 0.05). Severe OHSS occurred in 16 cases, which represented 0.13% of all stimulated cycles, and 1.3% of patients who were at risk of developing OHSS.

CONCLUSIONS: Our protocol of coasting was an effective measure in the prevention of OHSS, without jeopardizing the ICSI outcome. Coasting for >3 days is associated with a moderate decrease in the pregnancy rate.