Correctly timed coasting reduces the risk of ovarian hyperstimulation syndrome and gives good cycle outcome in an in vitro fertilization program

One hundred and twelve severely overstimulated in vitro fertilization /intr acytoplasmic sperm injection (IVF/ICSI) patients were treated with coasting when estradiol concentration was > 3000 pg/ml and the leading follicles ha d attained greater than or equal to 18 mm in diameter. Gonadotropin withhol ding war offered to them as a promising method for the prevention of both c ycle cancellation and complications associated with severe ovarian hypersti mulation syndrome (OHSS). The duration of prolonged coasting prior to human chorionic gonadotropin (hCG) administration ranged from 2 to 9 days (mean 3.5). hCG was administered when the serum estradiol dropped to < 3000 pg/ml and at least three growing follicles greater than or equal to 20 mm in dia meter were present. Fertilization failure was noted in six couples and in a nother 10 cases freezing of all embryos was decided, therefore embryo trans fer was performed on 96 patients. There were 31 clinical pregnancies (five twins) giving a pregnancy rate per patient and per embryo transfer of 30.4% and 32.3%, respectively, with an implantation rate of 18.1%. With regard t o all 112 coasted patients, six developed moderate and two severe OHSS. Thi s study shows that withholding gonadotropin administration in high-risk IVF patients results in a good cycle outcome and a very low risk of severe OHS S, and also demonstrates the importance of both the timing of coasting init iation and the timing of hCG administration.