OBJECTIVE: To evaluate, in a large cohort of patients, oocyte quality and IVF outcome after coasting used to prevent ovarian hyperstimulation. SETTING: Retrospective study. PATIENTS: IVF cycles which had reached estradiol serum levels of at least 4,000 pg/mL without being coasted (control group, n = 208), or where coasting was applied (coasted group, n = 157). METHOD: IVF data of coasted cycles were compared with the control group. Within the group of coasted cycles, we also analyzed whether indirect parameters related to coasting had an effect on IVF results. RESULTS: Coasted patients showed higher maximum estradiol levels and greater numbers of large follicles than the control group, but lower oocyte recovery rates. There were no other significant differences between the two groups of patients. Within the group of coasted patients, no significant relation was found between the number of days of coasting, the estradiol level on the day of hCG, or the fall in estradiol and the outcome, whether measured in terms of oocyte quality, pregnancy rate, or incidence of ovarian hyperstimulation. CONCLUSION: Coasting seems to be associated with a reduced oocyte collection rate, especially when the coasting period is prolonged. However, this does not result in reduced oocyte quality. The length of the coasting period and degree of estradiol decrease do not seem to alter the results in terms of pregnancy rates.
OBJECTIVE: To evaluate, in a large cohort of patients, oocyte quality and IVF outcome after coasting used to prevent ovarian hyperstimulation. SETTING: Retrospective study. PATIENTS: IVF cycles which had reached estradiol serum levels of at least 4,000 pg/mL without being coasted (control group, n = 208), or where coasting was applied (coasted group, n = 157). METHOD:IVF data of coasted cycles were compared with the control group. Within the group of coasted cycles, we also analyzed whether indirect parameters related to coasting had an effect on IVF results. RESULTS: Coasted patients showed higher maximum estradiol levels and greater numbers of large follicles than the control group, but lower oocyte recovery rates. There were no other significant differences between the two groups of patients. Within the group of coasted patients, no significant relation was found between the number of days of coasting, the estradiol level on the day of hCG, or the fall in estradiol and the outcome, whether measured in terms of oocyte quality, pregnancy rate, or incidence of ovarian hyperstimulation. CONCLUSION: Coasting seems to be associated with a reduced oocyte collection rate, especially when the coasting period is prolonged. However, this does not result in reduced oocyte quality. The length of the coasting period and degree of estradiol decrease do not seem to alter the results in terms of pregnancy rates.