The effect of duration of coasting and estradiol drop on the outcome of assisted reproduction: 13 years of experience in 1,068 coasted cycles to prevent ovarian hyperstimulation

Objective: To determine the effect of duration of coasting (Cd), estradiol levels at trigger (E-2), and level of estradiol drop (E(2)d) on live birth rate (LBR) in cycle outcome. Design: Retrospective analysis. Setting: Hospital-based fertility clinic. Patient(s): A total of 1,068 coasted cycles (5.7% of total) of IVF/ICSI from 1996 to 2008. Intervention(s): Coasting in IVF/ICSI cycles. Main Outcome Measure(s): Live birth rate and secondary cycle outcomes. Result(s): Mean Cd, E-2, and E(2)d were 4.7 days, 11,567 pmol/L, and 9,760 pmol/L, respectively. Maternal age, duration of subfertility, and serum FSH were significantly lower, and AMH (39.7 vs. 15.1 pmol/L) and prevalence of polycystic ovary syndrome (31.8% vs. 17.8%) significantly higher, in coasted cycles. Fertilization rate, clinical pregnancy rate, and LBR per cycle and implantation rate of 64.4%, 40.7%, 35.7%, and 24.7%, respectively, were demonstrated, with no significant difference in LBR in cycles coasted for up to 8 days or when divided according to E-2 or E(2)d. Lack of predictive capability on LBR was confirmed by receiver operator curve analysis which demonstrated areas under the curve of 0.51, 0.53, and 0.54 for E-2, Cd, and E(2)d, respectively. Conclusion(s): Although cycle numbers beyond 6 days are limited, coasting for up to 8 days does not affect LBR, and E-2 and E(2)d levels do not significantly affect cycle outcome. (Fertil Steril (R) 2010;94:1757-63. (C)2010 by American Society for Reproductive Medicine.)