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.