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 (E₂), and level of estradiol drop (E₂d) 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, E₂, and E₂d 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 E₂ or E₂d. 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 E₂, Cd, and E₂d, respectively.

Conclusion(s)

Although cycle numbers beyond 6 days are limited, coasting for up to 8 days does not affect LBR, and E₂ and E₂d levels do not significantly affect cycle outcome.

Key Words: Assisted reproduction, coasting, IVF/ICSI outcome, ovarian hyperstimulation