Length of ovarian stimulation does not impact live birth rate in fresh donor oocyte cycles: a SART CORS study

Purpose: To evaluate the effect of controlled ovarian hyperstimulation length and total gonadotropin (GN) dose on recipient live birth rate (LBR) in fresh donor oocyte cycles. Methods: Data was obtained from SART CORS on all fresh donor oocyte GnRH antagonist cycles (n = 1049) between 2014 and 2015 which resulted in a single embryo transferred. Donor and recipient demographic information and cycle characteristics were extracted. Binomial regression was used to estimate LBR with respect to days of stimulation (DOS) and total GN dose. Multivariate analysis was performed to evaluate these relationships after controlling for confounders. Results: Overall LBR in fresh donor oocyte cycles was 57%. Average stimulation length was 14.3 ± 4.9 days, and total GN dose was 2464 ± 1062 IU. On univariate analysis, neither days of stimulation (p = 0.5) nor total GN dose (p = 0.57) was independently correlated with LBR. However, in prolonged stimulations (> 15 days) with high total GN dose (> 3000 IU), as both the cycle length and total GN dose increased, LBR significantly decreased from 63.81 to 48.15% (p = 0.02) and from 67.61 to 48.15% (p = 0.01), respectively. Multivariate analysis showed no significant effect of either DOS or total GN dose on LBR. Conclusions: LBR is significantly decreased in fresh donor oocyte cycles when cycles are prolonged with high total GN dose. However, after controlling for confounders neither DOS nor total GN dose significantly affects LBR.