The timing for initiating estrogen stimulation in artificial cycle for frozen-thawed embryo transfer can be flexible

Abstract

Background There remains a lack of evidence to demonstrate whether the initiation time of estrogen stimulation is flexible in the proliferative endometrial phase during the artificial cycle for frozen-thawed embryo transfer (AC-FET). Methods FET records were retrospectively reviewed from a large university-affiliated reproductive medicine center. Only the patients who were undergoing their first embryo transfer with a single blastocyst in the AC-FET cycles were included: thereby 660 cycles were recruited, and the patients were grouped according to their day of estrogen usage initiation as early initiation group (estrogen stimulation initiated during days 2–5 of menses, n = 128) and the late initiation group (estrogen stimulation initiated on or after the 6th day of menses, n = 532). The primary outcome was the ongoing pregnancy rates (OPR). Results The rates of biochemical and clinical pregnancies were significantly higher in the late initiation group relative to those in the early initiation group, however, no significant differences were noted between the two groups for OPR. Furthermore, after adjusting for the results of the potential confounders, no impact was observed in the initiation time of estrogen stimulation on the OPR. Conclusions This study provides evidence that initiating the estrogen stimulation on after days 2–5 of menses do not exert adverse effects on the OPR in AC-FETs. Thus, AC-FET can be scheduled in a flexible manner without compromising on the pregnancy outcomes.

Short (seven days) versus standard (fourteen days) oestrogen administration in a programmed frozen embryo transfer cycle: a retrospective cohort study

“…At present, few studies have addressed the effect of the number of days of continuous oestrogen administration on receiving autologous oocyte-derived frozen embryo transfer. Ying et al [ 24 ] found that biochemical and clinical pregnancy rates were significantly higher in the later oestrogen initiation group compared with the early oestrogen initiation group, however, ongoing pregnancy rates were not significantly different between groups. However, this study did not observe the effect of duration of oestrogen on live birth rate.…”

Short (seven days) versus standard (fourteen days) oestrogen administration in a programmed frozen embryo transfer cycle: a retrospective cohort study

“…At present, few studies have addressed the effect of the number of days of continuous oestrogen administration on receiving autologous oocyte-derived frozen embryo transfer. Ying et al 24 found that biochemical and clinical pregnancy rates were signi cantly higher in the later oestrogen initiation group compared with the early oestrogen initiation group, however, ongoing pregnancy rates were not signi cantly different between groups. However, this study did not observe the effect of duration of oestrogen on live birth rate.…”

Duration of oestrogen exposure does not affect reproductive outcome in artificial cycles: a retrospective analysis of more than 7000 hormonal replacement therapy cycles for an embryo transfer

“…Finally, the onset of oestrogen therapy (day 2-5 of cycle vs. day 6 onwards), and not its length, has been proven to have a significant impact on endometrial thickness, as well as on biochemical and clinical pregnancy, being higher in the late onset group. In contrast, the same relationship has not been proven for ongoing pregnancy rate ( 9 ).…”