Comparison of uterine peristalsis in artificial hormone treatment versus aromatase inhibitor-stimulated frozen embryo transfer cycles.

OBJECTIVE

Uterine peristalsis, which originates from sub-endometrial zone of myometrium, is observed at ultrasonography as a wave-like activity of endometrium. Increased uterine peristalsis is suggested to be related to decreased pregnancy rates in both fresh and frozen embryo transfer cycles. The aim of this study is to compare the effects of two different frozen embryo transfer preparation protocols on the frequency of uterine peristalsis and to evaluate the effect of peristalsis on pregnancy rates.

METHODS

In this observational cohort study, 3-min transvaginal ultrasound videos were recorded one hour before embryo transfer in frozen embryo transfer cycles prepared by either artificial hormone treatment or aromatase inhibitor stimulation. Peristalsis frequency was assessed by reviewing videos at triple speed. Consequent pregnancy outcomes were also analyzed.

RESULTS

During the study period of four months, a total of 147 patients with 99 artificial hormone treatments and 48 aromatase inhibitor-stimulated frozen embryo transfer cycles were included. The absence of uterine peristalsis was observed in 27.1% of the aromatase inhibitor-stimulated patients and 23.2% of the artificial hormone-treated patients (p = 0.68). Among those with peristalsis, the frequency was similar between groups (0.95 ± 0.59 and 0.98 ± 0.68 for the aromatase inhibitor-stimulated and artificial hormone treatment protocols, respectively; p = 0.97). Peristalsis presence or frequency was not associated with pregnancy or live birth rates.

CONCLUSIONS

In this study, uterine peristalsis frequency at frozen embryo transfer cycles did not differ between endometrial preparation protocols and showed no significant association with pregnancy outcomes. Further randomized studies are warranted.