Vitrification can modify embryo cleavage stage after warming. Should we change endometrial preparation?

Abstract

Purpose Studies have shown that embryo metabolism and cell cleavage after warming vitrified embryos is faster than after thawing frozen embryos. We study vitrified embryo transfer (VET) results depending on the developmental stage of warmed embryos and the duration of progesterone treatment before embryo transfer. Methods We designed a prospective study, patients were randomized in two groups, starting progesterone three (D+ 3) or four days (D+4) before embryo transfer. We recruited 88 patients with embryos vitrified on day 3. Results We didn't find statitistical differences in pregnancy rate when we transferred embryos in D + 3 vs D + 4 (38.2 % vs 40.5 % p ≥ 0.05). The day after warming, 54.6 % of embryos had developed to morula or early blastocyst, 32.4 % to cleavage stage and 13 % didn't cleave. Transfers were with morula/blastocysts stage embryos (52.1 %; n:37), cleavage stage embryos (18.3 %; n:13) or mixed (29.6 %; n:21). Implantation rate was significantly higher in morula/blastocyst stage than in cleavage stage or mixed transfers (44 %, 22 % and 16.3 %; p00.011). Pregnancy and implantation rates were significantly higher in morula/blastocyst transfers on D+4 than on D+3 (68.7 % and 64.7 % vs 33.3 %, and 33.3 %, p00.033 and p00.034). Conclusions Our findings suggest that a majority of embryos will develop to morula/blastocyst stage after warming. VET results with morula/blastocysts, and after four days of progesterone supplementation, are better than with cleavage stage embryos.

Growth differentiation factor 9 and cumulus cell supplementation in in vitro maturation culture media enhances the viability of human blastocysts

“…Complete or relative disorder of microtubules was observed after cooling MII oocytes to room temperature or even lower. Poor embryonic development in a laboratory environment may be an important factor in reduced implantation, and consequently, in reduced pregnancy rates [26].…”

Preparation of endometrium for frozen embryo replacement cycles: a systematic review and meta-analysis

“…The type of freezing method, slow freezing versus vitrification, might have an impact on post-thaw embryo development and metabolism [75,76]. A higher post-thaw developmental rate of vitrified embryos might entail the need to change the endometrial preparation protocol, in particular the timing of progesterone commencement in artificial cycles, in order to obtain a better synchrony between embryos and endometrium.…”

Progesterone replacement with vaginal gel versus i.m. injection: cycle and pregnancy outcomes in IVF patients receiving vitrified blastocysts

“…Endometrial factors such as duration of progesterone before embryo transfer ( Nawroth and Ludwig, 2005 ), length of estrogen administration ( Nawroth and Ludwig, 2005 ) and lack of ovarian stimulation with gonadotrophins as in fresh IVF-embryo transfer ( Shapiro et al , 2008 ) may play a role. Embryonic factors, including the embryonic development stage at transfer and cryopreservation method, are also important ( Cercas et al , 2012 ). Several of these factors may play a role in the different pregnancy outcomes observed in our study compared with the study by Kaser et al (2012) .…”