Journal of Assisted Reproduction and Genetics

, Volume 29, Issue 12, pp 1363-1368

First online:

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

  • R. CercasAffiliated withURH García del Real Email author 
  • , C. VillasAffiliated withURH García del Real
  • , I. PonsAffiliated withURH García del Real
  • , C. BrañaAffiliated withURH García del Real
  • , S. Fernandez-ShawAffiliated withURH García del Real

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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.


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.


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 %; p = 0.011). 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 %, p = 0.033 and p = 0.034).


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.


Vitrification Progesterone Endometrium Blastocyst Embryo cleavage Implantation window