Effectiveness of two-step (consecutive) embryo transfer in patients who have two embryos on day 2: comparison with cleavage-stage embryo transfer.
OBJECTIVE
To evaluate the effectiveness, for patients who have only two embryos on day 2, of a two-step (consecutive) embryo transfer (ET) procedure in which a cleaved embryo is transferred on day 2 and a single blastocyst is transferred on day 5.


METHODS
Observational comparative study.


METHODS
Private IVF clinic.


METHODS
Ninety two-step ET cycles were performed in patients who had two embryos on day 2 (two-step group). Ninety day-2 ET cycles were performed in age- and infertility-matched patients who had two embryos on day 2 (control group).


METHODS
Cleaved-ET, extended culture of one embryo, and a second transfer of a blastocyst.


METHODS
Implantation and pregnancy rates.


RESULTS
The pregnancy and implantation rates in the two-step group (respectively 33.3% and 17.2%) were significantly higher than those in the control group (18.9% and 9.4%). Thirty-nine of the patients in the two-step group (43.3%) could not proceed to the second step of ET because no viable blastocyst could be obtained, but four of them conceived anyway.


CONCLUSIONS
Taking advantage of both day-2 ET and blastocyst transfer, two-step ET may be an effective option for ET in patients who have an insufficient number of embryos.
Goto
Sakae
S
Hanabusa Women's Clinic, Kobe, Hyogo, Japan. gotoms@tcn.zaq.ne.jp
Shiotani
Masahide
M
Kitagawa
Masaru
M
Kadowaki
Takashi
T
Noda
Yoichi
Y
D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000628:therapy*; D011247:Pregnancy; D018873:Pregnancy Rate; D013997:Time Factors