Burks Heather, Buckbinder Jennifer, Francis-Hernandez Mary, Chung Karine, Jabara Sami, Bendikson Kristin, Paulson Richard
Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Keck School of Medicine, University of Southern California, 2020 Zonal Avenue, Room 534, Los Angeles, CA, 90033, USA.
Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Kaiser Permanente, 4900 W. Sunset Boulevard, Los Angeles, CA, 90027, USA.
J Assist Reprod Genet. 2015 Oct;32(10):1477-81. doi: 10.1007/s10815-015-0561-8. Epub 2015 Sep 7.
In fresh IVF cycles, embryos reaching the eight-cell stage on day 3 of development are thought to have a higher chance of implantation than those reaching this stage on day 4. To determine whether this difference persists after cryopreservation, we compared pregnancy and implantation rates between frozen embryo transfer (FET) cycles using delayed cleavage-stage embryos (cryopreserved day 4) and normal cleavage-stage embryos (cryopreserved day 3).
Participants underwent FET between 2008 and 2012 using embryos cryopreserved on either day 3 (n = 76) or day 4 (n = 48), depending on the length of time needed to achieve the eight-cell stage. All embryos, regardless of day of cryopreservation, were thawed and transferred on the 4th day of vaginal progesterone following endometrial preparation with oral estradiol. Chi-square and Mann-Whitney U tests were used to compare patient demographics and cycle outcomes.
More women in the day 4 group had diminished ovarian reserve (44 vs 16 %, p = 0.003). Pregnancy outcomes in preceding fresh cycles were not different between the two groups. Pregnancy, implantation, and live birth rates following FET did not differ between the day 3 and day 4 groups.
This is the first study to address outcomes using day 3 versus day 4 cryopreserved embryos. Despite a higher prevalence of diminished ovarian reserve (DOR) in the day 4 group, delayed cleavage-stage embryos utilized in FET cycles performed as well as embryos growing at the normal rate, suggesting delayed embryo development does not affect embryo implantation as long as endometrial synchrony is maintained.
在新鲜的体外受精周期中，发育至第3天达到八细胞阶段的胚胎被认为比在第4天达到此阶段的胚胎具有更高的着床几率。为了确定这种差异在冷冻保存后是否仍然存在，我们比较了使用延迟卵裂期胚胎（第4天冷冻保存）和正常卵裂期胚胎（第3天冷冻保存）的冷冻胚胎移植（FET）周期之间的妊娠率和着床率。
2008年至2012年期间，参与者根据达到八细胞阶段所需的时间，使用在第3天（n = 76）或第4天（n = 48）冷冻保存的胚胎进行FET。所有胚胎，无论冷冻保存的日期如何，在口服雌二醇进行子宫内膜准备后，于阴道用黄体酮的第4天解冻并移植。使用卡方检验和曼-惠特尼U检验比较患者人口统计学和周期结局。
第4天组中卵巢储备功能减退的女性更多（44%对16%，p = 0.003）。两组之前新鲜周期的妊娠结局没有差异。FET后的妊娠率、着床率和活产率在第3天和第4天组之间没有差异。
这是第一项比较使用第3天与第4天冷冻保存胚胎结局的研究。尽管第4天组中卵巢储备功能减退（DOR）的患病率较高，但FET周期中使用的延迟卵裂期胚胎与正常发育速度的胚胎表现相同，这表明只要维持子宫内膜同步性，胚胎发育延迟并不影响胚胎着床。
