Şişmanoğlu Alper, Oğlak Süleyman Cemil, Özcan Cenk, Uluğ Ulun
Department of Obstetrics and Gynecology, Altınbaş University Faculty of Medicine, 34147 Istanbul, Türkiye.
Department of Obstetrics and Gynecology, Health Sciences University, Gazi Yaşargil Training and Research Hospital, 21500 Diyarbakır, Türkiye.
J Clin Med. 2025 Jun 28;14(13):4596. doi: 10.3390/jcm14134596.
Most studies concentrate on comparisons between the cleavage stage and blastocyst stage of embryos during in vitro stimulation treatment. We aimed, in this study, to compare the pregnancy rates of day 4 or day 5 blastocyst transfers, all derived from fresh, antagonist-regulated in vitro fertilization (IVF) cycles, and to evaluate the factors affecting pregnancy success. This retrospective cohort study evaluated 3681 fresh embryo transfer cycles conducted at a private IVF center between 2019 and 2021. Patients were divided into two groups based on the day of embryo transfer: day 4 (Group 1) and day 5 (Group 2). Subgroup analyses were performed according to age (≤40 vs. >40 years) and the number of oocytes retrieved (≤4 vs. >4). All patients underwent ovarian stimulation with FSH alone or in combination with hMG, and GnRH antagonist protocols were used for pituitary suppression. Final oocyte maturation was triggered with recombinant hCG, and fertilization was achieved via intracytoplasmic sperm injection (ICSI) for all cases. Embryos were cultured in sequential media and assessed daily until transfer on day 4 or day 5, based on embryo morphology and clinic logistics. Pregnancy was more likely among women under 40 than among women over 40. There were a total of 1217 women who underwent day 4 transfer and 2464 women who underwent day 5 transfer. A total of 660 (54.2%) of the women transferred on day 4 developed pregnancy. Among those transferred on day 5, 1610 (65.3%) developed pregnancy. When compared to the 4th day, a single embryo transfer on the 5th day enhances pregnancy success by 1.8 times, while two embryo transfers raise it by 1.6 times. Furthermore, when the number of oocytes is greater than four and the number of embryos transferred is two, the pregnancy success rate is 2.5 times higher when embryo transfer is performed on the fifth day versus the fourth day. Regardless of age, oocyte count, or number of embryos transferred, 5th-day fresh embryo transfers enhanced pregnancy success by 1.9 times compared to 4th-day transfer. Transfers of fresh embryos on day 5 are superior to those on day 4 and should be favored, especially for people over the age of 40, regardless of the number of embryos transferred, even if that individual has fewer than four oocytes.
大多数研究集中在体外刺激治疗期间胚胎的卵裂期和囊胚期之间的比较。在本研究中，我们旨在比较均来自新鲜的、拮抗剂调控的体外受精（IVF）周期的第4天或第5天囊胚移植的妊娠率，并评估影响妊娠成功的因素。这项回顾性队列研究评估了2019年至2021年在一家私立IVF中心进行的3681个新鲜胚胎移植周期。根据胚胎移植的日期将患者分为两组：第4天（第1组）和第5天（第2组）。根据年龄（≤40岁与>40岁）和获取的卵母细胞数量（≤4个与>4个）进行亚组分析。所有患者均接受单独使用FSH或与hMG联合的卵巢刺激，并使用GnRH拮抗剂方案进行垂体抑制。用重组hCG触发最终卵母细胞成熟，所有病例均通过卵胞浆内单精子注射（ICSI）实现受精。胚胎在序贯培养基中培养，并根据胚胎形态和临床安排每天进行评估，直到在第4天或第5天进行移植。40岁以下的女性比40岁以上的女性更有可能怀孕。共有1217名女性进行了第4天移植，2464名女性进行了第5天移植。在第4天进行移植的女性中，共有660名（54.2%）怀孕。在第5天进行移植的女性中，1610名（65.3%）怀孕。与第4天相比，第5天单胚胎移植的妊娠成功率提高了1.8倍，而双胚胎移植则提高了1.6倍。此外，当卵母细胞数量大于4个且移植的胚胎数量为2个时，第5天进行胚胎移植的妊娠成功率比第4天高2.5倍。无论年龄、卵母细胞数量或移植的胚胎数量如何，与第4天移植相比，第5天新鲜胚胎移植的妊娠成功率提高了1.9倍。第5天新鲜胚胎移植优于第4天，应优先选择，特别是对于40岁以上的人，无论移植的胚胎数量如何，即使该个体的卵母细胞少于4个。
