Comparison of perinatal outcomes and pregnancy complications between fresh embryo transfer and frozen embryo transfer in singleton pregnant women

To compare perinatal outcomes and the incidence of pregnancy complications between fresh embryo transfer and frozen embryo transfer in singleton pregnant women.The clinical data of 3161 in vitro fertilization-embryo transfer cycles conducted in Center for Reproductive Medicine of the Third Affiliated Hospital of Sun Yat-sen University from October 2015 to May 2021 were retrospectively analyzed, among which 1009 cases were fresh embryo transfer (fresh embryo group) and 2152 cases were frozen embryo transfer (frozen embryo group). The baseline characteristics were compared between two groups, and logistic regression was used to analyze the effect of fresh embryo transfer and frozen embryo transfer on pregnancy outcome and complications.Compared with the fresh embryo group, the frozen embryo group had an increased gestational age (P<0.01), increased birth weight (P<0.01), higher cesarean section rate (65.1% vs. 50.7%, AOR=1.791, 95%CI: 1.421-2.256, P<0.01), higher risk of large for gestational age infant (12.7% vs. 9.4%, AOR=1.487, 95%CI: 1.072-2.064, P<0.05) and macrosomia (5.4% vs. 3.2%, AOR=2.126, 95%CI: 1.262-3.582, P<0.01). The incidences of early abortion (18.5% vs. 16.2%, AOR=1.377, 95%CI: 1.099-1.725, P<0.01) and gestational hypertension (3.1% vs. 1.9%, AOR=1.862, 95%CI: 1.055-3.285, P<0.05) in the frozen embryo group were significantly higher than those in the fresh embryo group. Stratified analyses by stage of embryo transfer showed that during blastocyst transfer, the gestational weeks of delivery, birth weight and risk of cesarean section in frozen embryo group were significantly higher than those in fresh embryo group. During cleavage stage embryo transfer, frozen embryo transfer was associated with a higher risk of cesarean section, macrosomia, miscarriage and early miscarriage, and the birth weight of newborns was also significantly increased.Compared with fresh embryo transfer, frozen embryo transfer is associated with a higher risk of abortion, early abortion, large for gestational age infant, macrosomia, cesarean section, and pregnancy induced hypertension. The birth weight of newborns after frozen embryo transfer is also significantly increased.目的: 对鲜胚移植与冻胚移植后单胎妊娠孕妇的妊娠结局及妊娠并发症进行比较，探讨不同胚胎移植方式的安全性和有效性。方法: 回顾性队列研究分析2015年10月至2021年5月在中山大学附属第三医院生殖医学中心首次接受体外受精-胚胎移植且单胎妊娠的3161名孕妇的资料，其中鲜胚移植1009名（鲜胚移植组）、冻胚移植2152名（冻胚移植组）。比较两组的基线特征，并采用logistic回归分析两种移植方案对妊娠结局及妊娠并发症的影响。结果: 与鲜胚移植组比较，冻胚移植组分娩孕周增加（P<0.01），新生儿出生体重增加（P<0.01），剖宫产率（65.1%与50.7%，AOR=1.791，95%CI：1.421~2.256，P<0.01）、大于胎龄儿（12.7%与9.4%，AOR=1.487，95%CI：1.072~2.064，P<0.05）和巨大儿（5.4%与3.2%，AOR=2.126，95%CI：1.262~3.582，P<0.01）的风险也有所增加。在妊娠并发症方面，冻胚移植组早期流产率（18.5%与16.2%，AOR=1.377，95%CI：1.099~1.725，P<0.01）、妊娠高血压（3.1%与1.9%，AOR=1.862，95%CI：1.055~3.285，P<0.05）的发生率高于鲜胚移植组。按照卵裂期和囊胚期进行分层分析，结果显示行囊胚移植时，冻胚移植较鲜胚移植后分娩孕周增加，新生儿出生体重增加，剖宫产风险显著增高；行卵裂期胚胎移植时，冻胚移植与较高的剖宫产、巨大儿、流产、早期流产风险相关，新生儿出生体重也显著增加。结论: 与鲜胚移植比较，冻胚移植与较高的流产率、早期流产、大于胎龄儿、巨大儿、剖宫产及妊娠高血压风险相关，冻胚移植后新生儿的出生体重也显著增加。.