Department of Obstetrics and Gynecology, Turku University Hospital and University of Turku, Turku 20520, Finland.
Department of Obstetrics and Gynecology, Central Hospital of Central Finland, Jyväskylä 40620, Finland.
Reprod Biomed Online. 2021 Oct;43(4):607-613. doi: 10.1016/j.rbmo.2021.06.028. Epub 2021 Jul 15.
What are the pregnancy and perinatal outcomes of twice-cryopreserved embryos compared with embryos cryopreserved once?
Retrospective register-based case-control study. The case group consisted of transfers of twice-cryopreserved embryos (n = 89), and the control group of transfers of embryos cryopreserved once (n = 304). Matching criteria were embryonic age at transfer and female age category of less than 35 years or 35 and greater.
The survival rate of twice-cryopreserved embryos was 92.2%, and 93.7% of the planned frozen embryo transfers (FET) could be completed. FET was performed with cleavage-stage embryos in 17 cases and 68 controls and with blastocysts in 72 cases and 238 controls. The rates of live birth (27.0% versus 31.9%, adjusted odds ratio [OR] 0.70, 95% CI 0.40-1.22, P = 0.21), clinical pregnancy (31.5% versus 36.8%, adjusted OR 0.71, 95% CI 0.42-1.21, P = 0.21) and miscarriage (4.5% versus 3.9%, adjusted OR 1.10, 95% CI 0.33-3.60, P = 0.88) in the case and the control groups were comparable. No difference was seen in the preterm delivery rate (cases 4.2% versus controls 10.3%, P = 0.69). Twenty-five children were born in the case group and 100 in the control group. No difference in birthweight was detected between the groups and there were no large for gestational age fetuses or congenital malformations in the case group.
Uncompromised live birth rates and neonatal outcomes may be expected after the transfer of twice-cryopreserved embryos. To avoid embryo wastage and transfer of multiple embryos, good quality surplus embryos from FET cycles may be cryopreserved again by vitrification.
与单次冷冻胚胎相比，两次冷冻胚胎的妊娠和围产期结局如何？
回顾性基于登记的病例对照研究。病例组由两次冷冻胚胎移植（n=89）组成，对照组由单次冷冻胚胎移植（n=304）组成。匹配标准为胚胎移植时的胚胎龄和女性年龄小于 35 岁或 35 岁以上。
两次冷冻胚胎的存活率为 92.2%，计划的冷冻胚胎移植（FET）可完成 93.7%。17 例和 68 例对照组采用卵裂期胚胎进行 FET，72 例和 238 例对照组采用囊胚进行 FET。活产率（27.0%比 31.9%，调整后的优势比[OR]0.70，95%CI 0.40-1.22，P=0.21）、临床妊娠率（31.5%比 36.8%，调整后的 OR 0.71，95%CI 0.42-1.21，P=0.21）和流产率（4.5%比 3.9%，调整后的 OR 1.10，95%CI 0.33-3.60，P=0.88）在病例组和对照组之间无差异。早产率（病例组 4.2%比对照组 10.3%，P=0.69）无差异。病例组有 25 名儿童出生，对照组有 100 名儿童出生。两组间出生体重无差异，病例组无巨大儿和先天性畸形。
两次冷冻胚胎移植后，可获得较高的活产率和新生儿结局。为避免胚胎浪费和移植多个胚胎，可通过玻璃化法再次冷冻保存 FET 周期中优质的剩余胚胎。
