The Effect of Freezing Twice during Assisted Reproductive Technology on Perinatal and Neonatal Outcomes

Abstract

Objective. The aim of this paper was to investigate whether two freeze-thaw cycles before embryo transfer may affect perinatal and neonatal outcomes. Materials and Methods. A total of 8,028 frozen-thawed embryo transfer patients who became pregnant between March 2013 and September 2019 were included. The patients were divided into two groups: the oocyte cryopreservation (OC) group ( N = 96 ) and the control group ( N = 7932 ). Propensity score matching (PSM) was used to adjust the baseline characteristics of the two groups at a proportion of 1 : 4. There were 96 patients in the OC group and 369 patients in the control group after PSM. The pregnancy-related complications and neonatal conditions after delivery of the two groups were compared. Results. The OC group had a higher stillbirth rate (3.1% vs. 0.3%, P = 0.029 ) than the control group after PSM. Moreover, a slightly higher pregnancy defect rate was found in the OC group. There was no significant difference in the rates of diabetes mellitus, hypertension during pregnancy, cesarean section, multiple births, low birth weight (LBW), or premature birth defects between the two groups. Conclusions. Our findings demonstrate that performing frozen-thawed embryo transfer (FET) with cryopreserved oocytes was associated with a higher rate of stillbirth than FET with fresh oocytes. The incidences of diabetes, gestational hypertension, cesarean section, multiple births, LBW, premature birth, and birth defects of the two groups were not significantly different.

Risk of genetic and epigenetic alteration in children conceived following ART: Is it time to return to nature whenever possible?

“…It has been shown that DMSO and EG can induce alterations in DNA methylation and structural changes in the chromatin and DNA double‐strand breaks 86 . These cryoprotectants might affect embryo metabolism, such as protein expression, DNA integrity, and cytoskeletal and nuclear structures 87–90 . A few studies have suggested that CPAs might be linked to epigenetic aberration in oocytes and embryos, and these alterations could be transmitted to future generations 91,92 .…”

“…86 These cryoprotectants might affect embryo metabolism, such as protein expression, DNA integrity, and cytoskeletal and nuclear structures. [87][88][89][90] A few studies have suggested that CPAs might be linked to epigenetic aberration in oocytes and embryos, and these alterations could be transmitted to future generations. 91,92 Thus, since cryopreservation has become widely used in ART and other fields such as regenerative and transplantation medicine, it is critical to examine potentially genomic and epigenetic changes associated with the current technique.…”