European Journal of Obstetrics & Gynecology and Reproductive Biology
Vitrified-warmed embryo transfer is associated with mean higher singleton birth weight compared to fresh embryo transfer
Introduction
Cryopreservation of embryos or 2 PN oocytes and later transfer have become important tools in modern assisted reproductive techniques. During the last years, US and European registries report increasing numbers of babies delivered after cryopreservation of embryos [1], [2], [3]. Therefore, the evaluation of the safety of cryopreservation in terms of child health is utterly important.
A variety of freezing and thawing protocols have been reported in literature. Additionally, the type of cryopreserved tissue differs between countries as cryopreservation of embryos is not allowed everywhere. These facts highlight the difficulties in judging safety aspects of cryopreservation in literature as protocols differ from each other.
Several systematic reviews and cohort studies have indicated similar or even better neonatal outcomes for singletons born after cryopreservation compared to singletons born after fresh transfer [4], [5], [6], [7]. However, also higher rates of large for gestational age (LGA) and/or macrosomic infants were observed after cryo-transfer compared to singletons after spontaneous or fresh transfer. Of note, most studies have analyzed data on embryo cryopreservation and not 2PN oocyte cryopreservation [8], [9].
The aim of the present study therefore was to explore differences in birth weight of singleton deliveries after fresh embryo transfer and vitrified-warmed 2PN embryo transfer (vitrification protocol), respectively.
Section snippets
Materials and methods
The present study is a retrospective exploratory analysis based on data logged in the local IVF and labour ward software databases (Recdate Advance©; View Point® 6.0, GE Healthcare). The data were retrieved in January 2014. Approval from the Institutional Review Board was obtained before data collection, and the protocol was prospectively registered (NCT 01088425). The study included data on singleton deliveries after fresh embryo transfer in IVF or ICSI cycles and embryo transfer after
Results
In total, 464 singleton live births after IVF/ICSI met the inclusion criteria and were analyzed: 276 live births after fresh transfer (151 male/125 female) and 188 live births after vitrification transfer (106 male/82 female). Mean maternal age was 33.4 years with a SD of 4.1 years. Table 1 depicts an overview of baseline, treatment and outcome parameters in the two groups.
Discussion
Herein we show that vitrified-warmed 2PN embryo transfer is associated with mean higher birth weight for singletons compared to fresh embryo transfer. No association was found for the indication for ART treatment (male, female, idiopathic, both) and the sperm quality. Of note, in this cohort of singletons, the previously demonstrated association between number of embryos transferred and lower birth weight [13], [14], [15], [16] was also not confirmed. The difference in birth weight observed
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Cited by (8)
Antioxidant supplementation of mouse embryo culture or vitrification media support more in-vivo-like gene expression post-transfer
2022, Reproductive BioMedicine OnlineCitation Excerpt :The accumulation of in-vitro stresses has also been demonstrated with the cryopreservation of embryos (Truong and Gardner, 2020), whereby fetal and placental weights of transferred vitrified embryos cultured at atmospheric oxygen were lower than embryos cultured at 5%, thus highlighting the cumulative stress of culture at atmospheric oxygen and cryopreservation. While cryopreservation is largely seen as a safe and reliable procedure for the preservation of human gametes and embryos (Ozgur et al., 2015; Sekhon et al., 2018), there may be cryoinduced trauma to the embryo downstream (Barsky et al., 2016; Beyer and Griesinger, 2016; Maris et al., 2019; Pinborg et al., 2014; Spijkers et al., 2017). Exposure to high concentrations of cryoprotectants, osmolarities and rapid temperature changes during cryopreservation have been shown to affect gamete and embryo physiology (Dalcin et al., 2013; Fuller and Paynter, 2004; Gardner et al., 2007; Larman et al., 2007; Somoskoi et al., 2015) and their gene expression (Larman et al., 2011; Monzo et al., 2012; Sahraei et al., 2018; Stinshoff et al., 2011; Tachataki et al., 2003).
Birth weight and frozen embryo transfer: State of the art
2018, Gynecologie Obstetrique Fertilite et SenologieEffects of Rederivation by Embryo Vitrification on Performance in a Rabbit Paternal Line
2022, Frontiers in Animal ScienceFresh versus frozen embryo transfers in assisted reproduction
2021, Cochrane Database of Systematic ReviewsComparative neonatal outcomes of vitrified versus fresh embryo transfers: A systematic review and meta-analysis
2020, Reproductive and Developmental Medicine