Fresh versus Frozen Embryo Transfer in PCOS: Arguments for and Against

Abstract

In vitro fertilization (IVF) is a common infertility treatment for women with polycystic ovarian syndrome (PCOS) who have failed to conceive in ovulation induction and who have other concomitant infertility factors. Women with PCOS tend to have an excess response to ovarian stimulation during IVF. Freeze-all strategy with deferred frozen embryo transfer was initially used to prevent ovarian hyperstimulation syndrome (OHSS) in patients with a high risk. New evidence from randomized trials showed elective frozen embryo transfer in PCOS women with a low risk of OHSS could also lower the incidence of OHSS, improve live birth rate mainly by decreasing pregnancy loss, and increase birth weight of singleton infants compared with fresh embryo transfer. However, the risk of preeclampsia was higher after frozen than fresh embryo transfer. Observational studies and limited randomized trials showed the risks of other obstetric outcomes and long-term safety profile after frozen embryo transfers were at least as good as that after fresh embryo transfer. Summarily, current evidence showed elective freeze-all and frozen embryo transfer is generally superior to fresh embryo transfer to achieve live birth in women with PCOS; however, its effect on obstetric outcome and long-term outcome warrants further studies.

Systematic review update and meta-analysis of randomized and non-randomized controlled trials of ovarian stimulation versus artificial cycle for endometrial preparation prior to frozen embryo transfer in women with polycystic ovary syndrome

“…The early-onset of OHSS is related to exaggerated ovarian response to gonadotrophin stimulation and administration of hCG, while the late-onset is related to the endogenous hCG from trophoblast where conception occurs [ 5 ]. To prevent OHSS, freezing all embryos and waiting for a suitable time for embryo transfer are proposed [ 6 ]. Indeed, a randomized clinical trial with a large sample size showed that women with PCOS who underwent frozen-embryo transfer (FET) had a lower incidence of OHSS (1.3% vs. 7.1%) and pregnancy loss (22% vs. 32.7%) and a higher rate of live birth (49.3% vs. 42%), compared with women with PCOS underwent fresh embryo transfer cycles [ 7 ].…”

“…Indeed, a randomized clinical trial with a large sample size showed that women with PCOS who underwent frozen-embryo transfer (FET) had a lower incidence of OHSS (1.3% vs. 7.1%) and pregnancy loss (22% vs. 32.7%) and a higher rate of live birth (49.3% vs. 42%), compared with women with PCOS underwent fresh embryo transfer cycles [ 7 ]. To achieve a better pregnancy outcome, selective FET is considered a cost-effective treatment for those infertile women with PCOS in many IVF centers [ 6 , 8 ].…”

Non-invasive Prenatal Testing in Pregnancies Following Assisted Reproduction

“…Fresh ART cycles involve controlled ovarian stimulation, usually with high doses of gonadotrophin, to obtain multifollicular growth, but this, in turn, is linked to supraphysiological levels of estradiol and increased risk of ovarian hyperstimulation (OHSS) [ 84 ]. Consequently, all over the world, there is an increasing trend towards ‘freeze all’ cycles in ART practice [ 85 , 86 ], and a higher number of frozen embryo transfers are being performed to avoid the risk of OHSS and for endometrial optimization in subsequent cycles leading to oocyte retrieval. This might, to an extent, help to mitigate the burden of test failures and diagnostic errors due to low FF in the setting of ART.…”

Association of infertility cause with perinatal outcomes in a freeze-all policy: an analysis including 10,151 singleton newborns

“… 10 , 22 As opposed to fresh cycles, frozen-thawed embryo transfer (FET) appears to provide a better and more physiological uterine environment for early implantation and fetal development. 23 , 24 In the context of the increasing adoption of FET globally, additional data would be more than welcome to explore whether the type of infertility cause may have any significant influence on birth outcomes resulting from FET cycles. The objective of this study was therefore to investigate the effect of infertility cause on perinatal outcomes when a freeze-all strategy was applied from a single center.…”