Reproductive System & Sexual Disorders: Current Research
Open Access

Abstract

Is the freeze-all strategy for all?

Matheus Roque, Marcello Valle and Selmo Geber

In the past few years, the freeze-all strategy has emerged as an alternative to fresh embryo transfer (ET) during in vitro fertilization (IVF) cycles. Although fresh ET is the norm during assisted reproductive therapies (ART), there are many concerns about the possible adverse effects of controlled ovarian stimulation (COS) over the endometrium. COS is necessary to the development and maturation of many follicles and oocytes, therefore, it increases the chance of positive outcomes and cumulative pregnancy rates during ART. However, the supra-physiologic hormonal levels that occur during a conventional COS are associated with modifications in the peri-implantation endometrium that may be related to decrease in pregnancy rates, and poorer obstetric and perinatal outcomes when comparing fresh to frozen-thawed embryo transfers.