Natural Ovulation Regimens for Frozen Embryo Transfer: Equivalent Efficacy with Enhanced Maternal Safety

Introduction

In the rapidly evolving landscape of assisted reproductive technology (ART), frozen embryo transfer (FET) has become a cornerstone of clinical practice. The strategy of freezing all embryos to avoid ovarian hyperstimulation syndrome (OHSS) or to allow for preimplantation genetic testing has shifted the focus toward optimizing endometrial preparation. Historically, clinicians have balanced two primary approaches: the natural ovulation regimen, which relies on the patient’s endogenous hormonal milieu, and the programmed regimen, which uses exogenous estrogen and progesterone to prepare the uterus. While both methods are widely utilized, emerging evidence has suggested that the hormonal environment at the time of implantation may have profound implications for obstetric and neonatal outcomes.

Highlights