Revisiting natural cycle frozen embryo transfer: a systematic review and meta-analysis - PubMed
7 days ago
- #natural cycle
- #reproductive outcomes
- #frozen embryo transfer
- The study revisits natural cycle frozen embryo transfer (NC FET) as an alternative to hormone replacement therapy (HRT) for endometrial preparation.
- NC FET has regained attention due to potential improvements in maternal and perinatal outcomes, despite logistical challenges in monitoring and scheduling.
- A new protocol, natural proliferative phase (NPP) FET, combines physiological benefits with scheduling flexibility.
- The systematic review included 70 studies, evaluating true-NC, modified-NC, and NPP FET protocols.
- True-NC FET showed higher live birth rates (LBRs) in ovulatory cycles compared to those with luteinized unruptured follicles.
- Luteal phase support (LPS) with vaginal progesterone improved LBRs in true-NC FET but not in modified-NC FET.
- NPP FET demonstrated higher LBRs compared to HRT FET, suggesting potential benefits without compromising outcomes.
- Modified-NC FET allows scheduling flexibility with hCG administration across a follicle size range of 13-22 mm.
- The study highlights the need for high-quality trials to further validate findings, especially for NPP FET.