Natural vs. programmed cycles for frozen embryo transfer: study protocol for an investigator-initiated, randomized, controlled, multicenter clinical trial

Abstract

Background Randomized trials of assisted reproductive technology (ART) have been designed for outcomes of clinical pregnancy or live birth and have not been powered for obstetric outcomes such as preeclampsia, critical for maternal and fetal health. ART increasingly involves frozen embryo transfer (FET). Although there are advantages of FET, multiple studies have shown that risk of preeclampsia is increased with FET compared with fresh embryo transfer, and the reason for this difference is not clear. NatPro will compare the proportion of preeclampsia between two commonly used protocols for FET,modified natural and programmed cycle. Methods In this two-arm, parallel-group, multi-center randomized trial, NatPro will randomize 788 women to either modified natural or programmed FET and follow them for up to three FET cycles. Primary outcome will be the proportion of preeclampsia in women with a viable pregnancy assigned to a modified natural cycle FET (corpus luteum present) protocol compared to the proportion of preeclampsia in pregnant women assigned to a programmed FET (corpus luteum absent) protocol. Secondary outcomes will compare the proportion of live births and the proportion of preeclampsia with severe features between the protocols. Conclusion This study has a potential significant impact on millions of women who pursue ART to build their families. NatPro is designed to provide clinically relevant guidance to inform patients and clinicians regarding maternal risk with programmed and modified natural cycle FET protocols. This study will also provide accurate point estimates regarding the likelihood of live birth with programmed and modified natural cycle FET. Trial registration ClinicalTrials.govNCT04551807. Registered on September 16, 2020

Hormone replacement cycles are associated with a higher risk of hypertensive disorders: Retrospective cohort study in singleton and twin pregnancies

“…In twin pregnancies, the incidence of pre‐eclampsia was also higher. Prospective randomised controlled trials 35 are essential to clarify the potential mechanism underlying the influence of FET regimens with or without corpus luteum affecting pregnancy complications.…”

The value of ovarian hyperstimulation syndrome in predicting pregnancy outcome in women with polycystic ovarian syndrome and candidate for in vitro fertilization: A case-control study

“…After 10 days, ultrasound was performed and in the condition that the thickness of endometrial was at least 7 mm, trilaminar morphology and estradiol levels were at least 200 pg/mL the embryo transfer scheduled (19). Information about the treatment method, the amount of drugs used, age, BMI, cause of infertility, occurrence, and severity of OHSS, and the serum levels of AMH, FSH, LH, prolactin, estrogen, and both chemical and pregnancy rates were extracted from women's records in hospital and analyzed.…”