NCT04551807

Natural Versus Programmed Frozen Embryo Transfer (NatPro)

Multi-center, Parallel-group, Randomized Controlled Trial of Modified Natural Versus Programmed Cycles for Frozen Embryo Transfers and Their Association With Preeclampsia and Live Births

• Status: Active Not Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 788 (actual)
• Sponsor: JHSPH Center for Clinical Trials · Academic / Other
• Sex: Female
• Age: 18 Years – 41 Years
• Healthy volunteers: Accepted

Summary

NatPro is a two-arm, parallel-group, multi-center, randomized trial in which women undergoing frozen embryo transfer (FET) will be randomized to receive either a modified natural cycle (corpus luteum present) or a programmed cycle (corpus luteum absent).

Detailed description

NatPro is a two-arm, parallel-group, multi-center, randomized trial in which women undergoing FET will be randomized to receive either a modified natural cycle (corpus luteum present) or a programmed cycle (corpus luteum absent). The study will implement a stratified randomization design to balance the use of pre-implantation genetic testing (PGT) across the two treatment arms. Each participant will have up to 3 FET cycles until live birth occurs, or the participant has no embryos available for transfer. Primary endpoints will be the proportion of women experiencing preeclampsia comparing modified natural to programmed FET among women with viable pregnancy (defined as pregnancy lasting at least 20 weeks) and the cumulative proportion of women having live births in the two arms.

Conditions

• Pregnancy Related
• Pre-Eclampsia

Interventions

Type	Name	Description
PROCEDURE	Modified natural cycle	This treatment protocol is defined as a modified natural cycle as the participant will be instructed to (1) administer human chorionic gonadotropin (hCG) to assist with timing of the embryo transfer and (2) supplement the luteal phase with a low dose of progesterone.
PROCEDURE	Programmed cycle	This protocol is designated as programmed because the endometrial development occurs only in association with administration of estradiol and progesterone. No ovulation occurs due to suppression of follicle development by the estradiol and the timing of the transfer is based on the number of days elapsed following initiation of exogenous progesterone.

Timeline

• Start date: 2020-09-16
• Primary completion: 2026-02-01
• Completion: 2026-04-01
• First posted: 2020-09-16
• Last updated: 2025-05-16

Locations

15 sites across 1 country: United States