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Natural Versus Programmed Frozen Embryo Transfer (NatPro) | Clinical Trials | Clareo Health

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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

NCT04551807•JHSPH Center for Clinical Trials

View on ClinicalTrials.gov

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.

Eligibility

Age

18 - 41 years

Sex

FEMALE

Healthy Volunteers

Yes

Inclusion Criteria

•To be eligible, subjects must meet all these criteria:
•Age 18-39 years at the time that embryos were created if no PGT testing was performed. If PGT testing was performed and indicates that an embryo is euploid, the patient can be included if she was age 18-41 years at the time that the embryo was created.
•Age 18-41 years at the time of randomization as advancing age itself becomes a significant risk for preeclampsia
•Normal uterine cavity as assessed by saline infusion sonohysterogram, hysterosalpingogram, or hysteroscopy within one year of the enrollment visit, and repeated at the discretion of the investigator
•Regular menstrual cycle length (approximately 24-35 days) indicative of ovulatory cycles.
•Willing to undergo elective single embryo transfer
•Body Mass Index \<=40
•If Body Mass Index is over 30 or individual has other risk factors for diabetes, normal hemoglobin A1C
•Prior to enrollment, participant will have at least one vitrified blastocyst with euploid result by pre-implantation genetic testing (PGT-A) or at least one vitrified blastocyst of fair or better morphologic quality if no PGT-A results are available.
•Willingness to be randomized to either a modified natural or programmed cycle, with a willingness to administer intramuscular progesterone in oil if assigned to the programmed cycle.
+1 more criteria

Exclusion Criteria

•To be eligible, subjects must not meet any one of these criteria:
•Medical contraindication to pregnancy
•Embryos created using donor oocytes
•Embryo donation
•Gestational carrier
•Reciprocal IVF (one female partner carrying pregnancy, other female partner as source of eggs)
•Fresh embryos created from frozen oocytes. Patients with frozen embryos created from frozen oocytes can be included.
•Recurrent implantation failure defined as no clinical pregnancy with ≥ 2 prior consecutive embryo transfers unless patient also had successful live birth between or after the failed embryo transfers
•Anti-phospholipid antibody syndrome or rheumatologic disease requiring chronic systemic medications
•Uncontrolled diabetes mellitus
+6 more criteria

Locations (15)

University of California San Francisco

San Francisco, California, United States

Stanford University

Sunnyvale, California, United States

Yale

Orange, Connecticut, United States

Fertility Institute of Hawaii

Honolulu, Hawaii, United States

Northwestern University

Chicago, Illinois, United States

Johns Hopkins

Baltimore, Maryland, United States

Shady Grove Fertility

Rockville, Maryland, United States

Boston IVF

Waltham, Massachusetts, United States

University of Rochester

Rochester, New York, United States

Atrium Health

Charlotte, North Carolina, United States

Key Dates

Start Date

September 16, 2020

Primary Completion Date

February 1, 2026

Completion Date

April 1, 2026

Last Updated

May 16, 2025

Enrollment

788

ACTUAL participants

Conditions

Pregnancy RelatedPre-Eclampsia

Interventions

Modified natural cycle

PROCEDURE

Programmed cycle

PROCEDURE

Comparison of Two Salpingectomy Techniques for Sterilization at the Time of Cesarean Delivery

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Permanent SterilizationPregnancy Related

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RECRUITING

Odevixibat Pregnancy and Lactation Surveillance Program: A Study to Evaluate the Safety of Odevixibat During Pregnancy and/or Lactation

NCT06258902

Pregnancy Related

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Data Source & Attribution

This clinical trial information is sourced from ClinicalTrials.gov, a service of the U.S. National Institutes of Health.

ClinicalTrials.gov last update: May 16, 2025Data synced to Clareo: March 29, 2026

Modifications: This data has been reformatted for display purposes. Eligibility criteria have been parsed into inclusion/exclusion sections. Location data has been geocoded to enable distance-based search. For the authoritative and most current information, please visit ClinicalTrials.gov.

Neither the United States Government nor Clareo Health make any warranties regarding the data. Check ClinicalTrials.gov frequently for updates.

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Natural Versus Programmed Frozen Embryo Transfer (NatPro)

Inclusion Criteria

Exclusion Criteria

Comparison of Two Salpingectomy Techniques for Sterilization at the Time of Cesarean Delivery

Odevixibat Pregnancy and Lactation Surveillance Program: A Study to Evaluate the Safety of Odevixibat During Pregnancy and/or Lactation

Community-based Implementation of Adapted STAC

Dural Puncture Epidural vs Standard Epidural Analgesia in Labor

APPLE: Aspirin to Prevent Pregnancy Loss and Preeclampsia

Effects of Systematic Cervical Exam Training on Labor and Delivery Care