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Plasma Relaxin Measurement Based on Endometrial Preparation for Embryo Transfer

NCT07477340 · Status: NOT_YET_RECRUITING · Type: OBSERVATIONAL · Enrollment: 60

Last updated 2026-03-17

No results posted yet for this study

Summary

Pregnancies achieved through assisted reproductive technology (ART) are associated with more obstetric complications than natural pregnancies.

In pregnancies achieved through in vitro fertilization, different obstetric outcomes are observed depending on the type of embryo transfer performed and the type of endometrial preparation. Studies comparing obstetric complications according to the type of transfer performed (fresh or frozen embryo transfer) suggest an increased risk of preeclampsia, fetal macrosomia, and postpartum hemorrhage in pregnancies achieved through frozen embryo transfer.

Depending on the endometrial preparation methods used prior to frozen embryo transfer, different obstetric risks are observed. Comparisons mainly focus on stimulated cycles versus natural cycles and spontaneous pregnancies. Pregnancies achieved through frozen embryo transfer in a stimulated cycle are thought to be at greater risk of preeclampsia, fetal macrosomia, and postpartum hemorrhage than natural cycles and spontaneous pregnancies. One of the first markers of this vascular adaptation is the cranio-caudal length (CCL).

Indeed, the cranio-caudal length of embryos in the first trimester is a good reflection of embryonic growth and therefore of vascular adaptation in the first trimester of pregnancy. Differences in growth between embryos from fresh transfers, frozen transfers, and spontaneous pregnancies are visible early on, as early as the first trimester.

The hypotheses put forward to explain these differences include the secretion of relaxin by the corpus luteum, which is present in the natural cycle but not in the substituted cycle. This hormone plays a role in cardiovascular and renal adaptation to pregnancy in the first trimester. Low levels of relaxin would therefore be associated with poorer cardiorenal adaptation in the first trimester and thus with greater vascular risks in late pregnancy.

Conditions

Interventions

BIOLOGICAL

Relaxine dosage

An additionnal 5m blood sample will be taken during the current blood sample at the beginning of the pregnancy.

Sponsors & Collaborators

  • Hospices Civils de Lyon

    lead OTHER

Eligibility

Min Age
18 Years
Max Age
45 Years
Sex
FEMALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2026-05-01
Primary Completion
2028-02-01
Completion
2028-02-01

Countries

  • France

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07477340 on ClinicalTrials.gov