Impact of Sequential Double Embryo Transfer on Live Birth Rates: A Case-Control Study. (SEQ-ET)

A CASE-CONTROL OBSERVATIONAL STUDY ON THE IMPACT OF A SEQUENTIAL DOUBLE EMBRYO TRANSFER POLICY ON LIVE BIRTH RATES IN COUPLES UNDERGOING ASSISTED REPRODUCTIVE TECHNOLOGY.

The main aim of this study is to evaluate the impact and identify potential indications for sequential double embryo transfer (SEQ-ET) in couples undergoing assisted reproductive technology (ART). The study will compare live birth rates (LBR) between patients receiving SEQ-ET and those receiving standard double embryo transfer (DET), while assessing safety outcomes and potential indications, including endometrial immune under-activation. Each SEQ-ET case will be matched with a DET control based on age, transfer attempt rank, and ART technique. We hypothesize that SEQ-ET may enhance implantation in couples with previous ART failures without increasing the risk of complications, potentially through localized maternal-endometrial immune communication initiated by the initially transferred cleavage-stage embryos.

Study Overview

• Status: Completed
• Conditions: Infertility

• Study Type: Observational
• Enrollment (Actual): 778

Contacts and Locations

Study Locations

• France
  • Paris, France, 75012
    • Hôpital Pierre Rouquès - Les Bluets.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of couples undergoing assisted reproductive technology (ART) at Pierre Rouquès - Les Bluets Hospital between January 2014 and December 2023. Female participants are biologically capable of becoming pregnant and have undergone either sequential double embryo transfer (SEQ-ET) or standard double embryo transfer (DET). The population includes women with a history of previous ART attempts, and does not exclude participants based on the presence or absence of a specific disease or condition.

Description

Inclusion Criteria:

• Infertile patients undergoing IVF with planned SEQ-ET or DET.
• Age ≤ 42 years.

Exclusion Criteria:

• Age aged 43 years.
• Cycles in which only a single embryo was ultimately transferred and cycles in which no embryo transfer occurred.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Case group; Patients who underwent a SEQ-ET of one or two cleavage-stage embryos (day 2/3) followed by the transfer of a blastocyst-stage embryo (day 5/6) within the same cycle.
Control group; Patient who underwent a simultaneous DET defined as the transfer of two blastocyst-stage embryos (day 5 or day 6) in the same cycle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Live birth rate	LBR defined as delivery of a viable infant beyond 24 weeks of gestation, assessed after the first fresh or frozen blastocyst transfer.	From first embryo transfer to delivery (up to approximately 9 months).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical Pregnancy Rate	Clinical pregnancy confirmed by ultrasound visualization of a gestational sac.	6-8 weeks after embryo transfer.
Miscarriage Rate per Clinical Pregnancy	Pregnancy loss before 24 weeks of gestation among clinical pregnancies.	Up to 24 weeks of gestation.
Implantation Rate	Number of gestational sacs per number of embryos transferred.	6-8 weeks after embryo transfer.
Multiple pregnancies	Percentage of multiple pregnancies regardless of whether one or two day-2/3 are transferred before the day-5 embryo are transferred.	Up to 9 months

Collaborators and Investigators

• Sponsor: Hopital Pierre Rouques - Les Bluets

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2014
• Primary Completion (Actual): December 1, 2023
• Study Completion (Actual): September 1, 2024

Study Registration Dates

• First Submitted: March 24, 2026
• First Submitted That Met QC Criteria: March 24, 2026
• First Posted (Actual): March 30, 2026

Study Record Updates

• Last Update Posted (Actual): March 30, 2026
• Last Update Submitted That Met QC Criteria: March 24, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: IVF; Live birth rate; Sequential embryo transfer
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Infertility
• Other Study ID Numbers: SEQ-ET-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No