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

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.

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07499453

Acronym

SEQ-ET

Enrollment

778

Registered

2026-03-30

Start date

2014-01-01

Completion date

2024-09-01

Last updated

2026-03-30

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Infertility

Keywords

IVF, Sequential embryo transfer, Live birth rate

Brief summary

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.

Interventions

None listed

Study design

Observational model

CASE_CONTROL

Time perspective

RETROSPECTIVE

Eligibility

Sex/Gender

FEMALE

Age

20 Years to 42 Years

Healthy volunteers

Yes

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.

Design outcomes

Primary

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

Secondary

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

Countries

France

Outcome results