Effect of Low Molecular Weight Heparin in Freeze-thaw Embryo Transfer Cycles in Women With Recurrent Implantation Failure

August 7, 2025 updated by: Linlin Cui, The Second Hospital of Shandong University
Recurrent implantation failure (RIF) is considered a tough problem in assisted reproductive technology (ART) without effective treatments. The effect of low molecular weight heparin (LMWH) in pregnancy outcomes is controversial. In addition, there are few reports on the role of LMWH in population with RIF performing freeze-thaw embryo transfer (FET) cycles. The purpose of this study is to evaluate the effect of LMWH on pregnancy outcomes in women with FET cycles.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
392

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shandong
      • Jinan, Shandong, China
        • The Second Hospital of Shandong University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study analyzed the data from the hospital electronic database for patients undergoing FET between January, 2021 and November, 2024, a total of 392 transplant cycles, who undergoing at least two IVF or ICSI cycles from the Second Hospital of Shandong University.

Description

Inclusion Criteria:

  • Women under or equal to the age of 40 when oocytes were retrieved;
  • The history of at least 2 failed fresh embryo transfer/FET cycles and cumulative transfer of ≥ 3 high-quality embryos or cumulative transfer of ≥ 2 blastocysts;
  • Planning to FET after IVF or ICSI cycles

Exclusion Criteria:

  • Women with untreated hydrosalpinx, uterine cavity occupying lesions (uterine adhesions, submucous fibroids, endometrial polyps, et al.);
  • Women with abnormal anatomical structure of uterus (unicornuate uterus, bipedal uterus, et al.);
  • Women with endometrial thickness (EMT) < 6mm on the day of transplantation;
  • Women or their partner with abnormal chromosome karyotype (not including chromosome polymorphisms);
  • Women with the history of recurrent spontaneous abortion (RSA);
  • Women with a history of autoimmune or coagulation disorders;
  • Women with contraindications to LMWH

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
LMWH group
the LMWH group received injections of 4100 IU/d LMWH from the day of transplant
Drug: Low Molecular Weight Heparine
the LMWH group received injections of 4100 IU/d LMWH from the day of transplant
Control group
the control group received the routine luteal support protocol (without LMWH use)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Ongoing pregnancy rate
Time Frame: from transplantation to delivery (assessed up to 40 weeks of gestation)
The number of ongoing pregnancies divided by the number of women who received a transfer
from transplantation to delivery (assessed up to 40 weeks of gestation)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
biochemical pregnancy rate
Time Frame: from transplantation to delivery (assessed up to 40 weeks of gestation)
The number of biochemical pregnancy cycles divided by the number of transplantation cycles
from transplantation to delivery (assessed up to 40 weeks of gestation)
clinical pregnancy rate
Time Frame: from transplantation to delivery (assessed up to 40 weeks of gestation)
The number of clinical pregnancies divided by the number of women who received a transfer
from transplantation to delivery (assessed up to 40 weeks of gestation)
ectopic pregnancy rate
Time Frame: from transplantation to delivery (assessed up to 40 weeks of gestation)
The number of ectopic pregnancies divided by the number of women who received a transfer
from transplantation to delivery (assessed up to 40 weeks of gestation)
Miscarriage rate
Time Frame: from transplantation to delivery (assessed up to 40 weeks of gestation)
The number of miscarriages divided by the number of clinical pregnancies
from transplantation to delivery (assessed up to 40 weeks of gestation)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The Second Hospital of Shandong University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 30, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 29, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 18, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 28, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 12, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 7, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • KYLL2025342

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The investigators fully acknowledge the significance of data sharing as stipulated by SCI journals. However, owing to the policies and confidentiality agreements adhered to in our laboratory, the investigators regretfully cannot furnish the raw data. Nevertheless, the investigators have meticulously presented a comprehensive account of the experimental design, analysis, results, and the procedures employed for data analysis and processing.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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