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Completed

NCT Number: NCT06991530

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

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.

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Key information

Conditions

Low Molecular Weight Heparin FET IVF Recurrent Implantation Failure

Age range

20 year–40 year

Sex eligibility

Female

Study type

Observational

Primary location

The Second Hospital of Shandong University

Jinan, Shandong, China

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Low Molecular Weight Heparine

Drug

the LMWH group received injections of 4100 IU/d LMWH from the day of transplant

Primary outcomes

  1. 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

Secondary outcomes

  1. 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

  2. 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

  3. 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

  4. 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

Sponsors and collaborators

Lead sponsor

The Second Hospital of Shandong University

Other

Registry information

Important dates

Study start
2021
Primary completion
2024
Study completion
2025
First posted
May 28, 2025
Registry last updated
Aug 12, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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