Low Molecular Weight HeparinNCT06991530
Effect of Low Molecular Weight Heparin in Freeze-thaw Embryo Transfer Cycles in Women With Recurrent Implantation Failure
An observational study of Low Molecular Weight Heparin and Recurrent Implantation Failure, run by The Second Hospital of Shandong University at 1 site in China.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 20 to 40 years, women only
- Conditions the study is for
- Low Molecular Weight Heparin, Recurrent Implantation Failure, FET
- What is being tested?
- Low Molecular Weight Heparine
- Type of treatment
- Injection or infusion
- How many people
- 392 participants
- Where
- 1 siteChina
- Study dates
- 1 Jan 2021to 1 Mar 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 40 years
- Women only
- No healthy volunteers
- Adult
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.
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
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.
- Conditions
- Low Molecular Weight Heparin, Recurrent Implantation Failure, FET, IVF
- Being tested
- Low Molecular Weight Heparine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low Molecular Weight HeparineDrug
the LMWH group received injections of 4100 IU/d LMWH from the day of transplant
| Study group | Role | What they receive |
|---|---|---|
| LMWH group | the LMWH group received injections of 4100 IU/d LMWH from the day of transplant Receives: Drug: Low Molecular Weight Heparine | |
| Control group | the control group received the routine luteal support protocol (without LMWH use) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ongoing pregnancy rate
The number of ongoing pregnancies divided by the number of women who received a transfer
Measured: from transplantation to delivery (assessed up to 40 weeks of gestation)
Secondary outcomes (4)
biochemical pregnancy rate
The number of biochemical pregnancy cycles divided by the number of transplantation cycles
Measured: from transplantation to delivery (assessed up to 40 weeks of gestation)
clinical pregnancy rate
The number of clinical pregnancies divided by the number of women who received a transfer
Measured: from transplantation to delivery (assessed up to 40 weeks of gestation)
ectopic pregnancy rate
The number of ectopic pregnancies divided by the number of women who received a transfer
Measured: from transplantation to delivery (assessed up to 40 weeks of gestation)
Miscarriage rate
The number of miscarriages divided by the number of clinical pregnancies
Measured: from transplantation to delivery (assessed up to 40 weeks of gestation)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 May 2025
- Study start1 Jan 2021
- Primary completion30 Nov 2024
- Study completion1 Mar 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Low Molecular Weight HeparinStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 392 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Second Hospital of Shandong University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Linlin Cui, The Second Hospital of Shandong University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06991530
- Sponsor's protocol ID
- KYLL2025342
- Status last verified
- Aug 2025
- First submitted
- 29 Apr 2025
- Last updated
- 12 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Low Molecular Weight Heparin in Freeze-thaw Embryo Transfer Cycles in Women With Recurrent Implantation Failure
- ClinicalTrials.gov ID
- NCT06991530
- Acronym / sponsor ID
- KYLL2025342
- Conditions
- Low Molecular Weight Heparin, Recurrent Implantation Failure, FET, IVF
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 392 participants (actual)
- Lead sponsor
- The Second Hospital of Shandong UniversityUniversity, hospital or other
- Study start
- 1 Jan 2021 (actual)
- Primary completion
- 30 Nov 2024 (actual)
- Study completion
- 1 Mar 2025 (actual)
- First posted
- 28 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| LMWH group | – | Drug: Low Molecular Weight Heparinethe 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) |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- 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.
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (7 listed)
- 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);
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low Molecular Weight Heparinethe LMWH group received injections of 4100 IU/d LMWH from the day of transplant | Drug | LMWH group |
Primary outcome
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
4 secondary outcomes
biochemical pregnancy rate
Time frame: 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)
ectopic pregnancy rate
Time frame: 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)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Aug 2025.
- Individual participant dataSharing planned: No. 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.
Related trials for Low Molecular Weight Heparin
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Enrolling by invitationPhase 4
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RecruitingPhase 3
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Low Molecular Weight Heparin and Recurrent Implantation Failure, run by The Second Hospital of Shandong University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ongoing pregnancy rate (time frame: from transplantation to delivery (assessed up to 40 weeks of gestation)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Aug 2025.