Intrauterine G-CSF Infusion for Thin Endometrium (GIFT)

July 8, 2026 updated by: Li-jun Ding, Nanjing University

A Single-Center Randomized Controlled Trial of Intrauterine G-CSF Infusion for Improving Pregnancy Outcomes in Patients With Thin Endometrium

Thin endometrium is a condition in which the lining of the uterus is too thin during preparation for embryo transfer. This may reduce the chance of pregnancy and live birth in patients undergoing frozen-thawed embryo transfer.

This study will evaluate whether intrauterine infusion of granulocyte colony-stimulating factor, also called G-CSF, can improve pregnancy outcomes in patients with thin endometrium. Participants will be randomly assigned to one of two groups. The experimental group will receive mild endometrial stimulation followed by intrauterine infusion of G-CSF 300 μg. The control group will receive the same mild endometrial stimulation followed by intrauterine infusion of normal saline. Both groups will then continue standard endometrial preparation for frozen-thawed embryo transfer.

The main outcome of the study is the live birth rate. The study will also assess endometrial thickness, endometrial blood flow, clinical pregnancy rate, miscarriage rate, and safety outcomes, including adverse events, pregnancy complications, fetal malformations, and neonatal birth defects. Participants will be followed from enrollment through embryo transfer, pregnancy assessment, and delivery.

This is a single-center, prospective, randomized controlled trial conducted at Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School. The planned sample size is 620 participants.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Thin endometrium remains a clinical challenge in assisted reproductive technology because it may reduce endometrial receptivity and the chance of successful embryo implantation and live birth. Several treatment strategies have been used for thin endometrium, including hormonal treatment, medications to improve blood flow, endometrial stimulation, and intrauterine infusion of granulocyte colony-stimulating factor (G-CSF). However, the clinical benefit of intrauterine G-CSF infusion remains uncertain, partly because previous studies have differed in patient populations, timing of administration, dose, and study design.

This study is designed to evaluate whether intrauterine infusion of G-CSF during the endometrial preparation phase can improve reproductive outcomes in patients with thin endometrium undergoing frozen-thawed embryo transfer. The study uses a prospective, single-center, randomized, parallel-group, blinded, superiority design. Eligible participants will be randomly assigned in a 1:1 ratio to receive either mild endometrial stimulation with intrauterine G-CSF infusion or mild endometrial stimulation with intrauterine normal saline infusion. Randomization will be performed using an interactive web response system.

All participants will receive routine endometrial preparation for frozen-thawed embryo transfer according to local clinical practice. In the intervention group, participants will undergo mild endometrial stimulation followed by intrauterine infusion of G-CSF 300 μg. In the control group, participants will undergo the same mild endometrial stimulation procedure followed by intrauterine infusion of an equal volume of normal saline. Participants, outcome assessors, and statistical analysts will be blinded to group assignment, while the physician performing the intrauterine procedure will not be blinded.

After the intrauterine procedure, endometrial development will be monitored by ultrasound. Embryo transfer will be performed after endometrial transformation according to the frozen-thawed embryo transfer protocol. Participants will be followed for pregnancy outcomes, delivery outcomes, and safety events. The study aims to determine whether the addition of intrauterine G-CSF to mild endometrial stimulation provides a clinically meaningful benefit compared with mild endometrial stimulation and saline control.

Study Type

Interventional

Enrollment (Estimated)

620

Phase

  • Phase 3

Contacts and Locations

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

Study Contact

Study Contact Backup

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Female patients aged 18 to <40 years.
  • Patients with normal ovarian function.
  • History of endometrial thickness ≤7 mm in at least one previous endometrial preparation cycle.
  • At least two good-quality embryos remaining.
  • Fewer than 3 previous embryo transfer cycles.
  • Willing and able to provide written informed consent.

Exclusion Criteria:

  • Uterine diseases or conditions that may affect the uterine cavity, including intramural uterine fibroids affecting the uterine cavity, severe adenomyosis, endometriosis, uterine malformation, endometrial tuberculosis, or severe untreated intrauterine adhesions.
  • Endometrial lesions, history of pelvic tumors, or previous radiotherapy or chemotherapy.
  • Known allergy to G-CSF.
  • Current participation in another clinical study.

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Mild Endometrial Stimulation With Intrauterine G-CSF Infusion
Participants in this arm will undergo mild endometrial stimulation followed by intrauterine infusion of G-CSF 300 μg during the endometrial preparation cycle for frozen-thawed embryo transfer.
Biological: Granulocyte Colony-Stimulating Factor(G-CSF)
Participants in the experimental arm will receive a single intrauterine infusion of G-CSF 300 μg after mild endometrial stimulation during the endometrial preparation cycle for frozen-thawed embryo transfer.
Other Names:
  • Recombinant Human Granulocyte Colony-Stimulating Factor
Placebo Comparator: Mild Endometrial Stimulation With Intrauterine Normal Saline Infusion
Participants in this arm will undergo the same mild endometrial stimulation procedure followed by intrauterine infusion of an equal volume of normal saline during the endometrial preparation cycle for frozen-thawed embryo transfer.
Drug: Normal Saline
Participants in the control arm will receive a single intrauterine infusion of an equal volume of normal saline after the same mild endometrial stimulation procedure during the endometrial preparation cycle for frozen-thawed embryo transfer.
Other Names:
  • Saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Live Birth Rate
Time Frame: From embryo transfer to delivery, approximately 40 weeks after embryo transfer
The proportion of participants who deliver at least one live-born infant after the registered frozen-thawed embryo transfer cycle. Live birth is defined as delivery of at least one newborn with signs of life at 28 weeks of gestation or later.
From embryo transfer to delivery, approximately 40 weeks after embryo transfer

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Endometrial Thickness
Time Frame: On the day 1 of endometrial transformation
Endometrial thickness will be measured by transvaginal ultrasound in the mid-sagittal plane of the uterus as the maximum double-layer endometrial thickness in millimeters.
On the day 1 of endometrial transformation
Endometrial and Sub-endometrial Blood Flow
Time Frame: On the day 1 of endometrial transformation
Endometrial and sub-endometrial blood flow will be assessed by transvaginal color Doppler or power Doppler ultrasound. Blood flow may be evaluated according to blood flow distribution type and/or three-dimensional Doppler indices, including vascularization index, flow index, and vascularization-flow index.
On the day 1 of endometrial transformation
Clinical Pregnancy Rate
Time Frame: 4 to 6 weeks after embryo transfer
The proportion of participants with an intrauterine gestational sac confirmed by transvaginal ultrasound after embryo transfer.
4 to 6 weeks after embryo transfer
Early Miscarriage Rate
Time Frame: From confirmation of clinical pregnancy to 12 weeks of gestation
The proportion of participants with clinical pregnancy who experience spontaneous pregnancy loss before 12 weeks of gestation.
From confirmation of clinical pregnancy to 12 weeks of gestation

Collaborators and Investigators

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

Sponsor

Nanjing University

Collaborators

The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School

Investigators

  • Principal Investigator: Yue Jiang, Nanjing Drum Tower Hospital: Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

August 1, 2029

Study Completion (Estimated)

August 1, 2029

Study Registration Dates

First Submitted

July 4, 2026

First Submitted That Met QC Criteria

July 8, 2026

First Posted (Actual)

July 9, 2026

Study Record Updates

Last Update Posted (Actual)

July 9, 2026

Last Update Submitted That Met QC Criteria

July 8, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-0087-04

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the study involves sensitive reproductive, pregnancy, delivery, and neonatal clinical information. The current study protocol and informed consent documents do not include a plan for public sharing of individual participant data. De-identified aggregate data may be reported in scientific publications.

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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