The Impact of Myomectomy on IVF Outcomes: A Multicenter Randomized Controlled Trial (MIO)

May 5, 2026 updated by: Peking Union Medical College Hospital

Uterine fibroids are the most common benign tumors of the female reproductive system and are frequently encountered in women of reproductive age. Although many fibroids are asymptomatic, 5%-10% of women with infertility have coexisting fibroids, and in a small proportion fibroids may be the only identifiable cause of infertility. Fibroids may impair fertility by altering uterine anatomy, affecting uterine blood supply, inducing abnormal uterine contractions or endometrial peristalsis, and impairing endometrial receptivity.

The impact of fibroids on fertility depends strongly on their type, size, number, and relationship to the uterine cavity. Submucosal fibroids clearly reduce clinical pregnancy, implantation, and live birth rates and increase miscarriage risk in patients undergoing assisted reproductive technology. In contrast, the effect of intramural fibroids, especially those that do not distort the uterine cavity, remains controversial. Some studies suggest no significant effect on IVF outcomes, whereas others report reduced clinical pregnancy and live birth rates. Evidence also suggests that fibroids located close to the endometrium or measuring ≥4 cm may be more clinically relevant for assisted reproduction.

Current guidelines differ regarding whether infertile women with fibroids should undergo myomectomy before IVF. Chinese expert consensus recommends myomectomy for women preparing for pregnancy when fibroid diameter is ≥4 cm, whereas other international guidelines emphasize individualized management and note the lack of high-quality evidence. Existing studies are limited by small sample size, retrospective design, and inconsistent inclusion criteria. Therefore, whether myomectomy improves IVF outcomes in women with non-cavity-distorting intramural or subserosal fibroids remains uncertain.

Imaging plays an important role in fibroid assessment. Transvaginal ultrasound is widely used because it is inexpensive and accessible, but it has limitations in accurately localizing fibroids and detecting small lesions. Pelvic MRI provides more accurate evaluation of fibroid location, size, and relationship to the myometrium and endometrium, and is particularly useful for study eligibility assessment.

This multicenter randomized controlled trial is designed to evaluate whether myomectomy improves IVF outcomes in infertile women with FIGO type IV, V, or VI uterine fibroids measuring 4-6 cm. The study will compare IVF outcomes between women who undergo myomectomy before IVF and women who proceed directly to IVF without fibroid removal. The main objective is to determine whether surgical removal of these fibroids improves cumulative live birth after IVF.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

792

Phase

  • Not Applicable

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 20 years or older and younger than 40 years.
  • Primary infertility or secondary infertility. Infertility factors may include male partner factors, ovulatory disorders, tubal factors, endometriosis, other non-uterine corpus disease factors, or unexplained infertility.
  • Pelvic MRI indicating intramural fibroids: FIGO type 4-6; the largest fibroid has a maximum diameter of at least 4 cm and less than 6 cm; a total of no more than two fibroids measuring 4-6 cm; fibroids smaller than 4 cm may be disregarded.
  • Meets indications for IVF and is willing to undergo IVF treatment.

Exclusion Criteria:

  • Infertility factors related to diseases of the uterine corpus, including but not limited to adenomyosis, intrauterine adhesions, endometritis, submucosal fibroids, and multiple endometrial polyps. A single endometrial polyp 1 cm or smaller does not require exclusion.
  • Coexisting malignant or borderline tumors of the reproductive system, or other malignant tumors that are untreated or still under treatment.
  • Active pelvic inflammatory disease.
  • Previous cytotoxic therapy or pelvic/abdominal radiotherapy or chemotherapy.
  • Previous surgery of the uterine corpus, including but not limited to myomectomy, uterine wedge resection, uterine artery embolization, tumor coagulation of the uterine corpus such as high-intensity focused ultrasound or electrocoagulation, and hysteroscopic myomectomy. Prior hysteroscopy, diagnostic curettage, or hysteroscopic polypectomy does not require exclusion.
  • Expected inability to complete follow-up.

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: Intervention arm
This arm receives myomectomy before IVF.
Procedure: Myomectomy
Laparoscopic myomectomy is preferred. Abdominal myomectomy is also acceptable. In principle, layered closure with absorbable sutures should be used. If the full thickness of the myometrium is involved, closure should include at least two layers. Intraoperative tubal patency testing must be performed during surgery. If an endometrial polyp is present in a participant undergoing myomectomy, hysteroscopic endometrial polypectomy should be performed during the same operation.
No Intervention: Control arm
This arm receives IVF directly without surgical intervention for uterine myomas.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
cumulative live birth rate within 1 year after IVF treatment.
Time Frame: within 1 year after IVF treatment
number of participants with live birth / total number of participants who initiated treatment x 100%.
within 1 year after IVF treatment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical pregnancy rate after IVF
Time Frame: within 1 year of IVF
Visualization of an intrauterine gestational sac by transvaginal ultrasound after embryo transfer, with or without yolk sac, fetal heartbeat, or fetal pole. Calculation: number of clinical pregnancy cycles/number of embryo transfer cycles x 100%.
within 1 year of IVF
Biochemical pregnancy rate after IVF
Time Frame: within 1 year of IVF
a pregnancy state in which blood hCG is positive after embryo transfer but subsequently decreases, and no gestational sac is visualized by ultrasound. Calculation: number of biochemical pregnancy cycles / total number of cycles x 100%.
within 1 year of IVF
Ongoing pregnancy rate after IVF
Time Frame: within 1 year of IVF
Ongoing pregnancy is defined as an IVF pregnancy that progresses to 20 weeks of gestation or beyond. Calculation: number of pregnancy cycles with fetal heartbeat beyond 20 weeks / number of embryo transfer cycles x 100%.
within 1 year of IVF
Miscarriage rate after IVF
Time Frame: within 1 year of IVF
Miscarriage rate is defined as the proportion of pregnancy losses after clinical pregnancy. Calculation: number of miscarriages after clinical pregnancy / total number of clinical pregnancies x 100%.
within 1 year of IVF
Pregnancy-related complications
Time Frame: within 1 year of IVF
These include ectopic pregnancy, preterm birth, premature rupture of membranes, fetal distress, uterine rupture, fibroid degeneration during pregnancy, gestational diabetes mellitus, hypertensive disorders of pregnancy, and other relevant complications.
within 1 year of IVF

Collaborators and Investigators

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

Sponsor

Peking Union Medical College 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)

May 1, 2026

Primary Completion (Estimated)

June 1, 2028

Study Completion (Estimated)

June 1, 2029

Study Registration Dates

First Submitted

May 5, 2026

First Submitted That Met QC Criteria

May 5, 2026

First Posted (Actual)

May 11, 2026

Study Record Updates

Last Update Posted (Actual)

May 11, 2026

Last Update Submitted That Met QC Criteria

May 5, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • K4218

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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