Miscarriage Due To Endometriosis and Fibroids: What to Know

September 13, 2025

Miscarriage Due To Endometriosis and Fibroids: What to Know

Miscarriage is common, occurring in about 10% of clinically recognized pregnancies, most often in the first trimester. When you live with endometriosis or uterine fibroids, it’s natural to worry about how these conditions might affect your chances of a healthy pregnancy. Here’s what current evidence suggests, what factors matter most, and practical steps you can take with your care team.

Key takeaways

Endometriosis and fibroids are common conditions that can affect fertility and pregnancy.
Both have been associated with a higher risk of miscarriage in some studies, though not every person is affected and the degree of risk varies.
Fibroid size and location matter: fibroids that distort the uterine cavity (especially submucosal) are most linked to miscarriage.
Preconception evaluation and individualized treatment—such as removing cavity-distorting fibroids—may improve outcomes for some.
Early and close prenatal care can help identify complications and support a healthy pregnancy.

How common are endometriosis and fibroids?

Endometriosis affects an estimated 10% of reproductive-age women. It occurs when tissue similar to the uterine lining grows outside the uterus, causing inflammation and scarring. NIH/NICHD

Uterine fibroids (leiomyomas) are benign tumors of the uterine muscle. They’re very common—many women develop them during their reproductive years, and prevalence increases with age. Fibroids are more common and may be more severe among Black women. NIH/NICHD

Do endometriosis and fibroids cause miscarriage?

Not always. Many people with these conditions have healthy pregnancies. However, research suggests an association with higher miscarriage risk in some situations:

Endometriosis

Risk signal: Several studies and meta-analyses suggest women with endometriosis may have a modestly increased risk of early pregnancy loss compared with those without endometriosis, even after accounting for fertility treatments. Proposed mechanisms include inflammation, altered immune responses, and changes in how the uterine lining supports implantation. PubMed: Systematic review/meta-analysis
Heterogeneity matters: Severity and location of disease (e.g., ovarian endometriomas, deep infiltrating endometriosis) may influence risk, but findings are not entirely consistent across studies.

Fibroids

Location is key: Submucosal fibroids and intramural fibroids that distort the uterine cavity are most associated with miscarriage. Subserosal fibroids (on the outer surface of the uterus) generally have less impact on miscarriage risk. ACOG Patient FAQ
Possible mechanisms: Distortion of the uterine cavity can interfere with implantation and placentation, reduce blood flow to the developing pregnancy, or contribute to inflammation.

Important context: An association does not mean every pregnancy will be affected. Your individual risk depends on your age, obstetric history, other health conditions, specific disease characteristics, and whether you conceive spontaneously or with fertility treatment.

Symptoms and signs that warrant evaluation

Endometriosis: Pelvic pain, pain with periods or sex, painful bowel movements or urination (especially around menses), and infertility. NIH/NICHD
Fibroids: Heavy menstrual bleeding, pelvic pressure, frequent urination, constipation, pain, or infertility. NIH/NICHD

Preconception assessment: What your clinician might recommend

Detailed history and exam: Prior pregnancies, losses, cycle pattern, pain symptoms, and bleeding.
Pelvic imaging: Transvaginal ultrasound is first-line. Saline infusion sonohysterography or hysteroscopy can better assess whether fibroids distort the uterine cavity. MRI may be used for surgical planning.
Endometriosis evaluation: Diagnosis is often clinical and via imaging (e.g., endometriomas on ultrasound). Laparoscopy may be considered when diagnosis is uncertain or if surgery is planned for pain or fertility.
Screen and optimize overall health: Thyroid disease, diabetes, hypertension, and anemia can affect pregnancy outcomes. Address smoking, alcohol, and weight management; start a prenatal vitamin with folic acid.

Evidence-informed steps that may reduce miscarriage risk

For fibroids

Consider removing cavity-distorting fibroids: Hysteroscopic myomectomy (for submucosal fibroids) or myomectomy for select intramural fibroids that distort the cavity may improve fertility and reduce miscarriage risk in some patients. Decisions are individualized based on size, number, and location of fibroids, and your reproductive goals. ACOG
Medical therapies: Options such as GnRH analogs can shrink fibroids temporarily but are generally used short-term or before surgery; they are not long-term fertility solutions.

For endometriosis

Treat pain and plan timing: Hormonal therapies used for symptom control (e.g., combined hormonal contraceptives, progestins, GnRH analogs) prevent pregnancy and are typically paused before trying to conceive. Surgery to remove endometriotic lesions or endometriomas may be considered for pain relief or to improve fertility in selected cases; impacts on ovarian reserve should be discussed.
Assisted reproduction: If infertility coexists, your clinician may discuss intrauterine insemination or IVF based on your age, ovarian reserve, and disease severity.

During early pregnancy

Early prenatal care: Arrange an early visit and ultrasound to confirm location and viability, especially if you have significant fibroids or a history of miscarriage.
Medication review: Ensure all medications (including pain relievers and supplements) are pregnancy-safe.
Progesterone: In specific scenarios—such as early bleeding with a history of prior miscarriage—progesterone supplementation may be considered; discuss benefits and uncertainties with your obstetric clinician. ACOG
Aspirin: Low-dose aspirin is recommended for preeclampsia prevention in at-risk pregnancies, not routinely for miscarriage prevention unless you have conditions like antiphospholipid syndrome. ACOG

When to seek urgent care

Heavy bleeding (soaking through one pad per hour for more than two hours), passage of large clots, dizziness, or fainting.
Severe, worsening pelvic pain, shoulder pain, or pain on one side (could indicate ectopic pregnancy).
Fever, chills, or foul-smelling discharge.

Emotional health matters

Pregnancy loss is emotionally difficult, regardless of cause. Reach out to your clinician about counseling, support groups, or mental health resources. Grief support is part of comprehensive reproductive care.

Questions to ask your clinician

Do my fibroids or endometriosis change my miscarriage risk based on their size, number, or location?
Would imaging like saline sonohysterography or MRI help guide management before I try to conceive?
Could I benefit from fibroid removal or other interventions before pregnancy?
What monitoring or medications would you recommend in early pregnancy?
How do my age and overall health influence my plan?

Bottom line

Endometriosis and fibroids can be associated with a higher risk of miscarriage, particularly when fibroids distort the uterine cavity. Many people with these conditions still have successful pregnancies. A tailored plan—optimizing health, considering targeted procedures when indicated, and arranging early prenatal monitoring—can help improve your chances of a healthy outcome.