Uterine Fibroids: Common Comorbidities, Overlap Conditions, and What Treatment Actually Looks Like

What Are Uterine Fibroids and Why Do They Matter for Women Specifically?

Uterine fibroids, clinically called leiomyomas, are benign smooth-muscle tumors that grow in or around the uterine wall. They are the most common gynecologic tumor in women of reproductive age. Studies across multiple cohorts place lifetime prevalence at 70 to 80 percent by age 50, with wide variation by race, hormonal status, and genetic background.

Black women carry a disproportionate burden. They are two to three times more likely to develop fibroids than white women, develop them roughly a decade earlier, and experience larger and more numerous tumors at diagnosis. A 2013 study in the American Journal of Obstetrics and Gynecology confirmed that by age 35, fibroids had been detected in approximately 60 percent of Black women versus 40 percent of white women.

Fibroids are classified by location. Submucosal fibroids project into the uterine cavity and most directly impair fertility and cause heavy bleeding. Intramural fibroids sit within the muscular wall. Subserosal fibroids grow outward and often cause bulk symptoms such as pelvic pressure, urinary frequency, and constipation.

How Estrogen and Progesterone Drive Fibroid Growth

Fibroids are hormonally sensitive. Both estrogen and progesterone stimulate growth, which is why they enlarge during pregnancy and shrink after menopause. Research published in the Journal of Clinical Endocrinology and Metabolism showed that progesterone receptor expression is upregulated in fibroid tissue compared to normal myometrium, explaining why progesterone-only contraception does not reliably shrink fibroids and can sometimes maintain their size.

This hormonal dependence is central to treatment design. It also means that any condition altering your hormonal milieu, including PCOS, perimenopause, and thyroid dysfunction, can change fibroid behavior.

Common Comorbidities: What Conditions Frequently Overlap With Fibroids?

Fibroids rarely occur in isolation. Several gynecologic and systemic conditions share risk factors, mechanisms, or symptoms with leiomyomas, and distinguishing between them is clinically consequential.

Endometriosis

Endometriosis and fibroids are both estrogen-dependent conditions, and they co-occur more often than chance would predict. A 2020 meta-analysis in Fertility and Sterility found that women with endometriosis had a significantly elevated odds of also having uterine fibroids (OR 1.49, 95% CI 1.02 to 2.17). Both conditions cause dysmenorrhea and subfertility, and both are underdiagnosed, which is why a woman reporting pelvic pain with heavy bleeding should be evaluated for both simultaneously.

The challenge is that ultrasound reliably detects fibroids but misses most superficial endometriosis. If your symptoms include deep dyspareunia or pain outside of menses, mention this explicitly to your clinician so MRI or diagnostic laparoscopy enters the conversation.

Adenomyosis

Adenomyosis, where endometrial glands invade the uterine muscle, mimics fibroids in almost every symptomatic way: heavy bleeding, dysmenorrhea, and an enlarged, boggy uterus. ACOG acknowledges that adenomyosis and fibroids coexist in a substantial proportion of women undergoing hysterectomy, with some series reporting concurrent findings in 15 to 57 percent of specimens. Distinguishing between them on imaging matters because adenomyosis does not respond to fibroid-targeted medical therapy in the same way.

PCOS and Hormonal Overlap

Polycystic ovary syndrome drives chronically elevated estrogen relative to progesterone through anovulatory cycles. That unopposed estrogen exposure may promote fibroid growth, though direct causal data are limited. What is clear is that women with PCOS and fibroids often present with compounding menstrual dysfunction: irregular cycles from PCOS layered onto heavy bleeding from fibroids makes cycle tracking and treatment planning more complicated.

If you have PCOS and are considering hormonal therapy to regulate cycles, your clinician should confirm fibroid status first, since high-dose estrogen-containing preparations could theoretically stimulate fibroid growth.

Iron-Deficiency Anemia

This is the most clinically immediate comorbidity. Heavy menstrual bleeding from fibroids is one of the leading causes of iron-deficiency anemia in premenopausal women worldwide. The American Society of Hematology notes that up to 63 percent of women with symptomatic fibroids have iron deficiency, with a significant subset reaching frank anemia. Symptoms of anemia, including fatigue, brain fog, and exertional breathlessness, are often attributed to other causes before the fibroid-bleeding-anemia chain is identified.

Treating the anemia without addressing the fibroid simply buys time. Ask your clinician to measure both ferritin and hemoglobin, not just hemoglobin alone, since iron stores deplete before hemoglobin falls.

Hypertension and Metabolic Conditions

A prospective analysis published in Epidemiology found that hypertension was associated with a 24 percent increased risk of uterine fibroid diagnosis. The mechanism is not fully established, but shared inflammatory pathways and insulin resistance appear to play a role. Obesity also independently increases fibroid risk, likely through elevated circulating estrogen from adipose aromatization.

Women managing both fibroids and cardiometabolic conditions should know that certain fibroid treatments, particularly GnRH agonists used to shrink fibroids preoperatively, can raise LDL cholesterol and should be used with awareness of cardiovascular risk.

Thyroid Dysfunction

Thyroid disorders are common in women of reproductive age, and hypothyroidism independently causes heavy menstrual bleeding by altering coagulation factors and prolonging the follicular phase. When heavy bleeding is present, thyroid-stimulating hormone (TSH) should be checked to ensure hypothyroidism is not compounding fibroid-related blood loss. The American Thyroid Association recommends TSH screening in symptomatic women, and treating subclinical hypothyroidism can meaningfully reduce menstrual blood volume even when fibroids remain present.

How Uterine Fibroids Are Diagnosed

Diagnosis begins with your symptom history and a pelvic examination, but imaging is required for confirmation and surgical planning.

Transvaginal Ultrasound: The First-Line Tool

Transvaginal ultrasound (TVUS) is the standard initial diagnostic test. It is widely available, radiation-free, and accurate for intramural and subserosal fibroids measuring more than 1 cm. ACOG recommends TVUS as the first-line imaging modality for suspected leiomyomas. Submucosal fibroids may require saline infusion sonohysterography (SIS) to define the degree of cavity intrusion, which directly informs fertility and bleeding prognosis.

MRI for Surgical Planning

MRI is reserved for complex cases: uncertain ultrasound findings, pre-surgical mapping before myomectomy or uterine fibroid embolization (UFE), or when adenomyosis needs to be distinguished from fibroids. MRI characterizes fibroid number, size, and precise location better than ultrasound and is standard before MRI-guided focused ultrasound ablation.

Endometrial Biopsy: Ruling Out Malignancy

Heavy bleeding in a premenopausal woman with fibroids usually comes from the fibroids, but endometrial hyperplasia and uterine cancer must be excluded when risk factors are present. Any postmenopausal bleeding warrants endometrial biopsy before attributing it to previously diagnosed fibroids. ACOG Practice Bulletin No. 128 states that endometrial sampling should be performed in women aged 45 or older with abnormal uterine bleeding, or in younger women with risk factors for endometrial hyperplasia.

Fibroid Treatment: Matching the Option to Your Life Stage

No single treatment fits every woman with fibroids. The right choice depends on your age, desire for future pregnancy, symptom burden, fibroid size and location, and whether you are in your reproductive years, perimenopause, or postmenopause.

Medical Management: Hormonal and Non-Hormonal Options

Levonorgestrel intrauterine system (LNG-IUS, Mirena). The 52 mg levonorgestrel IUD reduces menstrual blood loss by 70 to 90 percent in most women with fibroids. A Cochrane review confirmed superior reduction in menstrual blood loss with LNG-IUS compared to oral therapies for fibroid-related heavy bleeding. It does not shrink fibroids, but it reliably controls bleeding. It is less effective when the fibroid significantly distorts the uterine cavity.

GnRH agonists (leuprolide acetate, nafarelin). These agents suppress ovarian estrogen production, shrinking fibroids by an average of 35 to 65 percent over three to six months. A key trial published in Obstetrics and Gynecology demonstrated mean uterine volume reduction of 45 percent after three months of leuprolide acetate at 3.75 mg monthly. They are primarily used short-term before surgery to reduce fibroid size, correct anemia, and simplify the procedure. Longer use requires add-back hormone therapy to prevent bone loss and menopausal symptoms.

GnRH antagonists with add-back therapy (relugolix-estradiol-norethindrone, elagolix-estradiol-norethindrone). These oral combinations, sold as Myfembree and Oriahnn respectively, are FDA-approved specifically for fibroid-related heavy menstrual bleeding. In the LIBERTY trial, relugolix combination therapy reduced menstrual blood loss by 84 percent after 24 weeks compared to 15 percent with placebo. Both are limited to 24 months of use due to residual bone density concerns.

Tranexamic acid. This non-hormonal antifibrinolytic reduces menstrual blood loss by approximately 40 to 50 percent and is taken only during menstruation. It does not affect fibroid size or fertility and is an option for women who cannot or prefer not to use hormonal therapy.

NSAIDs. Mefenamic acid and similar NSAIDs reduce blood loss modestly, around 20 to 30 percent, and help with associated dysmenorrhea. They are appropriate for mild-to-moderate symptoms.

Procedural and Surgical Options

Uterine fibroid embolization (UFE). A radiologist threads a catheter into the uterine arteries and injects particles that cut off blood supply to fibroids. Fibroid volume typically decreases by 40 to 60 percent. A randomized trial published in the New England England Journal of Medicine comparing UFE to hysterectomy found similar quality-of-life improvements at two years, with UFE carrying lower short-term morbidity and shorter hospital stays. UFE is not recommended for women who wish to conceive, as effects on endometrial blood flow are not fully characterized.

Myomectomy. Surgical removal of fibroids while preserving the uterus. It is the preferred surgical option for women who want future pregnancies. Myomectomy can be performed hysteroscopically (for submucosal fibroids), laparoscopically, robotically, or via open laparotomy, depending on fibroid number, size, and location. ASRM practice guidelines state that submucosal fibroids should be removed before IVF cycles to optimize implantation rates.

MRI-guided focused ultrasound (MRgFUS). A non-invasive ablation technique using focused ultrasound waves guided by real-time MRI. It requires no incision and has a rapid recovery. Fibroid size, location, and tissue characteristics must meet specific criteria for candidacy.

Hysterectomy. The only definitive cure for fibroids. It eliminates both the fibroids and the uterus, making it appropriate only for women who have completed childbearing. Route (vaginal, laparoscopic, or abdominal) depends on uterine size, fibroid number, and surgeon expertise.

Fibroids Across Your Life Stage

Reproductive Years (Ages 20 to 45)

This is when fibroids are most symptomatic. Heavy bleeding, dysmenorrhea, and bulk symptoms peak during this phase. Fertility implications are a primary concern. Submucosal fibroids impair implantation and increase miscarriage risk; removing them before attempting conception is generally recommended. For women not yet ready for pregnancy, the LNG-IUS or oral GnRH antagonist combination therapy offers effective medical management.

Trying to Conceive and Pregnancy

A framework for thinking about fibroids in the fertility context: location matters more than size. A 3 cm submucosal fibroid is more likely to impair implantation than a 7 cm subserosal fibroid that leaves the cavity intact. Before any assisted reproductive technology cycle, saline sonohysterography or hysteroscopy should confirm the uterine cavity is unobstructed.

During pregnancy, fibroids may enlarge due to rising estrogen and increased uterine blood flow. Most women with fibroids have uncomplicated pregnancies. Risks include placental abruption, preterm labor, malpresentation, and postpartum hemorrhage, and these risks are higher when fibroids are large or located near the placenta. A 2017 systematic review in the American Journal of Obstetrics and Gynecology found that women with fibroids had a two-fold increased risk of cesarean delivery and a three-fold increased risk of postpartum hemorrhage.

Perimenopause (Typically Ages 45 to 55)

Fluctuating estrogen during perimenopause can temporarily worsen fibroid symptoms before they eventually improve. Heavy bleeding in perimenopause from fibroids overlaps symptomatically with anovulatory cycles, making it harder to attribute blood loss to a single cause. Managing anemia and controlling bleeding medically is often the goal during this transitional phase, since fibroids will typically regress once menopause is reached.

Postmenopause

Fibroids shrink after menopause as estrogen falls. Any woman with previously diagnosed fibroids who experiences new postmenopausal bleeding should not assume the fibroids are the source. Postmenopausal bleeding always requires endometrial biopsy to exclude malignancy, even if fibroids are visible on imaging.

Women on systemic menopausal hormone therapy (MHT) may find their fibroids remain stable or modestly enlarge due to exogenous estrogen. This does not automatically preclude MHT use, but fibroid size and symptom burden should be monitored at regular intervals.

Pregnancy and Lactation: The Essential Safety Considerations

Most fibroid-directed medical therapies are contraindicated in pregnancy.

GnRH agonists and antagonists are contraindicated during pregnancy and lactation. GnRH agonists can cause fetal harm through suppression of pituitary gonadotropins. Relugolix, the active component of Myfembree, carries no established human pregnancy safety data, and its use during pregnancy is not recommended. The FDA prescribing information for Myfembree requires a negative pregnancy test before initiation and recommends a reliable non-hormonal contraceptive method during and for one week after stopping treatment, since the estradiol component may mask pregnancy recognition.

Levonorgestrel IUD: Approved for use in reproductive-aged women and is one of the safest options for women who may wish to conceive later, as fertility returns quickly after removal. Not appropriate during active pregnancy.

Tranexamic acid: Classified as FDA Pregnancy Category B based on animal data. Limited human data exist on fetal exposure through breast milk. Most clinicians avoid it during pregnancy unless the bleeding risk is severe.

Myomectomy before conception: For women planning pregnancy within 12 to 24 months, surgical removal of symptomatic fibroids, particularly submucosal or large intramural ones, may improve conception and live birth rates. The uterine incision should be given adequate healing time, typically a minimum of three to six months, before attempting pregnancy, and mode of delivery should be discussed with your surgeon based on incision depth.

Who This Is Right For and Who Should Consider Alternatives

Not every woman with fibroids needs treatment. Asymptomatic fibroids discovered incidentally on imaging do not require intervention. The decision to treat is driven by symptoms, fertility goals, and quality of life.

Medical management is appropriate for you if: You have moderate symptoms, prefer to avoid surgery, are approaching perimenopause (and can wait for natural fibroid regression), or want to preserve fertility and are addressing the fibroid-related bleeding while planning for conception.

Surgical or procedural management is appropriate if: Symptoms are severely affecting quality of life, anemia is refractory to medical management, fibroid size is causing significant bulk symptoms, or fertility requires a clear uterine cavity that medical therapy cannot provide.

Watchful waiting is appropriate if: Fibroids are small, incidentally found, and you have no significant bleeding, pain, or fertility concerns. Annual monitoring with ultrasound is reasonable.

Women who are in perimenopause and within a few years of natural menopause may reasonably choose medical symptom management and surveillance rather than surgery, since menopause-related regression is anticipated.

The Evidence Gap in Women's Health

Women have been historically underrepresented in clinical trials for conditions outside of direct reproductive medicine, and fibroid research is no exception. Most large trials on GnRH antagonists used in fibroids enrolled predominantly white women, limiting the generalizability of those findings to Black women, who bear the greatest fibroid burden. A 2021 analysis in the American Journal of Obstetrics and Gynecology noted that race-disaggregated efficacy and safety data for fibroid treatments remain sparse, with calls for dedicated trials in high-burden populations. When your clinician discusses treatment options, it is fair to ask whether the evidence base reflects women with your background.