Endometriosis in Special Populations: Teens, Athletes, Pregnant Women, and Menopause

What Makes Endometriosis Different Across Life Stages

Endometriosis is not a single, static disease. It is a dynamic, estrogen-dependent condition in which tissue resembling the endometrium grows outside the uterus, triggering inflammation, scarring, and pain. Because estrogen is the main driver, every major hormonal shift in a woman's life changes how endometriosis behaves.

ACOG Practice Bulletin 114 defines endometriosis by its histologic hallmarks: endometrial-like glands and stroma outside the uterine cavity, found most often on the ovaries, posterior cul-de-sac, and uterosacral ligaments. The clinical picture, though, varies by age, reproductive status, hormonal environment, and comorbid conditions.

The World Endometriosis Society consensus estimates a global prevalence of approximately 190 million affected women, yet diagnostic delay still averages 7 to 10 years across most health systems. That delay is not uniform. It is longest in adolescents, in women who are told their pain is "normal," and in athletes whose symptoms are attributed to training.

Why Sex-Specific Physiology Matters Here

Estradiol produced by the ovaries fuels endometriotic lesion growth. Progesterone normally counters this, but many women with endometriosis show progesterone resistance in ectopic tissue, meaning standard luteal-phase progesterone levels do not protect them the way textbooks suggest. This progesterone resistance is one reason oral contraceptives and progestins help some women but fail others.

Endometriosis in Adolescents and Teenagers

Endometriosis in adolescents is underdiagnosed because clinicians and families too often normalize severe menstrual pain. Studies suggest that among adolescents undergoing laparoscopy for chronic pelvic pain, endometriosis is found in up to 70%.

How It Presents Differently in Teens

Adult endometriosis classically presents with dysmenorrhea, dyspareunia, and dyschezia. In adolescents, the picture is less textbook. Pain is often acyclical, meaning it does not track neatly with menstruation. Nausea, school absence, and GI symptoms (bloating, constipation) are frequently the presenting complaints, which can send clinicians down a gastroenterology path for months or years.

Müllerian anomalies, such as an obstructed uterine horn or cervical stenosis, increase the risk of endometriosis by creating retrograde menstruation at high volume. Any teenager presenting with a Müllerian anomaly and pelvic pain should be evaluated for endometriosis.

Diagnosis in Adolescents

ACOG Committee Opinion 760 states that a presumptive clinical diagnosis in adolescents is acceptable when symptoms are consistent and an empiric trial of hormonal therapy is planned, avoiding immediate surgical risk in young patients. Laparoscopy remains the gold standard, but it should not be the first step in a 14-year-old with six months of pelvic pain.

First-line treatment in adolescents mirrors adult management: combined oral contraceptives (COCs) used continuously (to suppress withdrawal bleeding), or progestin-only options such as norethindrone acetate 5 mg daily. The GnRH agonist leuprolide acetate is used in adolescents only with add-back estrogen-progesterone therapy because of the risk to bone mineral density in this critical accretion window.

Bone Health Is a Non-Negotiable Concern

GnRH agonist therapy without add-back in an adolescent is contraindicated by The Endocrine Society guidelines because peak bone mass is still being established between ages 16 and 25. Even six months of estrogen suppression at this stage carries real long-term fracture risk. If GnRH agonist therapy is needed, norethindrone acetate 5 mg/day as add-back is the regimen with the most adolescent safety data.

Endometriosis in Athletes and Active Women

Female athletes present a diagnostic paradox. High pain tolerance, normalization of exercise-related discomfort, and training-related hormonal suppression all obscure endometriosis symptoms.

The Athlete Triad Overlap

The female athlete triad (low energy availability, menstrual dysfunction, low bone density) produces hypothalamic amenorrhea that suppresses estrogen. In theory, lower estrogen should slow endometriotic lesion growth. In practice, many athletes with functional hypothalamic amenorrhea still have significant disease because endometriotic lesions can produce their own local estrogen via aromatase upregulation, independent of ovarian output.

A 2021 cross-sectional study in the Journal of Clinical Endocrinology and Metabolism found that endurance athletes with chronic pelvic pain were significantly less likely than non-athletes to have received a pelvic pain evaluation, suggesting provider-level bias in this population. Pain attributed to overuse, hip pathology, or stress fractures may actually be endometriosis-related.

Practical Diagnostic Approach for Active Women

Pelvic MRI is a reasonable first imaging choice in athletes because it avoids radiation, has sensitivity of approximately 77% and specificity of approximately 96% for deep infiltrating endometriosis, and can also evaluate for structural causes of hip and pelvic pain in one scan.

Transvaginal ultrasound performed by an experienced endometriosis sonographer detects ovarian endometriomas with high accuracy and should not be skipped just because a patient is young or nulliparous. Virginal or sexually inexperienced patients can be offered transabdominal or transrectal ultrasound as alternatives.

Endometriosis and Fertility: The Trying-to-Conceive Population

Endometriosis accounts for 30 to 50% of female infertility cases, making it one of the most common reversible contributors to subfertility. The mechanism is multifactorial: distorted pelvic anatomy, impaired folliculogenesis, reduced oocyte quality, altered tubal motility, and an inflammatory uterine environment hostile to implantation.

Does Surgery Improve Fertility?

The evidence here is stage-dependent. The ESHRE Guideline on Endometriosis (2022) recommends laparoscopic excision of minimal-to-mild endometriosis (ASRM stages I-II) over diagnostic laparoscopy alone, citing a modest but real increase in live birth rates. For moderate-to-severe disease (stages III-IV), surgery improves anatomy but the effect on live birth rates is less clear when IVF is also an option.

Ovarian Endometrioma Surgery: A Critical Tradeoff

Surgical drainage and ablation of ovarian endometriomas reduces the cyst, but a Cochrane review found that excisional surgery for endometriomas significantly reduces ovarian reserve (measured by anti-Müllerian hormone) compared with non-surgical management. For a woman who is also going to do IVF, an endometrioma <4 cm may be better left alone during the stimulation cycle rather than excised.

The WomanRx Decision Framework for Endometriosis and Fertility:

| Your Situation | Consider First | |---|---| | Trying naturally, stage I-II, no prior surgery | Laparoscopic excision, then timed intercourse 6 months | | Endometrioma <4 cm, planning IVF | Proceed to IVF without excision; monitor | | Endometrioma >4 cm, planning IVF | Discuss excision risk to ovarian reserve vs. Aspiration at egg retrieval | | Stage III-IV, age >35 | IVF without delay over repeat surgery in most cases | | Recurrent endometriosis after prior excision | IVF preferred over third surgery per ESHRE 2022 |

Medical Suppression Does Not Improve Natural Fertility

This point is often misunderstood. Three to six months of GnRH agonist therapy before IVF in endometriosis does appear to improve clinical pregnancy rates, but using hormonal suppression while trying to conceive naturally wastes time. Every month on a GnRH agonist is a month with zero chance of natural conception.

Pregnancy and Postpartum: What the Evidence Actually Shows

Many women with endometriosis are told that pregnancy will "cure" their disease. This is one of the most persistent myths in women's health, and it causes real harm when patients delay care hoping pregnancy will fix things.

Does Pregnancy Suppress Endometriosis?

Pregnancy creates a high-progesterone, low-estrogen state with amenorrhea, which does suppress lesion activity during gestation. Some women do experience significant pain relief during and shortly after pregnancy. However, a longitudinal cohort study found that most women with endometriosis experience symptom recurrence within 12 to 24 months postpartum, and a meaningful proportion have lesion growth confirmed on repeat imaging.

Pregnancy Complications in Women With Endometriosis

Endometriosis is not benign in pregnancy. A 2017 meta-analysis in Human Reproduction found significantly elevated risks compared to women without endometriosis:

• Preterm birth: odds ratio approximately 1.65
• Placenta previa: odds ratio approximately 3.0
• Cesarean delivery: odds ratio approximately 1.57
• Small for gestational age: odds ratio approximately 1.28

These risks are highest in women with deep infiltrating endometriosis or prior endometrioma surgery. Prenatal care for women with a known endometriosis diagnosis should include detailed placental localization on anatomy scan and discussion of these elevated risks with the obstetric team.

Postpartum and Lactation

Breastfeeding prolongs amenorrhea and maintains relative estrogen suppression, which may delay symptom recurrence. This is biologically plausible but the data are observational and thin. Women who breastfeed exclusively for six or more months may notice a longer pain-free window postpartum, but this should not be used as a treatment strategy.

Regarding medications used for endometriosis during lactation: COCs are generally deferred in the first six weeks postpartum and used with caution through six months (lactation and infant growth monitoring recommended per WHO Medical Eligibility Criteria, Category 3 in the first six months). Progestin-only pills, the levonorgestrel IUD, and the etonogestrel implant are all WHO MEC Category 1 or 2 during breastfeeding and are the preferred hormonal options for lactating women who need endometriosis suppression.

GnRH agonists are not recommended during breastfeeding due to the effect on lactation physiology and the absence of safety data in nursing infants.

Pregnancy Safety and Contraception Requirements

For women with endometriosis who are not yet ready to conceive, contraception that also suppresses the disease offers a double benefit.

Combined oral contraceptives (COCs): FDA-approved for endometriosis-related pain (norethindrone/ethinyl estradiol, multiple formulations). Not appropriate in pregnancy (Category X for ethinyl estradiol-containing products). Women who may become pregnant should use barrier backup if pill adherence is uncertain.

Dienogest 2 mg/day: A progestin with high endometrial selectivity, used widely in Europe and approved in many countries for endometriosis. A 2010 RCT in Fertility and Sterility found dienogest equivalent to leuprolide acetate for pain reduction with a significantly better bone density profile. Not approved by the FDA for endometriosis specifically but used off-label. Contraindicated in pregnancy; requires reliable contraception.

Levonorgestrel-releasing IUD (52 mg, Mirena): Delivers progestin locally with minimal systemic absorption. ACOG Practice Bulletin 114 lists it as an effective option for endometriosis-related pain. Safe to use until removed when conception is desired. No teratogenicity data concern with the IUD itself, but if pregnancy occurs with IUD in place, remove promptly.

GnRH agonists (leuprolide acetate, nafarelin, goserelin): Contraindicated in pregnancy (FDA Pregnancy Category X). Women of reproductive age must use non-hormonal contraception while on GnRH agonists. These drugs suppress ovarian function, which paradoxically may reduce contraceptive vigilance; counsel patients explicitly.

GnRH antagonists (elagolix/Orilissa, relugolix/Myfembree): Both are FDA-approved for endometriosis pain and both are Pregnancy Category X equivalent (contraindicated; can cause fetal harm). Elagolix's prescribing information requires use with reliable contraception throughout treatment and for one week after the last dose. Relugolix combination tablet labeling requires a negative pregnancy test before initiation and monthly thereafter.

Fertility returns rapidly after stopping GnRH antagonists, typically within one to two menstrual cycles, which is an advantage over GnRH agonists where return of ovulation may take two to four months.

Endometriosis in Perimenopause

The perimenopausal transition, typically from age 40 to 51, brings erratic estrogen fluctuations rather than a clean decline. This hormonal volatility can actually worsen endometriosis symptoms in some women even as ovarian reserve falls.

Why Perimenopause Is Not Relief

Irregular, high-amplitude estrogen spikes in early perimenopause can re-activate quiescent lesions. Women who had well-controlled disease in their 30s sometimes experience a resurgence of pain in their mid-to-late 40s that is not explained by new lesion growth alone. The variable progesterone output of anovulatory cycles compounds this.

A 2020 review in Climacteric noted that endometriosis-related pain scores in perimenopausal women are not significantly lower than in younger reproductive-age women with the same lesion burden. This challenges the assumption that perimenopause is a natural endpoint for the disease.

Management Options in Perimenopause

Progestin-dominant regimens remain first-line. The levonorgestrel IUD provides both endometriosis suppression and the endometrial protection needed if MHT (menopausal hormone therapy) is being considered. Continuous combined OCP (low-dose) is another option for perimenopausal women without contraindications, providing contraception (still needed until 12 months of confirmed amenorrhea after age 50) alongside lesion suppression.

Aromatase inhibitors such as anastrozole or letrozole, typically combined with a progestin to prevent ovarian stimulation, are an evidence-based option for perimenopausal endometriosis refractory to other treatments. A 2011 RCT showed anastrozole 1 mg/day combined with norethindrone acetate reduced endometriosis-associated pain scores by 60% over six months in premenopausal women.

Endometriosis After Menopause

Most clinicians assume endometriosis resolves at menopause. It does not, for a meaningful minority of women.

Persistent Disease After Natural Menopause

Between 2 and 5% of postmenopausal women have active endometriosis confirmed histologically, according to data reviewed by Streuli et al. In Menopause. Risk factors for persistence include high BMI (adipose aromatase produces local estrogen), prior incomplete surgical excision, and use of unopposed estrogen menopausal therapy.

There is also a small but real risk of malignant transformation of endometriosis to clear-cell or endometrioid ovarian carcinoma. The relative risk is approximately 2 to 3 times background risk, per Munksgaard and Blaakaer in Acta Obstetricia. Postmenopausal women with known ovarian endometriomas should be followed with annual transvaginal ultrasound and CA-125.

Hormone Therapy After Menopause With Endometriosis

This is one of the most clinically contested areas in women's health. The Menopause Society (formerly NAMS) 2022 Position Statement does not specifically contraindicate MHT in women with a history of endometriosis, but advises individualized counseling and strong preference for combined (estrogen plus progestogen) rather than unopposed estrogen regimens, to avoid stimulating residual endometriotic tissue.

"For women with a history of endometriosis, use of progestogen alongside estrogen is recommended even after hysterectomy, to prevent stimulation of any residual disease," per The Menopause Society clinical guidance.

Women who had definitive surgical treatment with confirmed excision of all visible disease may be lower risk for recurrence on MHT than those with incomplete excision. However, the data here are observational, not from RCTs, and shared decision-making is necessary.

Endometriosis Co-occurring With PCOS and Other Female Conditions

Endometriosis and PCOS are sometimes framed as opposites (anovulatory vs. Ovulatory, high androgen vs. Normal androgen), but they can and do coexist. A 2015 study in Human Reproduction found PCOS in approximately 6% of women with confirmed endometriosis, a rate comparable to the general population, suggesting the co-occurrence is coincidental rather than mechanistically linked, but not rare enough to dismiss.

The clinical challenge: PCOS causes irregular, heavy periods. Endometriosis causes painful periods. When both are present, pain may be attributed entirely to PCOS-related endometrial buildup, delaying endometriosis diagnosis further.

Women with both conditions often benefit from a progestin-dominant hormonal approach (IUD or continuous progestin) that addresses endometrial shedding in PCOS while suppressing endometriotic lesions simultaneously.

Endometriosis also co-occurs with hypothyroidism (autoimmune thyroid disease is significantly more common in women with endometriosis per a 2019 meta-analysis), interstitial cystitis, and fibromyalgia. A woman presenting with any two of these conditions should prompt clinicians to screen for the others.

Who This Is Right for, and Who Needs a Different Approach

Life Stages and Conditions Where Standard Endometriosis Care Applies

Standard hormonal suppression (COCs, progestins, GnRH modulators) is appropriate for most reproductive-age women with confirmed or clinically suspected endometriosis who are not trying to conceive.

When Standard Care Needs Modification

• Adolescents under 18: Avoid GnRH agonists without add-back therapy. Prioritize bone health alongside pain control.
• Women actively trying to conceive: Hormonal suppression does not improve natural conception rates. Move to fertility evaluation and referral promptly if conception has not occurred within 6 to 12 months.
• Pregnant women: All hormonal endometriosis medications are contraindicated. Management is expectant with acetaminophen for pain; NSAIDs should be avoided after 20 weeks per FDA guidance on fetal kidney risk.
• Lactating women: Progestin-only options (IUD, implant, progestin-only pill) are preferred. Avoid GnRH agonists.
• Perimenopausal women: Ensure contraception is not inadvertently stopped prematurely. Progestin-dominant regimens manage both lesion suppression and endometrial protection.
• Postmenopausal women on MHT: Use combined estrogen-progestogen; avoid unopposed estrogen. Annual surveillance imaging for women with prior endometriomas.
• Women with prior incomplete surgical excision: Higher risk for disease recurrence on any estrogen-containing therapy. More aggressive surveillance warranted.