Menstrual Disorders and Pelvic Pain¶
Chapter 405 | Part 12: Endocrinology and Metabolism
KEY CLINICAL POINTS¶
- Primary amenorrhea (<1% prevalence) is defined as absence of menarche by age 16, while secondary amenorrhea involves cessation of menstrual cycles for ≥ 3 months.
- Polycystic ovary syndrome (PCOS) accounts for ~30% of secondary amenorrhea and is characterized by hyperandrogenism, irregular cycles, and polycystic ovaries.
- The PALM-COEIN system classifies abnormal uterine bleeding (AUB) into structural (polyps, fibroids, malignancy) and nonstructural (ovulatory dysfunction, coagulopathy) causes.
- Hypogonadotropic hypogonadism (IHH) is associated with anosmia in 50% of cases (Kallmann syndrome) and requires evaluation for genetic causes in ~50% of patients.
- Pelvic pain evaluation must exclude life-threatening conditions like ectopic pregnancy, PID, or ovarian torsion using clinical findings and imaging.
1. DEFINITION & OVERVIEW¶
Amenorrhea is absence of menstrual periods, classified as primary (never menstruated) or secondary (cessation ≥ 3 months). Abnormal uterine bleeding (AUB) describes irregularities in menstrual cycle frequency, duration, or volume. Pelvic pain may arise from reproductive, gastrointestinal, or musculoskeletal sources.
Prevalence of Amenorrhea by Reproductive System Level¶
| Level | Primary Amenorrhea (%) | Secondary Amenorrhea (%) |
|---|---|---|
| Hypothalamus | 28% | 36% |
| Pituitary | 2% | 15% |
| Ovary | 43% | 12% |
| Uterus/Outflow Tract | 19% | 7% |
1.1 Classification of Amenorrhea¶
Primary amenorrhea: Absence of menarche by age 16. Secondary amenorrhea: Cessation of menstrual cycles for ≥ 3 months. Oligomenorrhea: Irregular cycles with <8 periods/year.
1.2 Abnormal Uterine Bleeding (AUB)¶
AUB replaces 'dysfunctional uterine bleeding' and includes irregularities in menstrual cycle length (21–35 days), duration (4–7 days), or blood loss (<80 mL). PALM-COEIN system categorizes etiologies into structural and nonstructural causes.
2. EPIDEMIOLOGY¶
Primary amenorrhea affects <1% of women; 3–5% of women experience secondary amenorrhea. Risk factors include obesity, PCOS, and genetic disorders. Global variations in age at menarche and amenorrhea prevalence are influenced by nutrition and socioeconomic factors.
2.1 Demographics¶
Race/ethnicity does not influence amenorrhea prevalence. Early puberty is increasingly common, particularly in obese girls, but menarche age remains relatively stable.
2.2 Risk Factors¶
Obesity, PCOS, hypothalamic dysfunction, genetic syndromes (Turner syndrome, AIS), and chronic diseases (diabetes, Cushing’s syndrome) increase risk.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Amenorrhea results from hypothalamic-pituitary-gonadal axis dysfunction or uterine/outflow tract abnormalities. PCOS is linked to insulin resistance and hyperandrogenism. Functional hypothalamic amenorrhea (HA) occurs with energy imbalance and stress.
Algorithm for Evaluation of Amenorrhea¶
| Step | Action |
|---|---|
| 1 | Rule out pregnancy (b-hCG) |
| 2 | Assess FSH levels to determine ovarian vs. central cause |
| 3 | Evaluate hyperandrogenism (total/free testosterone) |
| 4 | Perform pelvic ultrasound for structural abnormalities |
| 5 | MRI for hypothalamic/pituitary dysfunction |
3.1 Hypothalamic Causes¶
Kallmann syndrome (anosmia + IHH), functional HA (stress, eating disorders), and genetic mutations (WNT4, FGFR1).
3.2 Ovarian Causes¶
Premature ovarian insufficiency (POI), PCOS, and genetic disorders (FMR1 premutation, Turner syndrome).
3.3 Uterine Causes¶
Congenital müllerian agenesis, obstructive anomalies (imperforate hymen, transverse vaginal septum), and Asherman’s syndrome.
4. CLINICAL FEATURES¶
Symptoms include irregular cycles, cyclic/pelvic pain, and infertility. Complications include endometrial hyperplasia, osteoporosis, and cardiovascular risks. Pelvic pain may reflect gynecologic (PID, endometriosis) or extrapelvic (gastrointestinal, urologic) causes.
4.1 Amenorrhea Symptoms¶
Irregular cycles, infertility, hot flashes, vaginal dryness. Secondary amenorrhea may present with cyclic pelvic pain or postpartum amenorrhea.
4.2 Pelvic Pain¶
Acute pain may indicate ectopic pregnancy, PID, or ovarian torsion. Chronic pain is often due to endometriosis, fibroids, or adenomyosis.
5. DIFFERENTIAL DIAGNOSIS¶
Consider pregnancy, PCOS, hypothalamic dysfunction, thyroid disease, hyperprolactinemia, and structural abnormalities. Exclude endocrine disorders (Cushing’s, Addison’s) and medications (opiates, glucocorticoids).
5.1 Common Causes¶
Pregnancy, PCOS, functional HA, POI, Asherman’s syndrome, and uterine fibroids.
5.2 Red Flags¶
Acute pelvic pain, hemodynamic instability, or abnormal vaginal bleeding may indicate ectopic pregnancy or PID.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnostic workup includes pregnancy testing, hormonal assays (FSH, LH, AMH), pelvic ultrasound, and MRI. The Rotterdam criteria (2023) define PCOS as irregular cycles + hyperandrogenism + polycystic ovaries.
Gynecologic Causes of Pelvic Pain¶
| Acute | Chronic |
|---|---|
| Ruptured ovarian cyst | Endometriosis |
| Ectopic pregnancy | Adenomyosis |
| PID | Pelvic congestion syndrome |
| Ovarian torsion | Uterine fibroids |
| Threatened abortion | Pelvic malignancy |
6.1 Laboratory Tests¶
Measure FSH, LH, estradiol, prolactin, AMH, and thyroid function. Test for anti-ovarian antibodies in autoimmune disorders.
6.2 Imaging¶
Pelvic ultrasound to assess ovarian morphology and uterine abnormalities. MRI for hypothalamic/pituitary lesions.
7. MANAGEMENT & TREATMENT¶
Hormonal therapy (combined contraceptives, progestins), antiandrogens (spironolactone), and lifestyle modifications. Ovulation induction with clomiphene or letrozole for fertility. Surgical intervention for structural abnormalities.
7.1 PCOS Management¶
First-line: combined hormonal contraceptives. Metformin for insulin resistance. Ovulation induction with letrozole or clomiphene. Oocyte donation for POI.
7.2 Pelvic Pain Treatment¶
NSAIDs for acute pain. Laparoscopic excision for endometriosis. Hormonal suppression for adenomyosis. Surgical removal of fibroids or cysts.
8. PROGNOSIS & COMPLICATIONS¶
POI increases risk of osteoporosis and cardiovascular disease. PCOS is linked to metabolic syndrome, infertility, and gestational diabetes. Untreated amenorrhea may lead to endometrial hyperplasia and cancer.
8.1 Long-Term Risks¶
POI: 50% risk of osteoporosis. PCOS: 3–5x higher risk of endometrial cancer. Functional HA: bone density loss with estrogen deficiency.
8.2 Fertility Outcomes¶
PCOS: 70–80% spontaneous pregnancy rate. POI: 50% success with oocyte donation. IHH: fertility with GnRH analogs.
9. SPECIAL CONSIDERATIONS¶
Pregnancy: Exclude ectopic pregnancy with β -hCG and ultrasound. Pediatrics: Delayed puberty may reflect IHH or constitutional delay. Elderly: Evaluate for POI or hyperprolactinemia.
9.1 Pregnancy Considerations¶
Screen for gestational diabetes, preeclampsia, and placental abnormalities. Monitor for preterm labor in PCOS patients.
9.2 Genetic Counseling¶
Kallmann syndrome (X-linked) and Turner syndrome require genetic evaluation. FMR1 premutation carriers face increased risk of fragile X syndrome.
10. KEY POINTS & CLINICAL PEARLS¶
- Rule out pregnancy in all amenorrhea evaluations.
- Use the Rotterdam criteria (2023) for PCOS diagnosis.
- Hormonal therapy is first-line for PCOS and functional HA.
- Pelvic pain must exclude ectopic pregnancy, PID, and ovarian torsion.
- POI requires estrogen replacement and bone density monitoring.