Secondary Amenorrhea

Secondary Amenorrhea - Amenorrhea Unmasked

Secondary amenorrhea: Cessation of menses after menarche.

• Diagnostic Criteria:
  • Previously regular cycles: No menses for ≥3 months.
  • Previously irregular cycles: No menses for ≥6 months.
• Key Initial Investigations ("Unmasking"):
  • 1. Exclude Pregnancy: β-hCG test is paramount.
  • 2. TSH: Screen for thyroid dysfunction.
  • 3. Prolactin: Detect hyperprolactinemia.
  • 4. Progestin Challenge Test (PCT): Evaluates estrogen status and outflow tract integrity. If withdrawal bleed occurs, indicates anovulation.

⭐ The most frequent cause of secondary amenorrhea is pregnancy.

Secondary Amenorrhea - The No-Show Culprits

Defined as absence of menses for >3 months in women with previously regular cycles, or >6 months in women with previously irregular cycles. Always exclude pregnancy first (β-hCG test).

• Hypothalamic Dysfunction (↓GnRH → ↓FSH, ↓LH, ↓E2)
  • Functional Hypothalamic Amenorrhea (FHA): Stress, excessive exercise (Female Athlete Triad), weight loss (anorexia nervosa).
  • Kallmann Syndrome: GnRH deficiency with anosmia.
• Pituitary Disorders
  • Hyperprolactinemia: ↑Prolactin (e.g., prolactinoma) inhibits GnRH.
  • Sheehan's Syndrome: Postpartum pituitary necrosis.
  • Empty Sella Syndrome.
• Ovarian Dysfunction
  • Premature Ovarian Insufficiency (POI): Ovarian failure before age 40 (↑FSH, ↑LH, ↓Estradiol).
  • Polycystic Ovary Syndrome (PCOS): Chronic anovulation, hyperandrogenism.
• Uterine/Outflow Tract Abnormalities (Normal HPO axis)
  • Asherman's Syndrome: Intrauterine adhesions, often post-instrumentation.
  • Cervical Stenosis.
• Other Endocrine Disorders
  • Thyroid dysfunction (Hypo- or Hyperthyroidism).
  • Cushing's syndrome.

Key Investigations: β-hCG, TSH, Prolactin, FSH, LH, Estradiol. Progestogen challenge test helps differentiate anovulation from outflow tract obstruction.

⭐ Asherman's syndrome, characterized by intrauterine adhesions typically following uterine instrumentation (e.g., D&C), is a key cause of secondary amenorrhea with normal hormonal profiles (FSH, LH, Estradiol).

Secondary Amenorrhea - Star Syndromes Spotlight

Key conditions causing menses absence >3 cycles or >6 months.

• Polycystic Ovary Syndrome (PCOS)
  • Rotterdam (2/3): Oligo/anovulation, hyperandrogenism (clin/biochem), PCO on USG (string of pearls).
  • Labs: ↑LH/FSH ratio (often >2:1), ↑Testosterone, Insulin Resistance.

  ⭐ In PCOS, the LH:FSH ratio is often >2:1, though not a mandatory diagnostic criterion.

• Asherman Syndrome
  • Intrauterine adhesions (IUAs).
  • Cause: Post-curettage, endometritis.
  • Diagnosis: Hysteroscopy (gold standard), HSG.
  • Treatment: Hysteroscopic adhesiolysis.
• Sheehan Syndrome
  • Postpartum pituitary necrosis.
  • Cause: Severe PPH & hypotension.
  • Features: Failure to lactate, amenorrhea, hypothyroidism, adrenal insufficiency symptoms.
  • ↓Pituitary hormones.
• Premature Ovarian Insufficiency (POI)
  • Ovarian failure <40 years.
  • Symptoms: Amenorrhea, menopausal (hot flashes).
  • Labs: ↑FSH (>25-40 IU/L on 2 occasions), ↓Estrogen.
  • Karyotype if <30 yrs (e.g., Turner mosaic).

Secondary Amenorrhea - Charting the Course

• Initial Steps: Exclude pregnancy, assess TSH & prolactin.
• Progestin Challenge: Differentiates anovulation from hypoestrogenism/outflow issues.
• Further Evaluation: FSH/LH, estradiol, imaging if needed.

⭐ Asherman syndrome (intrauterine adhesions) is a key cause of secondary amenorrhea with a negative progestin challenge test and no withdrawal bleed after estrogen-progestin challenge, often post-instrumentation (D&C).

High‑Yield Points - ⚡ Biggest Takeaways

• Secondary amenorrhea: No menses >3 months (regular cycles) or >6 months (irregular cycles).
• Pregnancy is the most common cause; always perform β-hCG test first.
• Initial investigations include β-hCG, TSH, and prolactin.
• Progestin challenge test helps assess endogenous estrogen and outflow tract patency.
• Asherman syndrome (intrauterine adhesions) and PCOS are important structural and endocrine causes.
• Functional Hypothalamic Amenorrhea (FHA) is common in athletes or due to stress/low weight.
• Premature Ovarian Insufficiency (POI) presents with ↑FSH before age 40.