Missed Periods: Causes & When to See a Doctor

Secondary amenorrhea (absence of menses ≥3 cycles or ≥6 months) has a broad differential. Pregnancy is the most common cause but not the only one.

Major Categories

• Hypothalamic/pituitary: stress, excessive exercise, low weight, eating disorders, hyperprolactinemia, pituitary tumor.
• Ovarian: PCOS (most common endocrine cause), primary ovarian insufficiency, ovarian tumors.
• Uterine: Asherman's syndrome (intrauterine adhesions).
• Systemic/endocrine: thyroid dysfunction, uncontrolled diabetes, Cushing's.
• Medications: OCPs, depot progestins, antipsychotics, chemotherapy.
• Pregnancy: intrauterine, ectopic.

When to Evaluate

• ≥3 missed periods (or ≥6 months if oligomenorrheic).
• Any missed period with pregnancy risk.
• Associated symptoms: galactorrhea, hirsutism, acne, hot flashes, headache, visual changes.

Workup: β-hCG, TSH, prolactin, FSH/LH, estradiol, androgen panel, pelvic ultrasound.