Missed Period After Faint Positive and Negative Tests: Comprehensive Differential

Possible Explanations

1. Early pregnancy loss (chemical pregnancy): Initial low hCG detected, then spontaneous loss → subsequent negatives.
2. Hormonal disorders: PCOS (oligo‑ovulation), thyroid dysfunction (hypo/hyper), hyperprolactinemia.
3. Stress: Hypothalamic suppression → anovulation.
4. Medications: OCPs, antipsychotics, antidepressants, chemotherapy, glucocorticoids.
5. Perimenopause: Irregular cycles in late 40s/early 50s.
6. Ectopic pregnancy: Low‑rising hCG; risk of rupture → emergency.
7. Weight extremes: Low BMI (hypothalamic amenorrhea) or obesity (insulin resistance).
8. Other: Pituitary tumor, ovarian failure, Asherman’s syndrome.

Recommended Workup

• Quantitative serum β‑hCG (repeat 48 h).
• TSH, prolactin, FSH/LH, estradiol, testosterone.
• Pelvic ultrasound (ovarian morphology, endometrial thickness).
• Review medications, stress, weight history.

When to Act Urgently

Abdominal pain + positive/low hCG → rule out ectopic. Heavy bleeding, syncope, shoulder tip pain → ER.