What Else Can Delay a Period If It’s Not Pregnancy?

With two negative tests, here are the most likely non-pregnancy causes of a 12-day delay.

PCOS: The top hormonal reason in women of reproductive age. Other clues: previously irregular cycles, acne, excess facial or body hair, and difficulty losing weight.

Thyroid dysfunction: Hypothyroidism is particularly common and can disrupt cycle timing. Other signs include fatigue, feeling cold, weight gain, and dry skin. A TSH blood test confirms this quickly.  

Hyperprolactinemia: High prolactin levels (often from a small benign pituitary growth) suppress ovulation. Signs include milky nipple discharge alongside irregular periods.

Stress: High cortisol suppresses the hormonal cascade that triggers ovulation. An unusually stressful few weeks can cause a 1-2 week delay.