Why Is My Period Late?

A late period can feel alarming, but there are many possible causes — most of them benign. Here's a calm breakdown of the most common reasons, and when to take action.

Pregnancy

First thing to rule out if you're sexually active and not on reliable contraception. A home pregnancy test is most accurate from the day your period was due, but more reliable a few days later.

Stress

Severe or prolonged stress affects the hypothalamus, which controls reproductive hormones. Cycles can lengthen, become irregular, or pause entirely. Stress that disrupts your cycle is worth taking seriously even when it feels 'normal'.

Weight, exercise, and diet

Significant weight loss, very low body fat, or intense exercise (especially endurance) can disrupt cycles. The body deprioritizes reproduction when it perceives scarcity. Eating disorders frequently cause amenorrhea (missing periods).

Thyroid and other hormones

Both hyperthyroidism and hypothyroidism can affect cycles. PCOS frequently causes irregular or missing periods. Elevated prolactin (from breastfeeding or certain medications) can also pause cycles.

Perimenopause

If you're in your 40s, perimenopause can cause cycle irregularity that may last several years before periods stop altogether. Worth tracking carefully — perimenopause has its own health considerations.

When to see a doctor

Missed periods for 3 months with a negative pregnancy test, or persistent irregularity, deserve a doctor visit. Bring your cycle log — it's the most useful thing you can show.