Sudden Irregular Periods in Your 20s and 30s: Causes and Tests
Sudden irregular periods in your 20s or 30s are most often caused by pregnancy, stress, weight change, a thyroid disorder, high prolactin or PCOS. Less commonly, the ovaries are slowing early. A pregnancy test, TSH, prolactin, reproductive hormones and an ultrasound usually find the cause, and most causes are reversible with treatment.