What can cause irregular periods?

A cycle may be irregular when bleeding comes earlier or later than expected, lasts differently, or is missed. Stress, major changes in eating or exercise, illness, and breastfeeding can alter the hormone signals that control ovulation. Pregnancy is another possibility when it could apply.

Some people have anovulation, meaning an egg is not released regularly. Polycystic ovary syndrome can affect ovulation and may occur with acne or increased facial hair. Perimenopause can make cycles unpredictable, while premature ovarian insufficiency can stop or disrupt periods earlier than expected. Medicines and thyroid conditions can also contribute.

Track the first day of each bleed, how long it lasts, the flow, pain, and any bleeding between periods or after sex. Note pregnancy possibility, recent health changes, weight changes, stress, exercise, and all medicines or supplements. This pattern helps a clinician choose relevant tests.

Treatment depends on the cause and on whether pregnancy is wanted. Options may include treating an underlying condition, regulating bleeding, or supporting ovulation. Do not start hormonal treatment or metformin without advice suited to your medical history.

Arrange an appointment for a new or persistent change, repeated missed periods, very heavy bleeding, bleeding after sex, or difficulty becoming pregnant. Seek urgent care for soaking-heavy bleeding with dizziness, faintness, severe pain, or possible pregnancy with pain or bleeding.

Ask whether pregnancy testing, blood tests, or an examination is appropriate; whether your symptoms suggest irregular ovulation; and how treatment would affect contraception or plans for pregnancy. Ask when to return if the pattern continues.