What causes a missed period?

Pregnancy is one possible explanation when you have had sex that could lead to pregnancy, so a home test may be useful. Ovulation can also pause when the body is under significant stress, has low energy availability, or is recovering from illness. Changes in weight, intense exercise, and some medicines can affect the hormone signals that coordinate ovulation and bleeding.

Polycystic ovary syndrome can make ovulation irregular. High prolactin can interfere with the menstrual cycle, sometimes alongside breast milk production. Hypothalamic amenorrhoea is another pattern linked with changes in energy balance or stress. Perimenopause can make periods unpredictable as ovarian hormone patterns change.

Record the date of your last bleed, usual cycle pattern, contraception, medicines, recent illness, exercise, weight changes, stress, and symptoms such as pelvic pain or unusual discharge. Take a pregnancy test when relevant and repeat or seek advice if the result does not fit your symptoms. A clinician may review your history and arrange targeted tests rather than treating every missed period in the same way.

Arrange an appointment if missed periods recur, your cycles change noticeably, or you have symptoms such as headaches, vision changes, excess facial hair, or nipple discharge. Seek urgent care for severe or one-sided pelvic pain, fainting, shoulder-tip pain, or heavy bleeding when pregnancy is possible, because these symptoms need prompt assessment.

Could pregnancy, medication, stress, or an endocrine condition explain this change? Which tests are appropriate? How might polycystic ovary syndrome or perimenopause affect my cycle? What symptoms should make me seek urgent help?