Missed periods

Missed periods (amenorrhoea) means menstruation has stopped or not started. Doctors distinguish primary amenorrhoea (periods never beginning by the expected age) from secondary amenorrhoea (periods stopping in someone who previously had them). By far the most common and important cause to consider first in someone of reproductive age is pregnancy — so a pregnancy test is the starting point. Beyond pregnancy, the menstrual cycle depends on a chain running from the brain (hypothalamus and pituitary) to the ovaries, and a problem anywhere along it can stop periods. Common causes include the natural transition toward menopause and, at the younger end, primary ovarian insufficiency; polycystic ovary syndrome (PCOS), which causes irregular or absent periods with signs of excess androgens; a high prolactin (sometimes from a small pituitary growth); thyroid disease, both over- and underactive; and the hypothalamus 'switching off' the cycle in response to very low body weight, intense exercise, or significant stress (functional hypothalamic amenorrhoea). Breastfeeding and hormonal contraception also stop or change periods, as expected. Because the causes span pregnancy, the ovaries, the pituitary and the thyroid, missed periods are worked up with a pregnancy test first and then a targeted set of hormone tests.

• Pregnancy — the most common cause; always the first to check.
• Menopause or perimenopause — periods naturally becoming irregular then stopping.
• Primary ovarian insufficiency — early loss of ovarian function.
• Polycystic ovary syndrome (PCOS) — irregular or absent periods with androgen excess.
• High prolactin — sometimes from a small pituitary growth.
• Thyroid disease — over- or underactive thyroid.
• Low body weight, intense exercise or stress — functional hypothalamic amenorrhoea.
• Breastfeeding or hormonal contraception — expected effects.

The first and essential test for missed periods in someone of reproductive age is a pregnancy test (beta-hCG). If that is negative, a targeted hormone panel follows: FSH and LH (with estradiol) to assess the ovaries and detect the menopausal or ovarian-insufficiency pattern; prolactin, which if high can stop periods; thyroid function (TSH); and, where excess androgens are suspected (as in PCOS), testosterone. The combination usually locates the cause along the brain–pituitary–ovary axis. Mediora.AI can surface these patterns from your results — a high FSH suggesting ovarian insufficiency or menopause, a high prolactin, or a thyroid abnormality — helping frame the picture, though a pregnancy test comes first and the interpretation belongs with your doctor.