Amenorrhea is the absence of menstrual periods in someone who would normally have them. It is a symptom rather than a disease, and pregnancy is the most common reason periods stop.
Doctors describe two main types. Primary amenorrhea means periods have not started by around age 15. Secondary amenorrhea means periods that used to come have stopped for several months in a row.
Pregnancy is the most common cause of a missed period. Other common causes include breastfeeding, stress, sudden weight loss, being overweight, doing a lot of exercise and some types of hormonal contraception. Medical conditions can also stop periods, for example PCOS, an overactive or underactive thyroid, and the start of perimenopause.
A GP appointment is a good idea if you have missed three periods in a row, your periods have not started by 15, or periods have become irregular. Other changes such as tiredness, weight change or new facial hair are also worth mentioning. A doctor may ask about your health, offer blood tests and refer you to a specialist if needed. Treatment depends on the cause.
Missed periods are not painful in themselves, but the cause behind them can affect energy, mood and concentration. Tests and specialist visits can take time. Flexible hours for appointments and a manager who keeps health conversations private can make this easier.
Sources: NHS, MedlinePlus.