Amenorrhea

Amenorrhea is the absence of menstrual periods in a person of reproductive age. It is classified as primary when menstruation has never begun and secondary when previously established periods stop.

Hypothalamic amenorrhea: A form of amenorrhea caused by reduced signaling from the hypothalamus to the reproductive hormone system. Stress, intense exercise, or low energy availability can suppress hypothalamic signals and stop periods.
Menstruation: The periodic shedding of the uterine lining through the vagina when pregnancy has not occurred. Amenorrhea describes the absence of this recurring process.
Pregnancy test: A test that detects human chorionic gonadotropin to determine whether pregnancy is present. Pregnancy is generally checked first when periods stop.
Primary amenorrhea: Amenorrhea in someone who has not begun menstruating by the expected age or developmental milestone. This subtype is defined by menstruation never having started.
Osteoporosis: A skeletal disorder marked by reduced bone strength and increased risk of fracture. Long-lasting estrogen deficiency can weaken bones and raise osteoporosis risk.
Polycystic ovary syndrome: A hormonal disorder that can cause irregular ovulation, elevated androgens, and multiple small ovarian follicles. Infrequent or absent ovulation can make periods irregular or absent.
Menstrual cycle: The recurring hormonal and reproductive changes that prepare the ovaries and uterus for possible pregnancy. Periods depend on coordinated changes across the menstrual cycle.
Pelvic ultrasound: Imaging that uses sound waves to examine pelvic organs, including the uterus and ovaries. It can assess uterine anatomy, ovarian appearance, and some structural causes of absent periods.
Secondary amenorrhea: The cessation of menstruation after periods have previously begun, outside expected causes such as pregnancy or menopause. This subtype is defined by periods stopping after they were established.
Infertility: The inability to achieve pregnancy after a period of regular unprotected sexual intercourse. Some causes of amenorrhea also prevent ovulation and conception.

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