WebMD explains that weight gain in the belly area accompanied by a lack of menstruation very likely signals primary amenorrhea in young women who have not had their periods by the age of 16. It likely signals secondary amenorrhea in adult women who have a previous history of normal periods that have stopped for three or more months.
Healthline notes that most often, changes in menstruation patterns are linked to simple lifestyle changes, such as sudden fluctuations in diet and activity levels. If a patient is sure that she is not pregnant and is experiencing an abnormal absence of menstruation, she should consider her age and menstruation history to help determine if she potentially has a medical condition. If she suspects that she may have primary or secondary amenorrhea, WebMD advises that she schedule an appointment with her primary physician or gynecologist to further asses her range of symptoms and medical history. However, it is not uncommon for doctors to be unable to explain the cause of primary amenorrhea, but possible factors have been linked to ovary failure, Turner syndrome, Sawyer syndrome and central nervous system complications.
According to Healthline, only 1 percent of females experiences primary amenorrhea. Secondary amenorrhea affects approximately 4 percent of women and is linked to hormonal imbalances, stress, thyroid disorders, polycystic ovarian syndrome and suddenly quitting birth control pills.