Amenorrhea is a condition in which a woman misses one or more menstrual cycles. The causes are quite numerous, making it difficult for many women to determine the exact reason why they have missed at least one period. There are two kinds of amenorrhea: primary amenorrhea and secondary amenorrhea. Secondary amenorrhea is the most common and may be caused by a wide range of issues, such as pregnancy, stress, low body weight, a tumor on the pituitary gland, uterine problems, and thyroid conditions. The primary amenorrhea causes are more severe and include medical issues, such as a lack of reproductive organs, chromosomal abnormalities, pituitary disease and hypothalamus conditions.
The most common amenorrhea causes include pregnancy and breastfeeding. For example, when a woman becomes pregnant, the fertilized egg implants in the uterine wall. Normally, the lining of the uterus is shed once a month causing a period. When the implantation occurs with pregnancy, the lining remains intact to provide nourishment for the fetus. Consequently, the woman will miss her period during the course of her pregnancy and usually while she is breastfeeding her baby as well.
Other secondary amenorrhea causes include certain medicines and women who use contraceptives. There are some medications, such as oral corticosteroids, antidepressants, and chemotherapy drugs that may cause a woman’s period to stop. In addition, some women use birth control pills, implants, or injections to stop their periods. When they stop using their contraceptives, it may take several months for their menstrual cycle to become regular again.
Hormones may play a large role in the various causes of amenorrhea. For example, stress can change the way the hypothalamus of the brain functions. The hypothalamus is responsible for regulating a woman’s periods and if a woman is stressed and her hypothalamus is not regulating the menstrual cycle effectively, it can cause her periods to stop until the stress diminishes. Also, hormonal medical conditions, such as polycystic ovary syndrome, may cause missed periods. Polycystic ovary syndrome occurs when estrogen and androgen are kept at high levels instead of rising and falling like they normally would.
Sometimes a woman can control what her amenorrhea causes are. For example, a woman who has an extremely low body weight or who exercises excessively may miss her period. If the woman is anorexic, bulimic, or has another form of eating disorder, her period may stop as well.
Other more severe amenorrhea causes can include thyroid problems, pituitary conditions, and uterine issues. For example, hypothyroidism or a thyroid that is underactive may cause amenorrhea. If a tumor is on the pituitary gland, it may cause an increase in the production of proactin, the hormone that regulates a woman’s period. Once the tumor is removed, the woman’s menstrual cycle should resume. Some women miss their periods if they are affected by uterine scaring or ovarian insufficiency as well.
Although only a small percentage of women and teens have primary amenorrhea, the primary amenorrhea causes can be quite difficult to diagnose. Some women suffer from chromosomal abnormalities that deplete their eggs, causing their periods to stop. Other women suffer from a tumor on the hypothalamus. Its removal will typically help the hypothalamus to function properly and cause the periods to start again. In rare cases, a woman may be born without reproductive organs, preventing her from ever having menstrual cycles.