Amenorrhea

Natural occurrences

• Pregnancy. When you are pregnant, you don’t ovulate, so your period stops temporarily. Pregnancy is the most common cause of secondary amenorrhea.
• Breastfeeding.
• Menopause.

Hormone imbalances

• Hormone levels. When hormones are irregular, menstruation can be prevented. Irregular hormone levels are the most common cause of primary amenorrhea. Hypogonadotropic hypogonadism or functional hypothalamic amenorrhea is one of the most common types of secondary amenorrhea, when the sex organs produce too few hormones because of an issue with the hypothalamus or pituitary gland.
• Ovulation problems. These are usually the cause of very irregular periods or frequently missed periods.
• Pituitary tumor. A benign (non-cancerous) tumor in the pituitary gland can interfere with the hormone regulation of menstruation.
• Polycystic Ovarian Syndrome (Polycystic Ovary Syndrome). Also known as PCOS, Polycystic Ovary Syndrome causes high and sustained levels of hormones, preventing fluctuation as in a normal menstrual cycle. People with Polycystic Ovary Syndrome need lifelong treatment to prevent health complications and to regulate cycles.
• Premature menopause (primary ovarian Insufficiency). Menopause typically occurs after age 50, but some people younger than 40 experience ovarian insufficiency or premature ovarian failure, when the supply of eggs diminishes early and the menstrual cycle stops at a younger age.
• Thyroid gland disorder. If you have an underactive thyroid (hypothyroidism) or an overactive thyroid (hyperthyroidism) your periods may stop.

Medications

Certain medications can stop the menstrual cycle, including

• Allergy medications.
• Antidepressants.
• Antipsychotics.
• Blood pressure medications.
• Chemotherapy.

Contraceptives. Oral contraceptives such as the birth control pill can cause menstrual irregularity or even stop menses altogether. Even after stopping taking a birth control pill, regular ovulation and menstrual function may take a while to resume. Alternative contraceptive measures such as those injected or implanted as well as an IUD can cause amenorrhea.

Lifestyle factors

• Eating disorders. If you have anorexia or bulimia, you may develop amenorrhea. This is because extreme weight loss makes your body weight too low to sustain a pregnancy. To protect the body, the reproductive system “shuts down” by interrupting hormone production and stopping ovulation because it’s severely malnourished. Excessively low body weight is classified as about 10% under normal weight.
• Over-exercise or strenuous exercise. If you exercise a lot, your periods may stop due to low body fat content from weight loss, stress and high energy expenditure.
• Obesity. If you have experienced rapid weight gain or are overweight, you may have amenorrhea as a result of excess fat cells getting in the way of the process of ovulation.
• Stress. Mental and physical stress can alter the hypothalamus function, resulting in the stop of ovulation and menstruation (known as hypothalamic amenorrhea). Regular cycles typically resume when stress decreases.

Defects or structural problems

If your period hasn’t started by age 16, it may be due to a birth defect, anatomical defect or other medical condition.

• Chromosomal abnormality. When chromosomes are missing or in excess, they can create defects such as Turner Syndrome, when one of the X chromosomes is missing. This prevents the ovaries from developing.
• Missing reproductive organs. During fetal development, problems can arise and lead to birth defects such as mullerian agenesis (missing the uterus), cervix, vagina or other elements of the reproductive systems. Because of the lack of a fully-developed reproductive system, menses will not occur later in life.
• Structural abnormalities of the vagina. Any obstruction of the vagina may prevent visible menstrual bleeding or hinder menses. Sometimes a membrane within the vagina blocks the blood flow from the uterus and cervix.
• Uterine scarring. A condition known as Asherman’s syndrome can cause scar tissue to build in the lining of the uterus. Uterine scarring prevents the normal buildup and shedding of uterine tissue. It can be caused by uterine fibroids, or sometimes a cesarean section or dilation and curettage.

• Cardiovascular disease. A lack of estrogen can also cause cardiovascular problems, making someone at increased risk of heart attack or problems with the heart muscle and blood vessels.
• Infertility. Amenorrhea prevents ovulation, which in turn means you cannot get pregnant. The hormone imbalances that cause amenorrhea also increase the likelihood of a miscarriage or other complications with pregnancy.
• Osteoporosis. Hormonal problems that cause amenorrhea such as a lack of Estrogen can cause osteoporosis, the weakening of bones. The decreased bone density and bone loss can make you more likely to get hip and wrist fractures, as well as make it more difficult to perform general activities.
• Ovarian cancer. Those with irregular cycles that are older are twice as likely to develop ovarian cancer in their 70s that those without problems like amenorrhea.
• Pelvic pain. If an anatomical abnormality is causing amenorrhea, it can also cause pelvic pain
• Psychological stress. Young women who are going through puberty can experience stress if they do not get their period, especially when compared to their peers.