A menstrual cycle consists of several phases during each month. The final phase of the cycle is a menstrual period. The menstrual period, also referred to as menstruation, is the shedding of the lining in the uterus. Amenorrhea is the absence of menstruation. Primary amenorrhea and secondary amenorrhea are the two classifications of the condition. Most females begin to menstruate by the age of 13, according to MedlinePlus. Primary amenorrhea occurs when a female does not begin menstruation before reaching the age of 16. Secondary amenorrhea occurs for many different reasons and is a cessation in menstruation after initial onset.
Pregnancy
Pregnancy is the most common reason for a woman to stop having a menstrual period, according to the American Congress of Obstetricians and Gynecologists. Once pregnancy occurs, the embryo implants in the lining of the uterus, so menstruation stops while a woman carries the baby.
Polycystic Ovarian Syndrome
Polycystic Ovarian Syndrome (PCOS) may cause irregular or absent menstrual periods. A dysfunction in the pituitary gland causes an increase in the production of luteinizing hormone. The excessive luteinizing hormone causes an increase in the male sex hormone, androgen. The increased levels of these hormones prevent the menstrual cycle from performing normally.
Contraceptives and Medications
Females taking birth control pills to prevent contraception may experience a cessation of menstrual periods. Additional contraceptives that may cause amenorrhea include intrauterine devices (IUD) and medications injected or implanted in the body to prevent pregnancy. These products stop menstruation due to the hormones in the contraceptives. In addition to contraceptives, additional medications may cause a lack of menstruation. Common medications that may cause amenorrhea include corticosteroids, antidepressants and antipsychotics.
Lactation
Women who breastfeed and infant may not have a menstrual period. Ovulation may still occur without menstruation so pregnancy is still a possibility for lactating women without their period, according to the Mayo Clinic.
Weight Changes
Women with a body fat percentage less than 15 to 17 percent may experience a lack of menstrual periods, according to MedlinePlus. By contrast, obese women can experience amenorrhea. Fat in the body helps regulate hormone levels in the body. Having too much or too little body fat increases the possibility of amenorrhea.
Stress and Exercise
Conditions that put a strain on the body, such as emotional or physical stress, may cause a female to stop having menstrual periods. Stress may alter the area of the brain that helps regulate hormones, according to the Mayo Clinic. For athletic females who exercise excessively, amenorrhea is common. The stress of the exercise and lack of body fat both contribute to the lack of menstrual periods.
Asherman's Syndrome
A condition of the uterus, called Asherman's syndrome, occurs due to scar tissue inside the uterus. The scar tissue commonly forms due to a Cesarean section, a dilation and curettage or from treatments for fibroids in the uterus. Little or no lining builds in the uterus due to the scar tissue, therefore there is no menstrual period.
Menopause
After the age of 45, women may experience a lack of menstruation due to menopause. This condition marks the end of reproductive years for a woman, and her body stops releasing eggs decreases hormone production. Due to these changes, menstruation stops.
