You should talk to your doctor.

The absence of periods is called amenorrhea.

Missing an occasional period is common. It usually is not due to any disorder. A medical evaluation is not typically needed until you miss periods for three or more cycles.

The most common cause of amenorrhea is pregnancy. If you might be pregnant, you can take a pregnancy as early as one week after a missed period.

Other causes of amenorrhea include:

Uterine disease
Damage to the lining of the uterus (the endometrium) can result from infection or scarring from surgery. This condition is called Asherman's syndrome. The scar prevents the endometrium from growing and then shedding as the period. Asherman's syndrome prevents pregnancy but does not have other health risks.

Ovarian disease
Ovarian failure leads to amenorrhea because of the loss of the hormones estrogen and progesterone. The ovaries "fail" in all women at menopause. But if the ovaries stop working before age 40, the condition is called premature ovarian failure. Many times the reason for this is unknown. Known causes include damage from chemotherapy or radiation, genetic syndromes, and autoimmune disorders.

Disorders of the pituitary gland and hypothalamus
These disorders cause amenorrhea because the organs control ovarian function. Thyroid disease, stress, chronic illness, intense physical training, and eating disorders can all disrupt the function of the hypothalamus and pituitary gland. The result is that the ovary fails to release an egg and secrete the hormones that produce a normal menstrual cycle. The ovary in most cases will continue to produce estrogen. This unopposed estrogen increases the risk of uterine cancer.

Treating amenorrhea depends on the cause and the woman's reproductive goals.

If amenorrhea is associated with low estrogen levels, the woman may have menopausal symptoms (hot flashes, sleep disorders) that need treatment. Other problems with early estrogen loss are an increased risk of osteoporosis and heart disease.

The treatment is different if amenorrhea is due to a disorder in which estrogen continues to be produced. Prolonged exposure to unopposed estrogen leads to a higher risk of uterine cancer. This can be treated with progesterone. In addition, a woman with amenorrhea who wants to become pregnant will need treatments aimed at helping her ovaries to ovulate.