Reasons Why Menstrual Cycle May Be Late

A late menstrual period can be source of great concern for a woman, whether or not she is sexually active. The medical term for a delayed or missed period is amenorrhea. Amenorrhea can be caused by a number of factors. Although in most cases the reasons for a late period are relatively benign, you should contact a doctor if you miss your period for more than three consecutive months.


If you are sexually active, pregnancy is the most common reason for delayed menstruation 1. Pregnancy is also a possibility if you have an extremely light period with pink or brown discharge that lasts only a day or two. Find out if you're pregnant by taking a home urine test, or have a urine or blood test at your doctor's office.

Birth Control Medication

Birth control pills, patches or injections can cause hormonal changes in your body that can make your period late or make your flow very light, especially if you've just begun using the medication. Stopping the use of birth control can also cause you to miss a period or have a late period because your body needs time to adjust to the change in hormones. If you are in the first cycle of the medication and you miss a period, or if you've just stopped using hormonal birth control, take a pregnancy test.

Another possibility for a missed period is that the hormones in the medication are causing your period to stop. This side effect in common in medications that contain little or no estrogen. If you miss more than one period after starting birth control and you're not pregnant, talk to your doctor.

Diet and Exercise

A sudden weight loss or weight gain can cause your period to be late. Obesity can change your menstrual cycle because the overabundance of fat cells can stop ovulation. Losing a lot of weight or being too thin can also make you stop ovulating, which is your body's response to malnutrition or the loss of body fat needed to carry a pregnancy.

Strenuous exercise, either overexercising or training heavily for an event, can interfere with ovulation as well. The extra stress on your body signals your body to prevent pregnancy as a way of protecting itself.


Stress and tension can cause your period to be late, usually because ovulation is delayed or missed. If your period is late, consider important life changes or significant events in your life over the last cycle. Major events can include moving, vacations, a new job, school exams, loss of a loved one or any other cause of ongoing anxiety.


The average age for the onset of menopause is 45. Menopause usually doesn't start all at once. Instead, periods become irregular and less frequent, often over the course of several years, before menstruation stops entirely. In some women, menopause can begin prematurely. Menopause is considered premature if it starts before the age of 40. Talk to your doctor if you suspect that you are menopausal.

Health Problems

In some cases, underlying health problems can be the cause of late or missed menstruation. Hormonal imbalances and endocrine problems can affect the menstrual cycle, as can ovarian cysts and fibroid tumors. Medications for health problems unrelated to reproduction can also cause your period to be late.