10 Reasons Why You Missed Your Period

Did You Skip Your Monthly Cycle? One of These May Be the Reason

Woman looking concerned. Brad Wilson/Getty images

From puberty until menopause most women can expect to see their period every month. A normal menstrual cycle is between 21 and 35 days long. When it doesn’t come at its usual time most women who have regular periods notice right away. Understanding why you missed your period is important. Here are some possible reasons for your missed period.

1. You Are Pregnant

This is the most common reason why women of reproductive age miss their periods.

If you are having sex it is probable that the reason for your missed period is pregnancy. Even if you are using birth control it is important to consider this as the reason why your period didn’t come. Remember that no method of birth control other than abstinence is 100 percent effective in preventing pregnancy.

More importantly, certain types of birth control increase your risk of having an ectopic pregnancy, which is potentially a very dangerous diagnosis. The earlier you know that you are pregnant the better. A simple home pregnancy test can rule this out (or in) as the cause of your missed period.

2. You Are on Hormonal Contraception

Some types of hormonal contraception can cause amenorrhea or an absence of your menses. This is typical and a known side effect of the progestin methods like:

  • Depo Provera
  • Progesterone only- minipill
  • Mirena IUD
  • Nexplanon

However, sometimes women using a combined hormonal contraceptive can miss their period.

This can be done intentionally by adjusting how the method is used. But with typical use a missed period on the following hormonal birth control is not common:

  • Oral contraceptive
  • Contraceptive patch
  • Contraceptive ring

If a missed period does happen on one of these types of birth control it is usually on a low dose oral contraceptive pill.

3. You Started Training for a Marathon

A significant increase in your physical activity level can suppress your ovulation and this in turn will cause you to miss your period. When you do not ovulate the hormonal changes that result in your menstruation do not occur.

4. You Are Studying for Exams

Lack of sleep, poor diet, worrying about your final grades takes a toll on your body. Any situation that causes a significant amount of psychological stress can also suppress your ovulation and stop your period.

5. You Have Recently Lost or Gained Weight

Changes in your body mass index (BMI) can also affect your ovulation. Either a very low BMI or a BMI in the obesity range can cause you to miss your period.

6. You Started a New Medication

Certain types of medication, especially psychiatric drugs, can suppress your ovulation, leading to a missed period. Be sure to ask about the potential side effects of any new medication you are prescribed.

7. You Have an Overactive Thyroid

Your thyroid is an endocrine gland that produces hormones that help to regulate your metabolism. When your thyroid is too active a condition called hyperthyroidism it can also suppress your bodies ability to ovulate and therefore menstruate.

8. You Have a Pituitary Tumor

This is a pretty rare cause of a missed period. If you miss a few periods in a row and you see your healthcare provider it is likely they will do a blood test to screen you for a pituitary tumor. Other symptoms of this type of tumor are a headache and blurry vision.

9. You Have Premature Ovarian Failure

This is a rather uncommon cause of missed periods. Premature ovarian failure causes menopause before age 40. Along with a lack of periods, you may experience some of the other symptoms of menopause such as night sweats, hot flashes, irritable moods, or increased anxiety.

If you have type 1 diabetes you may have an increased risk of premature ovarian failure.

10. You Have an Ovarian Hormone Imbalance

The cause of your missed periods may be due to the ovarian hormone imbalance called polycystic ovarian syndrome or PCOS.  This condition results from an excess of progestin production by the ovary that leads to hormonal imbalances that inhibit ovulation. These hormonal imbalances also can cause acne and excess hair growth. Women with this condition may also be obese and have insulin resistance or even type 2 diabetes.

In general, unless you are pregnant, one missed menstrual cycle is typically not a cause for concern. However, if you miss three periods in a row or if you have other symptoms that are bothersome your healthcare provider will likely recommend some testing.

As always you should discuss any changes in your menstrual cycle with your healthcare provider.


Absent menstrual periods - secondary. MedlinePlus. https://medlineplus.gov/ency/article/001219.htm. Updated 5/16/2016.

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