9 Reasons for a Late Period

What to Do When You Have a Missed Period

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Pregnancy is the first thing women think of when their period is delayed but is it the only reason for a late period? The answer is a resounding no. There are several factors that can influence the timing of your period. In many cases, simple changes to your everyday routine are to blame and being mindful of them can get your period back on track. In other cases, a visit to the doctor might help sort things out.

Here are nine common reasons your period may be delayed.

1) Stress

Sometimes we're so stressed out that our body decreases the amount of a hormone called GnRH, which causes us to not ovulate or menstruate. If you know that you're stressed—perhaps you're coping with a difficult situation, or have a lot going on at work or school—carve out some time to help you relax. Even small steps, like 5 minutes of meditation, a massage, or a short walk, can make a difference.

If you're experiencing prolonged stress and more than one missed period, work with your doctor to help you figure out what you need to do to relax and get back on schedule. Note that this issue can sometimes take a few months or more to work itself out, but once you have identified and relieved the stress, your cycles should return.

2) Illness

Both sudden, short illnesses and chronic conditions can cause your periods to be delayed. If you think this is the reason that your period is late, talk to your practitioner to help you pinpoint the condition, find an appropriate treatment, and then determine when your period is likely to return.

A few common conditions that affect cycles include an overactive thyroid and polycystic ovarian syndrome (PCOS). One unusual example is a pituitary tumor (it's very rare, but a missed period may be a symptom).

If you miss a few periods in a row and you see your healthcare provider, it is likely they will do a blood test and a full exam to help pinpoint what's going on in your body.

3) A Change in Schedule

Changing schedules can throw off your body clock. This is particularly true if you go from days to nights at work or vice versa. If you frequently change shifts and notice problems with regular cycles, talk to your provider for options on how to stimulate a regular feeling for your body.

4) Change in Medications

When your doctor changes or introduces a medication, ask about potential side effects. Some, like antidepressants, antipsychotics, thyroid, and some chemotherapy drugs, may cause your period to be absent or delayed.

Birth control (particularly progestin methods like Depo-Provera, progesterone only- minipill, Mirena IUD, and Nexplanon) can also influence your cycle.

5) Your Weight

Overweight, underweight, and drastic changes in weight all impact your cycle. Being overweight, for example, can cause hormone imbalances that influence your period. Most women will see a return to normal cycles and fertility with the loss of some weight, even if they are still considered overweight. The higher your body mass index (BMI), the greater the chance that you will miss periods.

On the flip side, if you do not have enough body fat you will not have regular periods; sometimes, that can even cause your periods to stop altogether. This is called amenorrhea. Typically a weight gain will help your periods to return. Being underweight is a frequent cause of a missed period in women who work out to an extreme or are professional athletes. Women diagnosed with anorexia may also have erratic periods.

6) Miscalculation

The menstrual cycle varies from woman to woman. While we say that the average menstrual cycle is 28 days long, that is not true for everyone. Sometimes you'll think your period is late but you've actually just miscalculated.

If you have irregular menstrual cycles but know when you ovulate, look for your period about two weeks after you ovulate. That may help you keep better track of your periods. Remember, a normal cycle length is between 21 and 35 days in healthy women.

7) Perimenopause

Perimenopause is the period of time where you are transitioning from reproductive age to non-reproductive age. Your periods may be lighter, heavier, more frequent, or less frequent. In most cases, they'll just be something different than what you're used to.

8) Menopause

Menopause is when you have reached the point in your life where you will no longer ovulate or menstruate. It's natural for all women. The average age of menopause is 51 years old.

9) Pregnancy

In some (but obviously not all) cases, your missed period might be because you're pregnant. A simple pregnancy test can usually help you determine if this is the case. Urine pregnancy tests and blood pregnancy tests look for the hormone hCG. As an extension of pregnancy, you may also notice that your first postpartum period may be delayed if you are breastfeeding.

When to Call Your Doctor Or Midwife

In the absence of pregnancy, missing a period or two, even when you suspect you know the reason, is something that needs to be investigated by your doctor. Together the two of you can get to the bottom of your delayed menstrual cycle. You may want to see a practitioner sooner if you experience any of the following:

  • Headaches
  • Hair loss
  • Vision changes
  • Breast secretions or milk production

A Note on Amenorrhea

Your doctor has several choices for diagnosing the cause of amenorrhea. A pregnancy test, even after you've already tried them at home, is usually the first step. Next is blood work. Here your doctor can get a full overview of what is going on in your body and measure hormone levels. You may be given a medication to take for seven to ten days to see if that brings on your tardy period. Other tests used will be determined by your health history and your previous test results.

How you treat amenorrhea is going to depend on why you aren't having your period. The treatment can be as simple as lifestyle changes (diet, exercise, stress reduction), or can include hormone replacement therapy. This is a decision between you and your doctor. If you are trying to get pregnant, be sure to let your practitioner know.

A Word From Verywell

There are many reasons for late periods. Many of the reasons only require some lifestyle changes to help address the underlying cause and bring your periods back to a normal schedule. When medical attention is needed, a professional can help you figure out why you aren't having periods and work to get your body into good health again.

View Article Sources
  • American College of Obstetricians and Gynecologists. Abnormal Uterine Bleeding. March 2017.
  • American College of Obstetricians and Gynecologists. Good Health Before Pregnancy: Preconception Care. March 2015. 
  • Burd, I. Absent Menstrual Periods - Secondary. 2016.
  • Mitchell A, Fantasia HC. Understanding the Effect of Obesity on Fertility Among Reproductive-Age Women. Nurs Womens Health. 2016 Aug-Sep;20(4):368-76. doi: 10.1016/j.nwh.2016.07.001. Review.
  • Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Sixth Edition.