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Is this normal? Your period in your 20s, 30s and 40s

  • A typical period cycle is 28 days.
  • Menstruation typically lasts two to seven days.

In the United States, the average age of a woman's first period is 12.3 years old, which means most women have menstrual cycles a significant portion of their lives. Because of this, some of the most common questions I'm asked are about periods and what is considered "normal." Here is what the average woman can expect to experience. 

In your 20s and early- to mid-30s

Your period should have become regular and predictable by this time. The average cycle lasts 28 days when counting from the first day of one cycle to the first day of the next cycle. Eighty percent of cycles occur within 21 to 45 days. Typically, cycles will last two to seven days. 

Be sure to watch for the following:

  • heavy flow (need to change a pad or tampon pad every one to two hours) or abnormal bleeding that last more than seven days
  • cycles less than 21 days or longer than 38 days
  • bleeding between cycles or after intercourse  
  • missed periods, as this could be an early sign of pregnancy or may be caused by polycystic ovary syndrome (PCOS), especially if missed periods are accompanied by excess hair growth, weight gain and high cholesterol.

Some abnormalities during the reproductive years might include polyps, fibroids as well as anovulation (lack of ovulation), endometriosis (growth of endometrial tissue outside the uterus) and—less common—tumors/growths. Bleeding can also be a symptom of infection such as endometritis (infection of the inner lining of the uterus) or pelvic inflammatory disease.   

Remember, not all bleeding and irregularity is a cause for concern. For example, it is very common to have irregular bleeding with some contraception methods. Stress and other issues can also cause changes to your cycle from time to time.

Also, many women in the 20s and 30s experience painful menstrual cramps. You can treat cramps with over-the-counter pain relievers or heating pads.

In your late-30s and 40s

The average age of menopause (12 months of no cycles) is 51 to 52. However, menopause can occur earlier for some women. During the 10 years before menopause, many women often experience changes to their cycles. 

Women in their late-30s and 40s tend to have shorter cycles with heavier bleeding. They may also have intermittent menopausal symptoms such as hot flashes and night sweats. During this time, you can also expect some variation in the number of days of bleeding or the amount of flow. Some cycles may be skipped and then followed by a heavy cycle. 

Watch for the same issues as above, but also pay attention to:

  • heavy bleeding that is accompanied by dry skin, hair loss and a slow metabolism, as this could signify thyroid issues
  • bleeding between cycles or after intercourse.

Remember, you know your body best. If something doesn't feel right to you, contact your provider to determine the right course of action. Seeing your provider for an annual physical is a great opportunity for you to talk about any cycle and body changes.


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