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Does your menstrual cycle change with age?

Does your menstrual cycle change with age?

Your menstrual cycle changes markedly throughout your life, for important reasons. With adolescence comes puberty and your first period, followed by your most fertile years: your late teens through your 20s. Here’s how your cycle may change decade by decade, including in your teens, 20s, 30s and 40s, and during perimenopause and menopause. Knowing the approximate timing for these milestone changes can help you make crucial decisions related to your reproductive health. 

How your menstrual cycle changes throughout your life


  • Peak fertility continues through late 20s3
  • Regular menstrual cycle lasts anywhere from 23 to 35 days4


  • Fertility starts to decline, more rapidly in mid 30s3
  • Regular menstrual cycle lasts anywhere from 23 to 35 days4
  • PMS may worsen6
  • Uterine fibroids and endometriosis are more common7


  • Fertility continues to decline3
  • Perimenopause typically begins in mid to late 40s8
  • Menstrual cycle may change8


  • Menopause typically happens around age 519
  • Pregnancy is no longer possible once menopause occurs10

Your first period and your menstrual cycle during your teens

First periods happen during puberty, about two years after breasts start to develop, typically around age 12. (If you get your first period earlier or later, that’s normal, too.1,2) First periods are often light and last two to seven days.1 For teenagers, any menstrual cycle that lasts 21 to 45 days is considered normal.1 It may take several years before a teenager’s menstrual cycle becomes regular.1,2

Changes in your menstrual cycle after 20

By your 20s, your menstrual cycle begins to find its groove. However, most women in this age group don’t have periods that appear every 28 days like clockwork. A regular menstrual cycle can last anywhere from 23 to 35 days,4 with your period generally lasting three to seven days within that span of time. Once you reach your 20s, a cycle that lasts more than 38 days or fewer than 24 days, or a period length that varies more than seven to nine days month to month, it may be considered irregular.5

According to the American College of Obstetricians and Gynecologists (ACOG), peak fertility begins in your late teens and continues until your late 20s.3 Depending on what’s happening in your life at this time, you may start — or stop — using contraceptives. 

According to the CDC, 61.9% of women use some form of contraceptive in their 20s; 19.5% use oral contraceptive pills and 13.1% use long-acting reversible contraceptives (LARCs) such as IUDs.11 Many women experience changes in their bleeding patterns due to hormonal contraceptives, including heavier or longer periods, irregular bleeding or breakthrough bleeding. They also may not have periods at all.12

Changes in your menstrual cycle after 30

In your 30s, you can continue to expect regular menstrual cycles lasting 23 to 35 days,4 with a period generally lasting three to seven days within that span of time. Just like in your 20s, be mindful of a cycle that is longer than 38 days or shorter than 24 days, or a period length that varies more than seven to nine days month to month.5

According to the CDC, 72% of women use some form of contraceptive in their 30s; usage of the pill drops by almost half, to 11%, compared to women in their 20s, and usage of LARCs drops to 11.7%.11 This could be because women age 30 to 34 currently have the highest birth rate in the US.13 It’s important to note that fertility starts to decline in your 30s and rapidly declines from your mid-30s.3

Pregnancy can also affect your menstrual cycle. If you breastfeed, your period may not start again until you begin weaning. If you don’t breastfeed, or do a combination of breastfeeding and bottle feeding, your period could start within five to six weeks after giving birth.14 Menstrual cycles after pregnancy can be irregular, and you may experience more cramping, small clots and heavier periods than you’re used to.14

Premenstrual syndrome (PMS) may worsen as you reach your late 30s.6 Also, women in their 30s are more likely to have uterine fibroids, which can cause heavy and painful periods that last longer and are more frequent.7 Endometriosis, which affects one in 10 women, can cause heavy, painful periods and can take years to diagnose. Therefore, women may not be diagnosed until they are in their 30s and 40s.15

Changes in your menstrual cycle after 40

According to ACOG, by age 40, around one in 10 women will get pregnant per menstrual cycle (compared to around one in four women for healthy couples in their 20s and early 30s).3 Most women experience perimenopause in their mid-to-late 40s, at a time when they’re still ovulating.8 Your ovaries begin to make less estrogen during perimenopause and may not release an egg every month.8 This means it is possible to get pregnant during perimenopause, but fertility is now in a sharp decline3 and menopause is just around the corner. Perimenopause can last anywhere from a few months to more than 10 years.

Some women notice their menstrual cycle getting shorter with age. According to ACOG, changes in your menstrual cycle during perimenopause are normal. Your periods may become shorter or longer, and the days between your periods may increase or decrease. Your menstrual flow may become heavier or lighter. You also may begin to skip periods.8

Changes in your menstrual cycle after 50

Menopause occurs when your ovaries stop making estrogen and is confirmed when you haven’t had a period for 12 consecutive months (on average around age 51).14 Pregnancy is not possible once menopause occurs.10

If you experience bleeding after menopause, see your healthcare provider right away. Possible causes include side effects from certain medications, an infection in the uterus or cervix, or cancer.8

No matter what stage you’re in, knowing the menstrual cycle changes to expect can help you make important reproductive health decisions, and Clearblue® is with you along the way.




  1. “Your First Period,” (February 2019), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/your-first-period.
  2. “All About Periods,” (October 2018), TeensHealth, The Nemours Foundation, https://kidshealth.org/en/teens/menstruation.html.
  3. Have a Baby After 35: How Aging Affects Fertility and Pregnancy,” (October 2020), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy.https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy.
  4. I. Soumpasis, B. Grace, S. Johnson, “Real-life insights on menstrual cycles and ovulation using big data,” (April 16, 2020), Human Reproduction Open, 1-9, https://academic.oup.com/hropen/article/2020/2/hoaa011/5820371.
  5. “Abnormal Uterine Bleeding,” (December 2021), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/abnormal-uterine-bleeding.
  6. “Premenstrual syndrome (PMS),” (March 16, 2018), Office on Women’s Health, U.S. Department of Health & Human Services, https://www.womenshealth.gov/menstrual-cycle/premenstrual-syndrome.
  7. “Uterine Fibroids,” (June 2020), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/uterine-fibroids.
  8. “Perimenopausal Bleeding and Bleeding After Menopause,” (October 2020), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/perimenopausal-bleeding-and-bleeding-after-menopause.
  9. “Menopause FAQs: Understanding the Symptoms,” (n.d.), The North American Menopause Society, http://www.menopause.org/for-women/expert-answers-to-frequently-asked-questions-about-menopause/menopause-faqs-understanding-the-symptoms.
  10. “The Menopause Years,” (July 2020), The American College of Obstetricians and Gynecologists, https://www.acog.org/womens-health/faqs/the-menopause-years.
  11. Daniels K, Abma JC. Current contraceptive status among women aged 15–49: United States, 2015–2017. NCHS Data Brief, no 327. Hyattsville, MD: National Center for Health Statistics. 2018, https://www.cdc.gov/nchs/products/databriefs/db327.htm.
  12. “Birth Control,” (June 18, 2021), U.S. Food & Drug Administration, https://www.fda.gov/consumers/free-publications-women/birth-control.
  13. Hamilton, B.E., Martin, J.A., Osterman, M.J.K., “Births: Provisional Data for 2020,” (May 2021), National Center for Health Statistics, National Vital Statistics, Natality, https://www.cdc.gov/nchs/data/vsrr/vsrr012-508.pdf.
  14. “When will my periods start again after pregnancy?” (April 24, 2021), National Health Service, https://www.nhs.uk/common-health-questions/pregnancy/when-will-my-periods-start-again-after-pregnancy/.
  15. “Endometriosis,” (February 2021), The American College of Obstetricians and Gynecologists,” https://www.acog.org/womens-health/faqs/endometriosis.

7 questions about your period you’ve never dared to ask

Chances are that you learned the basics about your period sometime ago but not what you really want to know. And what you really want to know, you may be too embarrassed to ask.
Rest assured, you’re not the only one and we've got answers to seven (perfectly normal) period-related questions.