Period Changes Through the Decades: What's Normal?

Does your menstrual cycle change with age?

Your period changes 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. And the changes continue through your life, including into your 30s and 40s, and during perimenopause and menopause. So how often do period cycles change? Do periods get worse as you get older? And when should you see a healthcare provider? Knowing the approximate timing and reasons for these period changes can help you make crucial decisions related to your reproductive health.

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 young women get their 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 period becomes regular.^1,2

Period changes in your 20s — what’s “typical” & common shifts

How does your period change in your 20s?

By your 20s, your menstrual cycle usually begins to find its groove. A regular menstrual cycle can range anywhere from 21 to 35 days,³ with your period generally lasting three to seven days within that span of time. Once you reach your 20s, a cycle may be considered irregular if it lasts more than 35 days or fewer than 21 days, or if period length varies more than seven to nine days month to month.⁴

^{Can your cycle change after stopping birth control?}

It’s likely your period could change when you start — or stop — birth control. According to the American College of Obstetricians and Gynecologists (ACOG), peak fertility begins in your late teens and continues until your late 20s.⁵ And per the Centers for Disease Control (CDC), a study conducted between 2015-2017 found that 61.9% of women used some form of contraception in their 20s; 19.5% used oral contraceptive pills and 13.1% used long-acting reversible contraceptives (LARCs) such as IUDs.⁶

Many women experience changes in their bleeding patterns due to hormonal contraceptives, including heavier or longer bleeding, irregular bleeding or breakthrough bleeding. They also may not have periods at all.⁷

Period changes in your 30s — postpartum and early cycle changes

How does your period change in your 30s?

In your 30s, you can continue to expect regular menstrual cycles lasting 23 to 35 days,³ with a period generally spanning 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.⁴

How does pregnancy affect your period?

According to the CDC, 72% of women use some form of contraception 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%.6 This could be because as of 2020, women age 30 to 34 currently have the highest birth rate in the U.S. It’s important to note that fertility starts to decrease in your 30s and rapidly declines from your mid-30s.⁵

Pregnancy can also affect your menstrual cycle. If you breastfeed, your period may not return until you begin weaning. If you’re not breastfeeding, or you do a combination of breastfeeding and bottle feeding, your period could start within six to eight weeks after giving birth.⁹ Menstrual cycles after pregnancy can be irregular, and you may experience more cramping, small clots and heavier periods than you’re used to.⁹

Do periods get worse as you get older?

Premenstrual syndrome (PMS) symptoms may intensify as you approach your late 30s.¹⁰ 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.¹¹ Endometriosis, which affects one in 10 women, can cause heavy, painful periods and can take years to diagnose, meaning women may not be diagnosed until they are in their 30s and 40s.¹²

Period changes in your 40s — perimenopause changes

What’s the difference between irregular periods vs. perimenopause?

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).⁵ Most women experience perimenopause in their mid-to-late 40s, at a time when they’re still ovulating.¹³ Your ovaries begin to make less estrogen during perimenopause and may not release an egg every month.13 This means it is possible to get pregnant during perimenopause, but fertility is now in a sharp decline⁵ and menopause is just around the corner. Perimenopause can last anywhere from a few months to more than 10 years.

Do periods get shorter in your 40s?

Some women notice their menstrual cycle getting shorter with age. According to ACOG, period changes 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.¹³

Period changes in your 50s — late perimenopause to menopause

Do periods get lighter in your 50s? Or do they stop altogether?

Periods may become heavier, lighter or more sporadic during late perimenopause.¹³ 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).¹⁴Pregnancy is not possible once menopause occurs.¹⁴

When should I see a doctor about cycle changes and menopause?

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.¹³

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

FAQ

Period changes through the decades at a glance

Teens

• First period typically occurs around age 12^1,2
• Peak fertility begins in late teens⁵

20s

• Peak fertility continues through late 20s⁵
• Regular menstrual cycle lasts anywhere from 21 to 35 days³

30s

• Fertility starts to decline, more rapidly in mid 30s⁵
• Regular menstrual cycle lasts anywhere from 21 to 35 days³
• PMS may worsen⁶
• Uterine fibroids and endometriosis are more common^11,12

40s

• Fertility continues to decline⁵
• Perimenopause typically begins in mid to late 40s¹³
• Menstrual cycle may change¹³

50s

• Menopause typically happens around age 51¹⁴
• Pregnancy is no longer possible once menopause occurs¹⁴

Tools and related reading

• How long is a menstrual cycle?
• 7 questions about your period you’ve always wondered about
• How to track your menstrual cycle and ovulation
• Chances of pregnancy after 35