Period in your 20s, 30s and 40s: What's normal & what to expect

Average Cycle Length

You’ve probably heard it said that 28 days is the average length of the menstrual cycle. But that’s not strictly true. The length of your menstrual cycle is counted from the first day of one period to the day before you get your next period – so cycles can vary wildly from person to person, depending on how often you get your period. 

So, then, what’s normal when it comes to cycle length? It’s all about what’s normal for you. Some people might have a menstrual cycle that lasts 20 days, while others have one that lasts for 30 days – and both fall within the range of what’s considered ‘normal’. Our research into the menstrual cycle found that just one in eight women have a 28-day cycle, and ‘normal’ can be anything between 21 and 35 days.

And what is a normal period? Well, when it comes to the period part of your menstrual cycle, that can also vary. A typical period lasts between two and seven days – but this can be different from person to person. Your period will typically last for a similar amount of time from month to month. Although it might vary slightly (you might bleed for four days one month and five the next, for example), you should keep an eye out for any significant changes to the length of your period. 

Changes in your period length can be cause for concern, but more commonly, it’s influenced by other factors, from medical conditions like polycystic ovary syndrome to whether you’re using hormonal birth control – and even what stage of life you’re at.

Your period in your 20s: Settling into your cycle

In the US, most people get their first period at around 12 years of age. Those first few years can be irregular while your hormones settle down – but by your 20s, most people’s periods have settled into a more regular rhythm. At this age, your cycle is probably between 21 and 35 days, with periods lasting 2 to 7 days.

You reach the peak of your fertility in your late teens, and this continues into your 20s. That means that your period is typically at its most regular during your 20s – even if you don’t plan on having children any time soon. 

Although you’re at your most fertile during this period, it doesn’t mean that you need to rush to get pregnant if you want children. For healthy couples in their 20s and early 30s, around 1 in 4 women will get pregnant in any single menstrual cycle. This declines to around 1 in 10 by age 40. If children are in your future, it’s just important that you’re aware of fertility rates at every stage of your life so you can better plan for the future.

Look out for changes in your cycle

For many people, their 20s are the time when they notice if they have any unusual symptoms as their cycle settles into a more regular groove. Unusual symptoms could include:

• A period that lasts longer than eight days
• Extremely heavy periods
• A particularly long or short cycle
• Any pain

If you have any of these, then it may be indicative of a condition like PCOS, endometriosis or fibroids. If you notice anything that’s not normal for you, it’s always best to get it checked out by your healthcare provider.

The impact of birth control

It can take a while to find the right type of birth control for you. Many people are dissatisfied with their birth control, so your 20s may be a good time to experiment with different types to find the right one for you. Birth control won’t affect your fertility in the long-run, but it’s important to remember that hormonal birth control can mask any unusual symptoms. 

If you have irregular periods or symptoms of conditions like PCOS and endometriosis, then hormonal birth control can reduce your symptoms – in fact, birth control is often prescribed to help with the pain and other symptoms caused by these conditions. Both endometriosis and PCOS can both affect fertility, so you might not notice that there are any issues until you come off birth control.

Your period in your 30s: A mixed experience

Your 30s can be thought of as a decade of two halves. In your early 30s, you can expect your period to be much the same as in your 20s, as it’s likely you’re still ovulating regularly – and therefore, your menstrual cycle should be roughly the same length.

In the second half of your 30s, your fertility starts to decline, with lower fertility typically occurring in your late 30s. Your fertility will continue to decrease every year, as the number of eggs you have and the quantity of good quality eggs decreases with age. That can lead to a more irregular menstrual cycle. Your cycle and period may both become shorter – and you may notice heavier bleeding when you get your period.

Of course, it’s important to note that while your fertility typically starts to decline in your late 30s, many women do manage to successfully conceive at this age – so there’s not necessarily any need to panic. If you’re planning a pregnancy, Natural Cycles can help you to find your fertile days to help you conceive faster.

Fertility and pregnancy planning

Most women who want to, and are able to, have children, will do so in their 30s. A recent study found that the median age for women giving birth in the USA is now 30, the highest ever on record. It’s a similar story across the pond, with a mean age of 30.7 in 2020 for women giving birth in England and Wales.

Of course, being pregnant means you won’t get a period for the duration of your pregnancy. It’s worth noting that some women do have some bleeding during early pregnancy, which is important to get checked out – but it isn’t always a cause for concern. 

It can take a while for your period to return after you give birth, but for most women, it does come back within a year. We conducted a survey of Natural Cycles users who had given birth in the last 6-24 months. We found that one in four Cyclers got their first period within three months after giving birth, half of the respondents got their period back within six months, and three in four women got their period back within a year of giving birth.

Your period in your 40s: A time for change

The majority of women experience perimenopause in their 40s. That’s because the most common age for menopause is 51, and perimenopause can happen for 4-8 years before reaching menopause.

Menopause is technically confirmed when you haven’t had a period for a full year. Those going through perimenopause may have all of the same symptoms as those experiencing menopause – but they also have periods, which may be irregular. Until you haven’t had a period for a year, menopause can’t be confirmed, so it’s termed perimenopause instead.

Perimenopause signs

Symptoms of perimenopause can include:

• Night sweats
• Vaginal dryness
• Hot flashes
• Reduced sex drive
• Mood changes
• Anxiety
• Headaches
• Difficulty sleeping
• Irregular periods
• Problems with memory and concentration

It varies for everyone – some people might experience all of these symptoms, while others might not have any. For some people, perimenopause kicks in months before menopause, while others experience symptoms for years before their periods stop. 

When it comes to cycle length, many women notice that their cycle becomes shorter as they get older – while the length of your periods may get longer or shorter.

The effects of birth control on perimenopause

If you’re using hormonal birth control, it can be difficult to know when symptoms of perimenopause or menopause begin, as it can affect your cycle. If you’re taking the combined pill, you’ll have monthly bleeds – which aren’t really periods, but are actually withdrawal bleeds – and you’ll have these for as long as you’re taking the pill.

Other types of hormonal birth control like the progestin-only pill, contraceptive implant and contraceptive injection may give you irregular bleeding, or no bleeding at all, so it can be difficult to tell if your periods are becoming more irregular. Some women also use hormonal birth control to regulate perimenopause symptoms, as low-dose hormonal birth control can help to reduce symptoms and ease the transition.

Pregnancy in your 40s

Even if you start experiencing symptoms of the perimenopause in your 40s, you can still get pregnant as long as you’re ovulating. But, as ovulation becomes less frequent, it can be harder to get pregnant. If you are hoping to have a child, you may want to track ovulation and look out for patterns in your cycle, to help you better plan when to try for pregnancy. Starting to track your cycle using the basal body temperature method when you’re younger can help you spot any patterns or issues when you are ready to get pregnant.

Menopause symptoms

The average age for menopause is 51 – but it can happen anywhere between the ages of 45 and 55. It’s rare for menopause to occur before the age of 40, but it does happen for 1 in 100 women. This is known as premature menopause.

The symptoms of menopause are similar to those of perimenopause, including hot flashes, night sweats, vaginal dryness, reduced sex drive and low mood – and, eventually, a stop to ovulation and your periods.

If you’re concerned about any menopausal symptoms, or you’re experiencing them before the age of 45, then you should seek help from a healthcare professional. They’ll be able to confirm if you’re perimenopausal or menopausal, and suggest ways to deal with your symptoms.

Irregular menstrual cycle and bleeding

As we’ve outlined, your cycle may be irregular at different stages of your life. It’s most likely to be regular in your 20s, when you’re at your most fertile, and then it may become more irregular as ovulation decreases and you get older.

Bleeding may also vary throughout your life. The length of your period should typically stay the same from month to month, so you should keep an eye out for any more significant changes to the length of your menstrual cycle or any irregular bleeding. These changes can be indicative of an underlying condition, or the start of a different phase of life, like perimenopause.

Remember, an irregular cycle or irregular bleeding isn’t always a cause for concern. It’s very common, for example, to have irregular bleeding with some hormonal methods of contraception. Stress can also cause changes in your cycle from time to time. So, it’s not always something to worry about – but tracking your cycle is always a good idea, to help you spot anything that is of concern.

What your period can tell you

We’ve established that there’s no such thing as a ‘normal’ period, as everyone is so different. What is important is to understand what’s normal for you – which is why tracking your cycle and keeping note of any symptoms, as well as any changes, can be helpful.

The color of your period blood can tell you a lot about the stage of your cycle and whether there are any underlying health concerns. For example:

• Brown period blood may indicate pregnancy
• Brown or dark red blood may be a symptom of perimenopause
• Pink blood may be the result of hormonal birth control
• Gray period blood can indicate an infection

Keeping track of your period and menstrual cycle symptoms with Natural Cycles can help you to learn more about your cycle – which is useful whether you’re trying to conceive or avoiding pregnancy. 

When to see a doctor

If you notice anything that’s unusual for you, then it’s a good idea to see your doctor. That could include:

• Irregular periods
• Periods that last for longer than 8 days
• Heavy bleeding
• A menstrual cycle that’s shorter than 20 days
• A menstrual cycle that’s longer than 35 days
• Symptoms of perimenopause or menopause
• Painful periods

If you’re tracking your periods, a doctor can use that information to diagnose medical conditions, or help you to manage your symptoms. They can also better understand whether you might have any fertility issues, which is especially important if you’re planning a pregnancy.

More than a period tracker

Natural Cycles is more than just a period tracker. We’re committed to providing a birth control option that’s not only hormone-free, but that also helps you to learn more about your menstrual cycle and reproductive health. Take the quiz to find out more about how Natural Cycles can support you.