What’s a normal menstrual cycle?

The menstrual cycle by FUTURE WOMAN

One of the most common questions we get asked at FUTURE WOMAN is “is my menstrual cycle normal?” 

In this article we cover the 12 most common questions we hear from clients about the menstrual cycle, from cycle length and ovulation to heavy, light or painful periods.

First of all, What can our menstrual cycle tell us?

You might be surprised to know that your menstrual cycle offers vital information about your overall health. In fact, the American College of Obstetrics and Gynaecology advises health practitioners to consider periods the “fifth vital sign”. That means they consider menstrual health to be as valuable an indicator of overall health as our heart rate, respiratory rate, blood pressure and temperature!

By tracking your menstrual cycle carefully you can understand if you’re ovulating, what kind of hormone imbalances you may be struggling with and how your diet and lifestyle are affecting you.

So let’s dive into the 12 most common questions we get asked by clients around a normal menstrual cycle and what to do if yours is off balance.

1. What's a normal menstrual cycle length?

A normal cycle length is anywhere between 21 and 35 days. Interestingly only around 10-15% of women actually have a 28 day cycle. In fact, recent research has shown that the mean cycle length for adult women is 29.3 days.

Cycles shorter than 21 days could be an indication of low progesterone or a short luteal phase. This could be due to factors such as lack of ovulation, stress, over-exercise, undereating or a thyroid imbalance. In fact many women with a cycle close to 21 days often have a shorter luteal phase (second half of their cycle) which can cause difficulties with fertility.  

Cycles longer than 35 days could be a sign of PCOS due to lack of ovulation, high luteinising hormone and high testosterone or perimenopause due to low progesterone. 

If your cycle is outside the normal range, testing your hormones can help you understand which hormonal imbalances are driving your shorter or longer cycles.

Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles
A 2019 study based on 600,000 women concluded that the mean cycle length was 29.3 days.

2. What’s a normal amount of variation between menstrual cycles?

A regular cycle is considered to be consistently the same length, give or take a couple of days. Natural fluctuations in a cycle are normal, so if your cycle is 31 days one month, and 35 days the next month, that’s still considered a regular cycle. 

The general rule is that the length of your menstrual cycle can vary up to 8 days in a year. This means one cycle may be 30 days, another 28 and another 35. This would mean there was a variation of 7 days (between the shortest 28 and longest 35). 

Irregular cycles are a hallmark of PCOS. Learn more about testing with PCOS.

What's normal In adolescence?

When you first start your menstrual cycle the first few years are likely to be irregular and this is normal. Your periods may also be heavier during this time as well. But it is important to remember that this is normal. 

What's normal in perimenopause?

In perimenopause your ‘normal’ might begin to change. Cycles might become shorter but periods might be heavier and more painful due to the drop in progesterone and sporadic ovulation. 

It is normal for cycle lengths to change in perimenopause but if you are suffering from increased painful periods, heavy periods or other new symptoms like poor sleep, weight gain, anxiety and brain fog then it is worth investigating and testing to understand what may be influencing this. Read more about testing with perimenopause.

3. Is it normal to have a missing period?

A missing period is common, but not normal, so if your period has gone missing it’s important to understand the root cause. 

First and foremost, it’s important to rule out pregnancy, even if you are on birth control such as the oral contraceptive pill or IUD. If pregnancy, has been ruled out, then other possible causes of a missing period include PCOS, stress (from things like illness, travel as well as relationship and work stress), weight changes and hypothalamic amenorrhea, perimenopause and thyroid imbalances.

Read more about the 5 causes of missing periods and what to do about them.    

4. What is considered heavy bleeding?

Your period is considered to be heavy if you are bleeding more than 80ml per period. This can be equated to 16 regular tampons across your period. 

Heavy bleeding could be a sign of high, unopposed estrogen or poor estrogen metabolism. We recommend testing your overall estrogen levels, your estrogen levels relative to progesterone and your phase 1 and phase 2 estrogen metabolites to see what’s driving your heavy periods.

Read more about estrogen metabolism.

5. Am I bleeding for too long?

It is considered normal to bleed for 2-7 days. But your period should have a start, a middle and an ending. This means if you are bleeding constantly heavily for 7 days this is considered too long. 

Like heavy bleeding, bleeding for too long could also be a sign of high, unopposed estrogen or poor estrogen metabolism and testing your hormones can help you understand which hormonal imbalance driving of your symptoms.

6. Is my period too light?

If you are bleeding for less than 2 days or are barely filling a panty liner with blood then it is likely your periods are too light. 

This can be due to a number of different factors including low estrogen levels, lack of ovulation and stress. Testing your overall estrogen levels, progesterone and cortisol can help you get to the bottom of your light periods. 

£249

  • Comprehensive hormone and metabolites test.
  • Expert-reviewed report with your results.
  • Personalised diet and supplement protocol.

7. Is it normal to spot?

It can be normal to have a day of spotting in advance of your period and even at the end. But if you are spotting for more than a day it could be a sign of low progesterone. 

Progesterone is important for fertility, but this super hormone also supports our sleep, mood, and breast health! We test progesterone with our at-home hormone tests. In fact, we specifically test in the middle of your luteal phase so that we can get an accurate progesterone reading.

It’s important to note, if you are spotting at other times in your cycle you should check this with your GP. 

8. Is it normal to experience period pain or menstrual cramps?

Painful periods impact nearly all women at some stage in their lives. But although they may be common they are not normal. 

Typically period pains are worse in puberty and again during perimenopause due to the hormonal fluctuations and a tendency towards higher estrogen and lower progesterone at these times. It can also be due to poor estrogen metabolism.

Read more here about other causes of painful periods and how you can help them

9. Does having a regular cycle always mean ovulation has occurred?

No, not necessarily. In a recent series of studies, lack of ovulation (or anovulation) was found to occur about 10-18% of the time in women. This can be due to factors such as low estrogen levels, stress, under eating and over exercising. In fact, in mature women, stress is more likely to result in missed ovulation than a missing period.

Ovulation takes place roughly in the middle of your cycle, and involves the release of an egg to prepare for fertilisation and pregnancy. 

In a healthy menstrual cycle, we believe ovulation is actually the main event rather than your period. And ovulation is not only important for pregnancy! Progesterone, our wonder hormone, is only made as a result of ovulation. Progesterone supports healthy sleep, mood, memory, cognition, skin and more. 

10. How can I tell if I'm ovulating every cycle?

We believe tracking your ovulation is a game changer for your hormonal health and we encourage ALL our clients to track ovulation. 

You can track ovulation by monitoring your basal body temperature on waking and the colour and consistency of your cervical mucus. For more information on how to do this, sign up to our newsletter and receive our FREE cycle tracking guide! 

If you suspect you aren’t ovulating, then it’s important to test to understand why. We would look at your overall estrogen (you need sufficient estrogen levels for ovulation to occur), cortisol (to see if stress is a contributing factor) and also we’d look for certain nutrient deficiencies like B6 (B6 helps with progesterone production and supports the luteal phase of your cycle).

£349

  • Comprehensive sex and adrenal hormone and hormone metabolites test.
  • Expert-reviewed report with your results.
  • Personalised diet and supplement protocol.

11. What is a normal follicular phase length?

The follicular phase is the first part of your cycle from the first day of your period to ovulation. The length of your follicular phase can change easily as it can be easily influenced by stress, diet, sleep and more. 

Typically in a 28 day cycle, the follicular phase is around 14 days long.

If you are experiencing a longer follicular phase then it may suggest that you have low estrogen and may not be ovulating. If you have a shorter follicular phase it may suggest you are in perimenopause and a shorter follicular phase can impact your ability to get pregnant, therefore testing can be very beneficial here.  

12. What is a normal luteal phase length?

The luteal phase is more fixed in length than the follicular phase. The luteal phase is from ovulation to the first day of your period again. Typically on average a person’s luteal phase is 12-14 days long but can be as long as 10-16 days. 

The length of your luteal phase is an important indicator of your overall progesterone levels, especially if you are trying to get pregnant but also for the health benefits that progesterone has to offer the body such as lighter periods, improved sleep and boosted mood.

A luteal phase shorter than 10 days is usually a sign of low progesterone. This could be due to factors such as lack of ovulation, stress, over-exercise, under eating or a thyroid imbalance. A shorter luteal phase is also a common hallmark of early perimenopause as ovulation becomes more sporadic.

If you’re noticing a shorter luteal phase, we’d recommend testing estrogen, progesterone and also other markers like cortisol (to see if stress is a contributing factor).

Key takeaways

If you are experiencing long cycles, heavy periods, painful periods, very short cycles or are experiencing any changes from your regular cycles then it is important to test your hormones to understand the key drivers. 

Testing your hormones can help get to the root cause of what’s driving your cycle irregularities, and from there our practitioners can create personalised and targeted protocols to help you achieve a regular and normal period. 

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