Follicular Phase (Menstrual Cycle) : How to understand & calculate it

Feb 7, 2021 | Menstrual cycle

For many women, the follicular phase (menstrual cycle) is such a mystery – probably just like the other ones.

If that’s you, don’t worry. In this blog post, you’ll find everything you should know about it.

Make sure to also check my blog post about the luteal phase which happens between ovulation and your periods. I go through how to calculate it and optimize it to reduce PMS and period discomfort.

What is the follicular phase?

The follicular phase of the menstrual cycle starts on the first day of your period (Day 1).

It ends as soon as ovulation starts, so it lasts between 10 and 25 days, depending on every cycle.

This phase includes periods and pre-ovulation.

Short follicular phases (less than 10 days) are often linked to age. So it’s normal for a +35-year-old woman to have a short follicular phase because of hormonal change.

Yet, it’s more problematic for younger women since it reduces the chances of conceiving.

Long follicular phases (more than 25 days) are a sign that more time is needed to ovulate.

That can happen when taking the pill for a long time (1) or in case of a vitamin D deficiency (2).

How does the follicular phase affect my body and mental clarity?

1. Periods

There’s nothing new in telling you that the first part of the follicular phase can be tough to handle for some women.

Menstrual cramps can be the result of a hormonal imbalance, gynecological issues, or an unhealthy lifestyle. 

In my blog post about the 4 phases of the cycle, I say that menstruations are related to the winter season.

Since estrogen levels are low, we lack energy and aren’t in a good mood.

So if you tend to withdraw into yourself, it’s completely normal.

4 phases of the menstrual cycle

2. Pre-ovulation

Once periods are over, estrogen levels start to rise again. That’s when you’ll find your energy back and  find yourself being more social again. Which is normal since your body is getting ready to ovulate… nothing’s left to chance lol.

That is also a time you’ll feel super productive, have a good memory and focus.

But, if the opposite happens and you feel fatigued, you might have an iron deficiency.

How to calculate the follicular phase?

You may already know that your temperature and cervical mucus fluctuate throughout your cycle.

Following these fluctuations will enable you to find when the different phases happen.

1. Temperature and cervical mucus

During the follicular phase, the basal temperature is pretty low and stable – around 36°C to 36.40°C.

Cervical mucus has a creamy appearance or is nonexistent. That will prevent sperm from entering the uterus.

Changes in these two variables will help you define the beginning of ovulation – and, thus, the end of the follicular phase.

2. Determine ovulation

What do these two changes look like?

When you start ovulating, your cervical mucus becomes more elastic and runny – we often talk about egg white texture. That will allow the sperm to pass: the coast is clear!

Yet, the temperature doesn’t go through noticeable changes.

It’s only when the ovulation is over that the temperature will rise and stay up there until the end of the cycle.

So it’s impossible to know beforehand when the follicular phase will end. Same for ovulation.

That’s why the cycle tracking apps that predict when you’ll be fertile aren’t 100% accurate.

Going back to the follicular phase, it’s impossible to know precisely when it will end. It’s instead a retrospective observation and estimation to do once ovulation is over.

Does the follicular phase always happen at the same time?

The duration of each phase can vary from cycle to cycle. Yes, even if your cycle is regular.

This is because your cycle is sensitive to many external factors: your diet, stress levels, mental health, etc.

You get it, even if many things said about the cycle are wrong (as ovulation happens on day 14 or a healthy cycle lasts 28 days), everybody is different.

The best thing you could do is to get to learn your cycle.

I use the fertility awareness method to track my cycle and monitor my fertility. If you want to learn about the method, I highly recommend you checking the best seller “Taking Charge of Your Fertility“.


follicular phase

Can I get pregnant during the follicular phase?


Even though fertilization only happens during ovulation, here’s something important you should know.

Sperm can survive up to 5 days in a woman’s body. Having unprotected sex at the end of the follicular phase can thus lead to a pregnancy.

Women who have a short cycle and follicular phase could even get pregnant when menstruating.

How can I improve the first part of my cycle?

If you read my previous posts, you already know that I swear by nutrition and holistic health to optimize your menstrual cycle.

And since the follicular phase is one of the tougher to go through (hello periods) there’s some work to do.

1. Watch your nutrition

During this phase, your body goes through a lot of inflammation.

That’s why it’s super important to favor anti-inflammatory foods. They will help you relieve your cramps and reduce bloating.

When on your periods:

  • Focus on magnesium-rich foods to help relax the muscles (dark chocolate, green veggies, whole grains)
  • Eat foods that contain omega-3s to help reduce inflammation (fatty fish, nuts, avocado)
  • Include foods rich in iron to counteract blood loss (spinach, eggs, pumpkin seeds)
  • To help iron absorption, include foods rich in vitamin C in your diet (oranges, bell peppers, cauliflower)
  • Limit stimulants and inflammatory foods/beverages (dairy, alcohol, coffee, refined sugar)
follicular phase

After your periods:

  • Focus on fiber to drop excess estrogen (legumes, fruits, whole grains)
  • Consume rich in zinc foods to contribute to the formation of a healthy egg (nuts, shellfish, eggs)
  • To keep a hormone balanced, eat foods that contain lignans (flaxseed, soy) and indole-3-carbinol (broccoli, radish, cabbage)

Find more on how to eat for each phase of your cycle in this article.

2. Manage your stress

Stress, whether it is mental or physical, has a huge impact on our cycle. During your periods, make sure to avoid as many stressful situations as you can.

When possible, plan your oral presentations and important meetings outside of this period and delegate as much as you can.

If you know your periods are coming soon, you may want to batch cook or clean the house beforehand.

This will prevent you from having too many things to do when they arrive.

Once they end and once you’ll get your energy back, you’ll be in your top form to start new projects, see people and go back to your go-go-go routine.

3. Take time for yourself

Having your periods is a perfect time (and excuse) to slow down and take a break.

It’s also the best time to work on yourself and consider the start of your cycle as the beginning of a new month.

Did you learn new things about the follicular phase (menstrual cycle)? If you have questions, make sure to leave them in the comments below so I can get back to you!

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my name’s Virginia

I’m on a mission to help women understand, trust & love their body🦋 

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