The follicular phase: everything you need to know about this period of the menstrual cycle

Many women are unaware of their menstrual cycle and how it works. However, knowing and understanding your body, how it works and how your mood fluctuates over the course of the month, for example, can be very useful. Focus on the follicular phase!


What is the follicular phase?

The menstrual cycle is composed of four phases: 

  • The menstrual phase or periods ;
  • The follicular phase;
  • Ovulation;
  • The luteal phase.

The average cycle length is 28 days. This is an average, as some women have longer or shorter cycles.

The menstrual cycle always begins on the first day of periods. This is the first part, and the least pleasant for many. On average, they last between 3 and 7 days, and here again, every woman is different. Blood flow varies according to the day of the periods and the nature of each woman.

After the periods, comes the follicular phase. During this phase, which lasts around 14 days (from the first day of periods), the ovarian follicle takes over. What is the ovarian follicle? It's like a little bag in which ltheoocyte (also known as the gamete) has been stored since birth. 

The ovaries contain a stock of 500,000 follicles. All these follicles have one thing in common: they want to provide the next oocyte. During this phase, the oocyte prepares to leave the ovary and become an egg. The oocyte then travels through the fallopian tubes to the uterus, where it may meet a spermatozoon. If fertilization does not occur, it will be expelled during the next periods.  

During the follicular phase, also known as the pre-ovulatory phase, hormones change. Estrogen increases, which will :

  • Thicken the endometrium (uterine lining);
  • Maturation of the ovarian follicle;
  • Modify cervical mucus to make it more translucent and less thick, to facilitate the passage of spermatozoa.

After the follicular phase comes the ovulatory phase. On average, this marks half the cycle. This is when the egg is released into one of the two fallopian tubes. This phase is very short, lasting just one day.

Finally, the last phase of the female cycle is the luteal phase. At the start of this phase, the uterus prepares to receive the egg if fertilization takes place. SIf there is no meeting between egg and spermatozoon, hormones will drop, causing the menstrual flow to evacuate the uterine lining. 

What happens in the body during the follicular phase?

The follicular phase is not just about oocyte growth: there are many other changes involved.

During this phase, or folliculogenesis maturation stage, certain gametogenic follicles are activated to grow and mature. They evolve over a period of 14 days, passing through several stages:

  • First, dozens of primordial follicles develop into primary, then secondary (also called antral) and tertiary (cavitary) follicles;
  • But only one of these follicles will be able to detach from the others to continue its maturation. When this follicle detaches from the others, it reaches the stage of pre-ovulatory follicle or de Graaf follicle or mature follicle;
  • It is this follicle that will release an oocyte when it reaches maturity at the moment of ovulation.

This stage of the cycle is controlled by theFSH hormone secreted by the pituitary gland. While the ovarian follicles and oocyte are working, the uterus is also getting ready: under the action of the estrogens secreted by the ovary, the endometrium (or uterine mucous membrane) fills with blood to thicken and be ready to receive an egg.

Cervical mucus also undergoes changes during the follicular phase: after menstruation, the mucus is rather thick and opaque, with no discharge. At the end of your follicular phase, however, you may notice a change in the lappearance of the cervical mucus: it becomes more translucent, but also more liquid, making it easier for sperm to pass through.

What are the symptoms of the follicular phase?

At the start of the follicular phase (i.e. menstrual flow), some people may experience symptoms of varying severity. These may include menstrual pain and menstrual crampsbut also psychological symptoms such as moodiness, fatigue...

Then, at the end, as we approach the pre-ovulatory phase,energy tends to return. It's a period when you generally feel much more motivated, in a good mood, etc. All these mood fluctuations are linked to hormonal variations...

How long does this phase of the menstrual cycle last?

The menstrual cycle lasts about 28 days. Some women have shorter cycles, others longer. While the luteal phase always lasts 14 days, the follicular phase does not.

Long phase

In most cases, a longer follicular phase has no effect on your chances of getting pregnant. Theoretically, a longer cycle means that there are fewer ovulations in a year than in a normal or short cycle, and therefore fewer windows of opportunity for fertilization.

Warning: a very long follicular phase may be a sign of PCOS (polycystic ovary syndrome). Other external factors, such as stress, intense physical activity or jet lag, can also cause a long cycle.

Short phase

A follicular phase is said to be short when it lasts less than 10 days. Don't worry, there are no major health risks. However, if the duration is short, there is a risk of an immature egg that cannot be fertilized, or of chromosomal abnormalities

If your menstrual cycle is too short, it's quite possible to be taken care of by your healthcare professional. He or she can prescribe a suitable treatment (usually ovarian stimulation to encourage follicle growth).

In any case, if your cycles tend to be irregular and you're having trouble conceiving a child, consult a specialist!

How to calculate the arrival of the follicular phase?

To find out how long your follicular phase lasts, there's a method you can use: subtract 14 days from the date of your first day of periods. This will give you the duration of your luteal phase, which never changes.

Then simply subtract these 14 days from the total number of days. For a short cycle of 26 days, for example, it lasts 12 days. For a long cycle, of 34 days for example, it lasts 20 days.

Otherwise, an application to calculate your menstrual calendar will help you better define when each phase of your menstrual cycle takes place.

Our tips for staying in shape during the follicular phase!

The cycle is punctuated by hormonal changes that affect our morale. There are simple tips to help you get through this period. 

For your diet, avoid refined sugars, caffeine and alcohol, which are inflammatory foods that tend to aggravate pain of periods. During your periods, at the start of your follicular phase, it's best to focus on fruits and vegetables, rich in micronutrients to give you energy. To combat periods pain and inflammation, you can opt for chia, flax and pumpkin seeds, as well as oily fish, rich in omega 3.

At the end of your period, you can switch to :

  • Wholegrain cereals, legumes and root vegetables to give you energy;
  • Plant and animal proteins;
  • And always flax and pumpkin seeds.

Can you get pregnant during the follicular phase?

As detailed earlier in the article, this is a phase of endometrial evacuation, with no fertilization during the previous cycle, and preparation for a new ovulation and potential new fertilization. So it's not during this phase that the chances of getting pregnant are highest. 

But this doesn't mean it's impossible to get pregnant during this phase: there's no such thing as zero risk, so it's important to protect yourself during this phase if you don't want to get pregnant.

FAQs on the follicular phase

What are the differences between the follicular phase and the luteal phase?

The follicular phase is the first phase, including periods. During this phase, the body prepares for possible fertilization. The luteal phase is the period following ovulation, until the start of the next menstrual period.

What are the differences between the follicular phase and ovulation?

Ovulation marks the start of the luteal phase, the last phase of the cycle. Ovulation occurs thanks to everything that happens during the follicular phase.

What impact does the luteal phase have on fertility?

The luteal phase lasts 14 days. At the beginning of the luteal phase, ovulation takes place, and this is when the "window of fertility" occurs, i.e. the time when a woman is most fertile (around day 14).


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