Menstrual cycle: everything you need to know about the female cycle

Whether it's to find out when your next period will fall, to conceive a baby, or simply to understand yourself better, knowing how the menstrual cycle works is very interesting. So we'll tell you everything you need to know in this article.

What is the menstrual cycle?

From puberty, to the onset of menstruation, to the menopause, women have a menstrual cycle lasting around 35 years. A woman's fertility takes the form of a cycle, divided into 4 phases. During these 4 phases, there are hormonal fluctuations, which affect many aspects of a woman's life.

The menstrual cycle lasts around 28 days, but the length varies from person to person: some have a very short cycle of 21 days, while others have much longer cycles of 30 days or more.

What are the hormones involved in the menstrual cycle?

As explained above, hormones and their fluctuations govern the different phases of the menstrual cycle.

Estrogen and progesterone: the best-known hormones

Estrogen and progesterone are the main and most important hormones in the menstrual cycle. Estrogens have a regulatory role. They are hormones produced by the follicles (located in the ovaries) and make the endometrium (the lining of the uterus) thicker, ready to receive a fertilized egg. Just before ovulation, estrogen levels rise.

Progesterone is the second sex hormone. It is produced when the ovum has already been released, by the so-called "corpus luteum" (the remains of the follicle). This hormone is very useful in preserving the endometrium and allowing the implantation of a fertilized egg. Progesterone peaks on the 21st day of the menstrual cycle, one week after ovulation.

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Follicle-stimulating hormone (FSH) is not secreted by the ovum, but by the pituitary gland in the brain. What does it do? To bring the follicles in the ovary to maturity. This hormone also plays a role at the onset of puberty.

Levels rise during menstruation, falling again just before ovulation.

Luteinizing hormone (LH) is also a hormone produced in the brain. Its mission? That ovulation occurs, releasing the egg ready for fertilization.

What are the phases of the menstrual cycle?

The menstrual cycle is made up of different phases, each with its own particularity:

1. Follicular phase

The first phase begins on the first day of menstruation, which corresponds to the first day of the cycle and the follicular phase. It generally ends on day 14, with ovulation or the ovulatory period. The ovaries are in fact preparing to release an egg. FSH is secreted by the pituitary gland, causing the follicles to grow, which in turn produce estrogen.

At the end of follicle growth, with the peak of luteinizing hormone, an oocyte is released. Together with the sperm, the oocyte forms the first cells of the embryo during fertilization.

The endometrium thickens in preparation for the fertilized egg. During this phase, you may experience

  • migraines
  • increased libido
  • swollen breasts

2. Ovulation

The third phase isovulation. This generally occurs on the 14th day of the cycle. Once released, the ovum takes 24 hours to reach the fallopian tubes, and survives between 24 and 48 hours. For pregnancy to occur, the egg must be fertilized within this timeframe.

Several signs may appear during this phase:

  • an increase in your body temperature: to make the ground more favorable for sperm and their survival, the temperature generally rises by 0.5 degrees.
  • During this period, the cervix is also more open, making discharge whiter.

3. Luteal phase

Finally, once the egg has been released, the luteal phase begins. During the luteal phase, progesterone levels rise to help the uterus mature. Then, at around 21 days, progesterone production begins to decline. When estrogen and progesterone levels reach a very low level, bleeding begins, which leads to menstrual bleeding.

During the luteal phase, you may experience various symptoms:

  • The first is the onset of PMS. PMS stands for premenstrual syndrome. An estimated 80% of women suffer from PMS. PMS can manifest itself in many different ways: headaches, intestinal problems, joint pain, mood swings and so on.
  • You may also experience hormonal acne.

4. Arrival of menstruation

The first day of menstruation, and therefore of the cycle, also marks the start of the follicular phase. If your period arrives, this means that the egg has not been fertilized this month. The lining of the uterus, called the endometrium, will then disintegrate, and this is where bloody discharge will appear. The menstrual flow is also made up of uterine mucosa. Menstruation, its frequency and pain vary from woman to woman. Some have heavy flows , others light. Bleeding lasts from 3 to 7 days most of the time.

During your period, you may experience a variety of symptoms, such as menstrual cramps, abdominal pain, migraines, etc.

How can I calculate the length of my menstrual cycle?

Knowing your menstrual cycle and knowing when your period is due or when you're most likely to get pregnant is very practical.

What day does your period arrive?

The average cycle lasts 28 days. The arrival of your period marks the beginning of a new cycle and the end of the previous one.

To better predict the arrival of your period, you can note and count the days in a menstrual cycle calendaror use a menstrual cycle tracking application.

What to do about irregular cycles?

Irregular cycles can be a heavy mental burden for those who suffer from them.

It's normal for your cycles to be irregular when you first start menstruating: the body needs to adapt to the hormonal changes. After 1 year, your cycle is generally regular.

Of course, there are periods in your life when your periods can become more irregular: we're thinking in particular of pregnancy and breastfeeding, but also of periods of stress.

So there are many factors in our lives that can influence the regularity of your period. If your cycles are generally irregular, consult your doctor: it could be a more serious problem, such as PCOS.

When is the best time to get pregnant?

Your best chance of getting pregnant is at the moment of ovulation. Ovulation generally occurs on the 14th day of the cycle. In fact, while the length of the follicular phase (before ovulation) varies, the luteal phase always lasts 14 days.

This means that your most fertile time is between the 4th day before ovulation and the day after ovulation. In fact, since sperm cells have a life expectancy of 5 days, you can get pregnant from sexual intercourse in the days leading up to ovulation.

How do you know if you want to? As ovulation generally occurs around the 14th day of the cycle, you can start by counting on a calendar, or using a cycle-tracking app. Then, ovulation leads to various symptoms (more or less noticeable depending on the individual). For example, you may feel

  • a feeling of heaviness and pain in the lower abdomen (on the side where the egg is released)
  • bloating
  • a change in cervical mucus: secretions tend to become egg-white-like, more slippery and translucent
  • increased libido
  • a rise in your body temperature
  • some women also experience spotting (light blood loss) during ovulation.

What impact does the menstrual cycle have on daily life?

As explained above, the menstrual cycle is divided into several main periods, all driven by hormonal changes. And hormonal fluctuations have a global impact on your body, mind and so on.

For example, during the first phase of the menstrual cycle, it's common to experience symptoms such as fatigue and sleep disturbance.

During the follicular phase (after menstruation and before ovulation), your libido may increase.

And during the luteal phase, the famous PMS (pre-menstrual syndrome) occurs. 80% of women are affected by PMS, to varying degrees of intensity.

PMS manifests itself in different ways for different women, but here are the most common symptoms:

  • mood swings
  • irritability
  • fatigue
  • heightened sensitivity
  • sleep disorders
  • anxiety
  • stress
  • sadness

In some severe forms of PMS, known as premenstrual dysphoric disorder (PMDD), symptoms are so severe that they lead to suicidal thoughts, depressed mood, etc. This disorder affects 3% to 8% of women.

Menstrual cycle FAQ

How do I know if my menstrual cycle is 28 or 21 days long?

The length of the cycle varies. If your period arrives after 21 days, then the length of your cycle is 21 days. If your period arrives after 28 days, your cycle lasts 28 days.

How can I calculate my menstrual cycle?

There are a number of ways you can figure out your menstrual cycle: simply note the days of your period in your calendar. Alternatively, there are mobile applications that allow you to track your cycle according to the date of your period, your feelings, your presumed ovulation date, etc. Handy for planning your vacations or anything else!

Can I get pregnant just after my period?

It's unlikely that you'll get pregnant right after your period. But it's not impossible: if your cycle is very short and ovulation takes place just after your period, if you have unprotected sex, you run the risk of getting pregnant.

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