On Instagram, Dr Olivier Marpeau aka @mon.gyneco suggests putting in order what you think you know about the menstrual cycle. The key idea: a cycle is not necessarily based on 28 days, but it generally follows a hormonal logic in three stages, useful for better identifying what is usual… or what merits medical advice.
The three stages of the menstrual cycle
The first benchmark is simple: by convention, the cycle begins
the first day of menstruation and ends the day before the next period. It is this starting point which allows us to situate ourselves, whether the cycle is short, long or varies from one month to the next.
In his video, the gynecologist emphasizes the role of the pituitary gland, a gland located at the base of the brain, which secretes two hormones: LH and FSH. To simplify, it plays a central role, because FSH and LH act on the ovaries. But the functioning of the cycle is based more largely on a dialogue between the brain, the pituitary gland and the ovaries.
- Before ovulation, we talk about follicular phase. FSH stimulates the growth of follicles in the ovaries. One follicle becomes dominant, while the ovaries produce mostly estrogen. These hormones contribute in particular to the thickening of the endometrium, the mucous membrane which lines the inside of the uterus. To go further, you can understand how the menstrual cycle works step by step.
- When estrogen levels reach a certain level, an LH surge triggers ovulation : the ovary releases an oocyte. This is one of the points that the video usefully summarizes: the follicle that has ovulated then transforms into the corpus luteum. This produces progesterone, an important hormone for the following period. This mechanism is also linked to the role of the ovarian follicle in ovulation.
After ovulation comes luteal phase. Progesterone helps make the endometrium favorable for possible implantation. If there is no pregnancy, the corpus luteum regresses, progesterone and estrogen levels drop, then the superficial layer of the endometrium sheds: menstruation begins, and a new cycle begins.
Duration, symptoms: which may vary
The “classic” 28-day cycle, often presented with two 14-day periods, remains very theoretical. The important nuance is this: 28 days is an average benchmarknot a standard to achieve. Many people who menstruate have shorter or longer cycles, and some variations can occur throughout life.
On the other hand, we should not conclude that every irregularity is necessarily trivial. A prolonged absence of periods, very heavy bleeding or periods that become significantly unusual deserve to be discussed with a healthcare professional, without making a diagnosis yourself.
The signs experienced around periods also vary a lot. Some people have almost no symptoms, others notice physical or emotional changes. The most common may include:
- Pain in the lower abdomen before or during menstruation;
- Breast tension;
- Bloating;
- Nervousness or mood swings.
These symptoms are not systematic and their presence does not automatically mean that there is a problem. They can simply accompany the hormonal variations of the cycle. To better understand the role of the endometrium and hormones in the cycle, it is important to remember that estrogens and progesterone do not only act on the uterus: they also participate in sensations felt in the rest of the body.
However, certain signals should lead to requesting a
medical advice : very painful, heavy and recurring periods, very heavy or long periods which disrupt daily life, or a prolonged absence of periods. The goal is not to worry about the slightest change, but not to trivialize what becomes intense, lasting or unusual.