Periods: better understanding the 3 phases of the ovarian cycle

Why is talking about the ovarian cycle essential?

Menstruation is characterized by the shedding of the endometrium , the lining of the uterus, accompanied by bleeding. It occurs on average every month, except during pregnancy and after menopause. However, only 10 to 15% of women have a cycle that lasts exactly 28 days ; menstrual cycles last on average between 24 and 38 days. And in 20% of women, cycles are irregular! This is especially true during the first few years of menstruation, but also before menopause.

We often talk about periods and the " menstrual cycle ," but less so about the cycles that follow one another during these hormonal changes. Here's how to get a clearer understanding!

1. The follicular phase: preparation of the body

At the beginning of the menstrual cycle, the uterine lining thickens to prepare for a potential embryo. If fertilization does not occur, estrogen and progesterone levels drop , and the superficial layer of the endometrium sheds, resulting in menstruation . The follicular phase lasts between 13 and 14 days and is the phase that varies the most (it often shortens as menopause approaches). This phase 1 ends when luteinizing hormone levels rise sharply, triggering ovulation and the beginning of phase 2.

2. The ovulation phase: at the heart of fertility

The ovulatory phase begins when luteinizing hormone levels rise, triggering the release of the egg 16 to 32 hours later. The egg can be fertilized within 12 hours of release, and sperm can survive for up to 3 to 5 days, creating a fertile window of 6 days around ovulation. During ovulation, some women experience mild abdominal pain, sometimes called " mittelschmerz " (mid-abdomen pain), related to the release of the egg.

3. The luteal phase: awaiting fertilization

The luteal phase begins after ovulation and lasts approximately 14 days, unless fertilization occurs. During this period, the follicle becomes the corpus luteum , which produces progesterone to prepare the uterus for a possible pregnancy.
This hormone thickens the endometrium and cervical mucus, also slightly increasing body temperature. If the egg is not fertilized, the corpus luteum disappears, hormone levels drop, and menstruation begins .
In the event of pregnancy, the hCG hormone maintains the production of progesterone, which is detectable in pregnancy tests.

Did you know that these cycles influence your health?

Here are some tips for living in harmony with your menstrual cycle.

Menstrual cycle vs ovarian cycle: what's the difference?

The menstrual cycle and the ovarian cycle are two related but distinct processes in the regulation of female reproduction .

The menstrual cycle involves changes in the uterus, including the preparation of the endometrium for pregnancy and its shedding in the absence of fertilization (menstruation).

The ovarian cycle describes the cycle of the ovaries, including follicle maturation , ovulation, and corpus luteum formation . Both cycles are synchronized by hormones such as FSH, LH, estrogen, and progesterone .