A typical menstrual cycle: what happens to me and what hormones are involved?
In the process of learning more about your body , it can be empowering and useful to understand your menstrual cycle. You might have often wondered why sometimes your emotions take you on a rollercoaster ride, and how this is part of your larger cycle overall. This article aims to teach you just this: understand what your menstrual cycle is composed of, and what you can expect in all the different phases.
The menstrual cycle refers to the changes in the reproductive organs that serve to make reproduction possible. The length of one’s menstrual cycle will be on average somewhere between 20 days and 35 days. Although the length may vary, a typical menstrual cycle will be composed of 4 phases. Their order, and the different processes involved, is similar amongst menstruators.
This infographic provides us with an overview of what happens during your menstrual cycle. Do not stress, we will slowly go through it to make sure that you are a menstrual cycle expert at the end of this! For the ease of explaining, we will assume that the menstruator’s cycle is 28 days.
Your menstrual cycle is mostly controlled by hormones that are released by a small part of the brain called the hypothalamus, as well as by hormones produced by your reproductive organs. This causes changes in the endometrium as well, which is the lining of the inside of the uterus.
We will now go on to explain the 4 different parts of your menstrual cycle!
1. Menstruation - day 1-5
Your cycle starts on the first day of bleeding (menstruation). In this phase, the endometrial lining sheds, which is due to the ovarian hormone progesterone being very low. Your period will last somewhere between 3 and 7 days.
2. Follicular phase (pre-egg release) - day 6-13
After your endometrial lining has shed and your period is over, the follicular phase starts. This phase prepares one of your egg cells for fertilization.
The hormones FSH (follicle stimulating hormone) and LH (luteinizing hormone) are released by a small part of your brain called the hypothalamus. These hormones cause follicles in your ovaries to develop. Follicles contain immature egg cells, and can be seen as the packaging of your egg cells.
The dominant follicle, i.e. the one that is growing the most, will start releasing estrogen (one of your ovarian hormones). This estrogen will lead to the endometrium growing and thickening, as well as making the cervix (the part between your vagina and uterus) more welcoming for sperm. This is all in preparation for potential fertilization!
3. Ovulation (egg release) - around day 14
As the climax of all the work your body has been doing, ovulation occurs.
As the estrogen levels are increasing as it is produced by the follicle, a lot of FSH and LH is released. This causes the dominant follicle to rupture, releasing the egg cell down your fallopian tubes (these connect your ovaries to your uterus).
No matter your cycle length, ovulation always occurs 14 days before the first day of your menstruation.
4. Luteal phase (post-egg release)
The follicle, aka the packaging of your egg cell, will now be left behind. In fancy terms, this is called the corpus luteum.
This corpus luteum will keep on releasing estrogen and progesterone, causing the endometrial lining to thicken even more. Also, they make sure that no more FSH and LH are released, so no other follicles can develop. Now the body will wait to see if fertilization occurs, i.e. sperm enters the body.
If fertilization occurs, and you are pregnant, the embryo (the combined egg and sperm cell) will release hormones that keep the corpus luteum alive.
If no fertilization occurs, the corpus luteum will degenerate. Estrogen and progesterone will start to drop, causing the endometrial layer to be shed. This is the start of your period and brings us back to the beginning of the cycle!
There you have it, a biological overview of what happens in your body during a typical menstrual cycle. What parts do you recognize from your textbooks and which were new? Let us know!