The phases of the menstrual cycle

   I have already mentioned before that the cycle is not only about menstruation, now let us see what the different phases of the cycle and their characteristics are.

1. Menstrual phase
   This is the part of the cycle that is the easiest to identify and the most obvious. The fist day of the cycle is the first day of menstrual bleeding. If conception did not happen in the previous cycle then the thickened endometrium sheds and leaves the uterus in form of bleeding through the vagina. This lasts for about 3-5 days with changing intensity during which we normally loose 25-80 ml of blood. We can talk about true menstruation only if it is preceded by ovulation. (I will have a separate post about the different types of bleeding.)

2. Follicular phase
   This part is about the ripening of the follicle and the egg inside. The brain produces FSH (Follicle Stimulating Hormone) which starts the ripening of multiple follicles in both the ovaries but after a few days one (or two) follicle becomes dominant, the others whither and get absorbed. The ripening follicle produces the main hormone of this phase, estrogen, that is responsible for the developing of the secondary female characteristics and the fertility. Estrogen induces multiple procedures in our body that would redound fertilization (more about this later). The length of this phase varies, it can differ from month to month. The reason for this is that the brain plays a central role in the process. Whatever can influence the working of the brain (stress, grief, travelling etc.) can also influence the production of the hormones and therefore the length of this phase.

3. Ovulation phase
   This is the most important part of the cycle in terms of fertility and health as well. Ovulation is when the ripe egg gets released from the ovary and starts its journey in the Fallopian tube towards the uterus. When the amount of estrogen, created by the ripening follicle, reaches a certain level it makes the brain produce LH (Luteinizing Hormone) that will cause the follicle (12-24 hours later) to break and release the egg. The level of this hormone is what ovulation predictor kits can show from urine. The egg lives for 12-24 hours after ovulation and can only be fertilized in the first 6-12 hours. In case there were two dominant follicles, the second egg gets released maximum 24 hours after the first one. The length of this phase is about 3 days, from the LH surge to the death of a possible second egg.

4. Luteal phase
   This part was named after the corpus luteum. When the egg gets released, the broken follicle remaining in the ovary turns into corpus luteum and starts producing the main hormone of this phase: progesterone. Progesterone blocks the production of FSH and estrogen thus preventing the ripening of new eggs. It also prepares the endometrium for a possible implantation. If fertilization has not occurred, the corpus luteum lives for 10-16 days, determining the length of the luteal phase for each woman individually. It is the same number of days in every month (+/- 1 day maximum). As the corpus luteum dies and the production of progesterone suddenly stops, the endometrium sheds and leaves the uterus through the vagina in the form of menstrual bleeding, a new cycle starts. So if you chart your cycles, as soon as ovulation happens you will be able to tell exactly which day your next period will come.

   So these are the phases of the menstrual cycle, I hope you found this article useful, you can ask questions or tell your opinion in the comment section below. In the next posts we will discuss the fertility signs, stay with me! 😉