The Period. It comes and goes each month, sometimes without much fuss, and other times it really makes it’s presence known. From it’s onset at puberty until the time one is trying to get pregnant, it can seem like a bit of a nuisance – but sometimes understanding something fully allows us to appreciate it a bit more. Sex education in elementary and high school gave us some of the basics, but perhaps not enough as it’s fairly common that women don’t fully understand their menstrual cycle. So, let’s change that!
There are different parts of the menstrual cycle, which are generally characterized by changing levels of hormones. Hormones act like messengers. When they arrive at their destination, they give information or instructions for another event to occur. The main goal of your menstrual cycle is to produce an egg that has the potential to be fertilized and grow within the uterus. Of course, the vast majority of the time fertilization does not occur, and therefore the cycle starts over again from the beginning. For the purposes of this blog, I’m going to use the “average” menstrual cycle, which is 28 days in duration, but this can vary from woman to woman. Let’s start at the beginning – what we call Day 1 – or the first day of your period/menstruation.
Day 1 – Menstruation Starts
Menstruation is the shedding of the lining of the uterus, and can last anywhere from 3-7 days. It is caused by a decrease in the amount of the sex hormones estrogen and progesterone that are being produced in the ovaries. Some women experience menstrual cramps, for which there are a few different contributing factors. I’ve written about these previously here.
Day 4-7 – Start of Follicular Phase
After menstruation is completed, our system starts to get ready to try again to produce an egg, and create an environment in which the egg can grow. The follicular phase is defined by a fairly steady increase in Follicle Stimulating Hormone (FSH) which signals to the ovaries to produce estrogen.
Day 7-14 – Follicular Phase
The increases estrogen levels in the ovary cause 10-20 follicles (groups of cells that contain an immature egg) to start to grow and mature. Ultimately only one makes it to the final maturation phase.
Day 14 – Ovulation
The rising levels of estrogen trigger another hormone called Leutinizing Hormone (LH) to rise. It is the sudden rise of LH that causes ovulation, or the release of the egg from the ovary, to occur.
Day 15-28 – Luteal Phase
The rest of the follicle from which the egg was released is now referred to as the corpus luteum, and these cells release some more estrogen, but mainly produce progesterone. These hormones combined stimulate the lining of the uterus to thicken in case fertilization were to occur. This would be the place where the embryo would nestle into and call home for the next 9 months! If fertilization does not occur, the corpus luteum will break down, and progesterone levels start to fall. The declining progesterone levels are the signal for menstruation to occur, which takes us back to Day 1.
Do you track your menstrual cycle?
This is one of the easiest ways to start to get a better idea of what is going on with your cycle. This is especially important if you are trying to conceive! It also gives us useful information if you suffer from PMS, menstrual cramps, PCOS, or irregular periods. Some of the solutions lie in correcting imbalances in hormones at different points in your cycle. It can be as easy as keeping track on paper, or using an app on your phone!
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