The Menstrual cycle is a complex hormonal orchestra that occurs every 25-35 days. Understanding the inner workings of your cycles, phases and hormones can help you have a better understanding of your body and when something might be off. In medical school they teach doctors what "normal" looks like, so that we can pick up on when something isn't right. So here is my crash course on the menstrual cycle and the hormones, phases and sign/symptoms involved.
Your menstrual cycle starts on Day 1. This is the first day of bleeding. Proper bleeding, not just spotting. You know what I mean ;) This is the Follicular Phase. During this phase, here is the run down on what goes on.
The follicular phase
This is the first half or approx first 14 days of the menstrual cycle. During this time, estrogen slowly rises along with FSH (follicle stimulating hormone) and eventually LH (Luteinizing hormone). These hormones control the growth of the endometrial lining (build up of blood in the uterus) and prepare the follicles (egg) to be released around ovulation.
There are a lot of hormones at play here. This cascade typically takes a full 2 weeks to complete, however, in irregular cycles, it often takes longer. Stress and outside factors can greatly impact the follicular phase and delay ovulation or even cause anovulation (lack of ovulation).
Let’s go through the hormones of the follicular phase ✨
▫️FSH: Follicle stimulating hormone: Produced in the anterior pituitary gland in the brain and absorbed by the follicular receptors on the follicular wall (the protective casing around the actual egg/oocyte). This is the main hormone responsible for maturing the egg-follicle complex.
▫️Estrogen: Follicles then produce estradiol (the most potent form of estrogen). Estradiol helps mature the eggs further, grow the endometrial lining on the inside of the uterus and transform cervical fluid into a fertile substrate. Estrogen is lowest during menstruation and highest right before ovulation.
▫️LH: Luteinizing hormone: Produced in the anterior pituitary gland in the brain and helps to continue the growth of follicles and assists with the actual event of ovulation. It then helps after ovulation to transform the follicle into the corpus luteum which then produces progesterone.
THEN comes Ovulation (In a person that is having ovulatory cycles). Ovulation typically occurs between days 12-16 of the cycle.
3 telltale signs that you’ve ovulated. It’s about to get personal, but I LOVE talking about how the human body works!! So let’s get talking about stuff that’s typically TMI. I want to normalize the language and discussions around the inner workings of the human body, after all, we all have one!
💦 Number one: Cervical fluid. Female bodies secrete fluid throughout their cycle. After your period stops, you’ll typically notice a lack of cervical fluid. Then comes sticky fluid. When ovulation is nearing, CF is usually wet/watery or creamy like lotion. Finally, right before you ovulate, your cervical fluid will resemble raw egg whites. This is a good indicator that you may have ovulated!
🤞🏼Number two: Cervical position. This one requires insertion of your fingers into the vagina to check on the height and openness of the cervix and cervical os (opening). When you are ovulating, your cervix will be high and open.
🌡 Number three: Basal Body Temperature. This one requires you to take your oral temperature first thing upon waking in the morning. Before you get up, drink water or move your body. Take your temp and record (my fave app for this is Kindara). After you've ovulated, your body temperature will increase the next day and you can see it on the chart! This is because the hormone Progesterone is thermogenic (heat producing) and actually increases your body temp! How cool! After ovulating you will see the temp maintain is elevation and then slowly dip before your period if no pregnancy occurs.
The Luteal Phase
The Luteal phase of the menstrual cycle is the second half or approx second 14 days of the cycle. During this time, progesterone rises and does a few very important things.
▫️Raises the basal body temperature, changes cervical fluid and cervical positioning
▫️Stops the ovaries from releasing any other eggs during the remainder of the cycle and/or pregnancy
▫️Causes the uterine lining to thicken and hold firmly, until, if no pregnancy occurs, and progesterone drops, then bleeding commences.
▫️Progesterone is heat producing and is mostly made by the corpus luteum. The corpus luteum produces the progesterone needed to support a pregnancy until the end of the first trimester when the Placenta takes over.
If no pregnancy occurs, then bleeding commences with the drop in progesterone signaling to the body to release the endometrial lining. Voila! Period.