Menstrual Cycle 101

The menstrual cycle is a foundational aspect of women’s health, and yet it’s often misunderstood or even dismissed. As women, our bodies operate aligned to our menstrual cycle, so understanding what is happening during this time can help you recognize and understand the changes that occur in your body.

The American College of Obstetricians and Gynecologists (ACOG) has identified the menstrual cycle as the fifth vital sign. That means that it is really important in evaluating one's overall health!

Anyways, these are the things that we should have learned in high school sex education! Let’s dive right in:

The menstrual cycle is defined as the first day of your period (menstruation) to the day before your next period. In most women, this averages 28 days long, but can range between 21-35 days. The menstrual cycle is composed of 4 distinct time periods:

Menstruation

Menstruation is when you have your period. The first day of your period is considered day 1 of the menstrual cycle. This phase usually lasts 3-7 days for most.

During this time, estrogen and progesterone are at their lowest. Your period is stimulated by a drop in progesterone, which in turn increases prostaglandins. Prostaglandins are responsible for making the uterus contract and causing the uterine lining to shed, thus the bleed.

Having a period requires the body to use a lot of energy and resources, so naturally it is normal to feel more tired during this time. It is even normal to feel a little bit of cramping. However, debilitating fatigue and severely painful cramps that cause you to stay in bed all day or call out from work/school is not normal! This is a sign from the body that something is off, such as such as endometriosis, fibroids, adenomyosis, or hormone imbalances. If you do experience periods like this, I highly recommend working with a naturopathic doctor or functional medicine provider to figure out what is going on.

The Follicular Phase

The follicular phase is the first half of your menstrual cycle. This phase includes menstruation and goes until ovulation. The timeline of this phase (approximately days 1–13) can vary depending on individual cycle length.

During menstruation, estrogen & progesterone are low, triggering the pituitary gland to produce follicle-stimulating hormone (FSH). FSH is responsible for stimulating the ovaries to prepare a follicle for ovulation (a follicle is a small sac within the ovary that houses an immature egg). Estrogen then rises midway through the follicular phase, thickening the uterine lining (to create an ideal environment for potential embryo implantation) and supporting egg maturation (to ensure the egg is fully prepped for fertilization).

During the second half of the follicular phase, you might notice an increase in energy and mood, since estrogen promotes serotonin production, giving you a natural boost. However, those with hormone imbalances may experience symptoms like mood swings, anxiety, fatigue, headaches or migraines, changes in cervical mucus, sleep issues, and bloating or water retention during this time.

Ovulation

Ovulation usually occurs around day 14 of the menstrual cycle and lasts briefly for 24 hours. During this time, a surge in luteinizing hormone (LH) triggers the follicle to rupture, releasing a mature egg that is ready to be fertilized.

Hot tip: The 24 hours of ovulation is the ONLY time that you are fertile and able to become pregnant! However, it’s important to note that sperm can live within the female reproductive tract for up to 5-7 days, so the days leading up to ovulation are also considered part of your fertile window.  This is why tracking your cycle and understanding your body’s signs of approaching ovulation—such as changes in cervical mucus, increased libido, or mild cramping — can be helpful if you are trying to conceive (or not conceive!). Keeping an eye on these signs can help you identify your most fertile days for optimal timing.

Luteal Phase

The luteal phase is the time after ovulation until menstruation begins again. Typically this phase lasts from day 15-28.

At this time, the follicle that released the egg transforms into the corpus luteum. The corpus luteum produces both estrogen & progesterone in order to prepare the body to maintain a potential pregnancy. If fertilization did not occur, estrogen & progesterone will drop again, signaling to the body that it is time to shed the uterine lining, leading to menstruation. This drop in hormone levels triggers the start of the next menstrual cycle, marking the transition back to the follicular phase!

Common symptoms during this phase include bloating, breast tenderness, mood swings, and cravings. This is also when premenstrual symptoms (PMS) can appear, due to the interaction between progesterone, estrogen, and other hormonal shifts. Like I mentioned before, if you experience symptoms significant enough to impact your daily life, I highly recommend working with someone to evaluate what is going on!

I myself have experienced debilitatingly painful periods before and know what it’s like to dread your upcoming periods. I also know that it is confusing and daunting when trying to figure out how to balance your hormones. As a naturopathic doctor, I am here for you with the experience, advice, and tools to achieve balanced hormones and better periods! Remember, you don’t have to go through this alone — together, we can get you to having better periods.