Unlocking the Mystery of Menstruation

Have you ever wondered why you feel certain ways at different points throughout your monthly cycle? Having a more in-depth understanding of our menstrual cycle is empowering and important. Here's a brief look at just how much change your body goes through each month.

Understanding what the female body goes through during a menstrual cycle, how outside factors can affect a menstrual cycle, and how a menstrual cycle can affect day-to-day living should be common knowledge for adults. But it’s not. Before I walk you through what is happening throughout a monthly menstrual cycle, I would like to clarify that I did NOT know these details until I was probably 24 years old. Dead serious. I had no idea about the details of what was happening throughout my own menstrual cycle until more than 8 years after it started. And I bet it’s safe to assume that you might have waited a long time before figuring it out yourself.

No one ever taught this to me. The hour of sex-ed we got in junior high was far more comical than informational. The grown women around me didn’t talk about it (maybe they didn’t really know either). My friends/sisters and I had no problem being vocal about our periods, mood swings, cramping, bloating, bleeding, etc., but that didn’t mean we actually understood why it was all happening.

Periods have always been a taboo subject and, therefore, not an appropriate topic for public discussion (dumb). But now we live in the age of “share everything on social media” and even though 98% of me wishes that social media did not exist, I am glad to see some more people educating themselves on what is really going on throughout a monthly menstrual cycle… ya know, since it is a recurring part of nearly every female’s existence.

Understanding the details of your menstrual cycle is empowering. Learning about it not only gives you a picture of what is happening physically throughout your monthly cycle, it also can help you navigate “unexplained” emotions and the waves of motivation you might be feeling. The fact is, as women, our day-to-day experiences are influenced by a few critical variables that are specific only to our gender. These are things that can be more manageable if we have a more in-depth understanding of exactly what is happening.

What's happening during a monthly menstrual cycle?

There is no way to give an all-inclusive explanation of this phenomena without writing a small book, so I've chosen to highlight a few key hormones and processes. There may be a handful of words coming up whose definitions you are not familiar with. If you scroll to the bottom of this post, you can find a very rough "dictionary" to give you a better understanding of what these words mean and why they are important for you to know.

We describe a “normal” menstrual cycle by splitting it into phases, beginning with the Follicular Phase, progressing through Ovulation, and ending with the Luteal Phase. These phases are then broken down into early, mid, and late stages. Each stage is generally indicated by hormone changes.

You'll read that an average cycle length is 28 days, but I couldn’t find any research that showed more than 16% of the study participants having a consistent 28-day cycle… and 16% doesn’t sound like “average” to me so I hesitate to reinforce that number. Any cycle lasting 21-35 days would be considered “normal”.

The Follicular Phase

During the follicular phase we experience menses as the uterine lining sheds, rebuilding of the endometrium, rising estradiol and follicle-stimulating hormone levels, and the recruitment, selection, and maturation of ovarian follicles used to transport our one lucky egg into the uterus. All of this happens within 12-22 days (typically). Yes, in a 2-3 week time frame, our bodies go from shedding the endometrial lining because no egg was implanted to rebuilding it in preparation to try again.

Ovulation

If all goes well during the follicular phase, we see a cascade of hormonal events leading to ovulation when the egg is released from the mature ovarian follicle, down the Fallopian tube, and into the uterus. This is essentially spurred by a peak in estradiol, followed by a peak in luteinizing hormone and follicle-stimulating hormone, ending in the egg being released to find its Prince Charming (sperm) and get fertilized.

The Luteal Phase

During the luteal phase, the follicle that released the egg into the uterus during ovulation turns into the Corpus Luteum. With the Corpus Luteum around (powered by the luteinizing hormone) we see a peak in progesterone and high estrogen levels to prepare the body for pregnancy. All of that progesterone is a main reason you experience pregnancy-like symptoms (like your boobs getting bigger) in the days leading up to your period. Once your body realizes there has neither been any fertilization nor implantation of its one precious egg into the endometrial lining, the Corpus Luteum dips out and you get to start the cycle over.

Here's a another way to look into what happens during a menstrual cycle:

Vocabulary from Gately's Dictionary

Follicular Phase:

  • Lasts from the first day of menses until ovulation.

  • It is the longest and most variable-prone phase of the menstrual cycle.

  • Exhibits the most inter- and intra-woman variation in terms of length.

  • Characterized by lower basal body temperature.

  • Involves the recruitment and maturation of ovarian follicles (the most dominant will be chosen for ovulation - may the odds ever be in your favor).

Menses:

  • Refers to menstruation, commonly known as your “period” and involves the actual blood flow.

  • Fun fact: women typically lose around 30mL of blood each menstrual cycle.

Follicle Stimulating Hormone (FSH):

  • Used for prepping the egg launchers (ovarian follicles).

  • Plays a crucial role in every hormonal (steroid or protein) progression leading to ovulation (e.g., follicle recruitment, estradiol secretion, luteinizing hormone reception).

  • FSH is a protein, not a steroid.

Estrogen (Estradiol):

  • Estradiol is the primary form of estrogen observed throughout the menstrual cycle.

Endometrium:

  • The uterine lining where a fertilized egg implants to grow into a baby or sheds after no fertilized egg has been implanted.

Proliferation:

  • This phase involves the rebuilding of the endometrium after the uterus disposes of last month's endometrium during menses.

  • Proliferation typically occurs during the mid-late follicular phase.

Luteinising Hormone (LH):

  • Rises with estrogen levels as the follicular phase progresses toward ovulation.

  • Ovulation typically occurs within the next 12 hours after LH levels peak.

  • Influences the length of your cycle.

Ovulation:

  • Occurs when the ovarian follicle that matured during the follicular phase is released down the fallopian tube and into the uterus.

Luteal Phase:

  • Lasts from ovulation to menses.

  • Characterized by high basal body temperature.

  • The body prepares for pregnancy and progesterone peaks about mid-phase.

Corpus Luteum:

  • It is the egg-containing ovarian follicle turned progesterone-secreting mass of cells.

Progesterone:

  • Regulates the endometrium to prepare your body for pregnancy.

  • Peaks after ovulation when the corpus luteum is still active unless a fertilized egg is implanted into the endometrial lining.

  • The corpus luteum continues to supply progesterone for about 10 weeks of pregnancy before handing off responsibilities to the placenta.