The Phases of the Menstrual Cycle 

 December 9, 2021

By  Kayla DiGaetano

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Women have been menstruating since the beginning of time. In fact, it is a normal and healthy part of life for women to experience their menstrual cycle every month until menopause occurs.

This is what Sex Ed class should have really taught us – the three phases of our menstrual cycle.

Follicular Phase

This phase occurs from approximately day 1-14. Day 1 as we have mentioned before is the day you bleed (womp womp womp…don’t forget to pack some tampons!)

The end of the bleeding phase is marked by ovulation. While we’re bleeding, the ovaries are prepping themselves to ovulate again (getting ready for showtime!)

There’s a gland at the base of our brain called the pituitary gland that releases a hormone called FSH – follicle-stimulating hormone. This hormone causes several follicles to rise on the surface of the ovary. Think of these follicles as little army girls all bunched together rising to a challenge. These follicles each have their own egg.


Eventually, one of these follicles becomes dominant (aka the chosen one) and within it, develops a single mature egg.

This reminds me of the hunger games when Katniss Everdeen volunteers as tribute. – “No! I volunteer! I volunteer as tribute!”

This mature egg produces the hormone estrogen. Estrogen increases over the follicular phase and peaks the day or two prior to ovulation.

In response to the increased estrogen, the lining of the uterus (endometrium) becomes thicker and more enriched with blood in the second part of this phase (when you’re done bleeding).

Around days 9-12 you may notice a slight increase in sex drive. This is when a brief surge of testosterone occurs. Pretty interesting how our bodies elevate your libido and increase your testosterone before you ovulate (aka prime baby-making time).

Around Days 12 through 14, is the release of LH – Luteinizing hormone is released and marks the beginning of the ovulatory phase.

Ovulatory Phase

This is the phase between the follicular and luteal phases. This is the release of the mature egg that happens on about day 14. This is in result to the surge in LH (Luteinizing hormone) and FSH (follicular stimulating hormone) over the previous day(s). After the release, the egg enters the fallopian tube where fertilization may take place if sperm is present. If the egg is not fertilized, it will disintegrate after one day. Despite the fact your egg only lives about 24 hours, sperm live up to 3-5 days and you’re still considered fertile for 5-6 days of each month!


Luteal Phase

The luteal phase is days 14-28 where FSH and LH decrease. The corpus luteum (tissue that forms in the ovary) produces progesterone. If the egg is fertilized, the corpus luteum continues to produce progesterone which prevents the uterine lining from shedding. If fertilization has not occurred (aka no baby on the way), the corpus luteum disintegrates, which causes progesterone levels to drop and signals the uterine lining to shed aka the entire cycle starts all over again!

Our bodies are so unique in how we have this awesome flow of hormones rising and falling throughout our cycle. Now that we have a better understanding of what happens at a biological level, let’s unravel the truth about what a period should really be like.

Let’s take you there in my next blog – “Is my Period normal?”.

Kayla DiGaetano

Educating clients on the importance of Metabolic Health, and instilling in them the drive and commitment needed throughout my athletic career, helps my clients achieve and surpass their fitness goals.

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