Follicular Phase (Follic-u-lar)

Let’s get down to the details… hormones!

This is where we begin to discover more about your unique cycle. Depending on your cycle length, you will either have a short, medium or long follicular phase. This phase is from the first day of flo (cycle day 1) through to ovulation.

A lot of hormonal work happens here.

Over this phase, women produce follicle stimulating hormone (FSH). This hormone stimulates the ovaries to produce around 5 to 20 follicles.

Follicles are tiny sacks (corpus luteum) that carry an ovum aka an egg. Over this phase, they will all grow with one or two becoming the dominant follicle at ~20mm.

Now we are going to get a little technical here… but I’ll explain in laymens terms thereafter.

A few days before ovulation, another hormone called the Luteinizing hormone (LH) is produced by gonadotropic cells in the anterior pituitary gland (your brain). The production of LH is regulated by Gonadotropin Releasing Hormone from the hypothalamus (another part of your brain). In females, an acute rise of LH triggers ovulation and development of the corpus luteum.

Let me break that down. From cycle day 1, a portion of our brain (the hypothalamus), secretes a hormone that stimulates follicle growth (FSH). Once those follicles are at a ripe stage (~20mm) your brain recognises that there is a dominant follicle and begins to surge Luteinizing hormone (LH) to trigger and rupture the dominant follicle out of the ovary and into the fallopian tube for conception.

WOW! Isn’t that amazing!

On top of these superwoman hormones, we also have estrogen and progestogen working in the background, levelling out to control the environment within the uterus in case conception takes place. I know right… and we were taught “it’s easy”.

Depending on your cycle length, you may have a short, long or anywhere in between follicular phase.

In the final days of this phase is where you are most fertile.

Check out our deep dive into hormones here.