Menstrual Cycle 101

I mean you know… but do you really know?

There is so much going on during the menstrual cycle. I want to break it down so that we have a better idea of how this process occurs. This also helps to lay the foundation for when we talk about kinks in the chain that can lead to menstrual irregularities.

There are three phases in the menstrual cycle: follicular phase, ovulatory phase, and luteal phase.

The mastermind behind these phases is the hypothalamic – pituitary – ovarian axis. This axis communicates back and forth between the brain and ovaries to tell your body what changes need to occur during your cycle.

Day 1 of your cycle is your first day of menstrual bleeding. Your progesterone and estrogen levels are low which causes the shedding of the endometrial lining.

During the follicular phase (first half of cycle), the hypothalamus releases Gonadotrophin Releasing Hormone (GnRH) which signals the release of Follicle Stimulating Hormone (FSH) from the pituitary gland. FSH stimulates the development of follicles within the ovaries. Each follicle contains a maturing egg. FSH levels eventually decline allowing for one dominant follicle and egg to develop. This dominant follicle produces estrogen, which signals Luteinizing Hormone (LH) levels to surge from the pituitary gland.

Cue the ovulatory phase. The LH surge signals the dominant follicle to rupture and the egg is released soon after.

The luteal phase follows next. LH and FSH levels decline and the ruptured follicle forms the corpus luteum, which produces progesterone. Progesterone and estrogen remain elevated during the luteal phase to help thicken and nurture the endometrium to prepare for possible implantation of a fertilized egg.

If fertilization does not occur, the corpus luteum degenerates and the decline in the progesterone and estrogen signals the endometrium to shed its lining, commencing the start of a new menstrual cycle!

The menstrual cycle is intricate, beautiful, and resilient. However, it can only take so much before imbalances start to develop.

If you feel like your menstrual cycle needs some TLC, let’s work together!