Have you ever gone to the doctor for irregular menses or acne and been put on the birth control pill, and forgot all about your hormones until you’ve come off? Or perhaps you undergo monthly premenstrual (PMS) symptoms that range from moodiness, weight gain, acne, breast tenderness or pain? Or maybe you’re feeling fatigued or burnt out, and are wondering if its hormonally related but are unsure where to start? Hormones are a complex communication systems between different organs. Here we discuss the steps and hormones involved in a monthly menstrual cycle.

The classic menstrual cycle.

Hormones are little messengers that relay information between different parts of the body. The regulation of your monthly cycle depends on communication between the brain and the ovaries. The cycle is split into two parts, the “follicular phase” and the “luteal phase”, respectively.

The follicular phase begins on the first day of your menstrual cycle. (Cycle day 1). During the follicular phase – the brain hormone “FSH” (short for follicle stimulating hormone) rises and stimulates the ovaries to begin developing several follicles. Each follicle houses one egg, and its job is to provide essential nutrients for the development and maturation of the egg it houses.

As the eggs’ begin to mature, the follicles’ begin to release estrogen. Eventually, one follicle becomes the dominant follicle amongst the group, and the rest of the follicles disintegrate. This mature follicle continues to secrete estrogen at increasing levels. Estrogen is responsible for building the uterine lining in preparation for fertilization and implantation of the embryo, if that were to occur during that cycle. Eventually, the level of estrogen reaches a threshold which signals the brain to secrete a second hormone called “LH” (short for luteinizing hormone).

The LH hormone is released abruptly and causes the now mature follicle to release its egg from the ovary wall. This is known as “ovulation”. In a classic textbook menstrual cycle, this occurs around day 14. However this can fluctuate, it can occur earlier or later and this may be normal for you. From this point forward, you have entered the luteal phase.

Once the egg is released, it is swept into the fallopian tube, where it awaits fertilization. The follicle that once contained the developing egg, now becomes known as the “corpus luteum”.

The corpus luteum secretes the final hormone of the menstrual cycle, known as progesterone.

Progesterone is responsible for maintaining the thickness of the uterine lining. If fertilization were to occur, a thick uterine lining is required to allow for the embryo to implant into the uterine wall. If no fertilization occurs, eventually (in ~ 12-16 days) the levels of progesterone drops and results in menstruation. The cycle then resets.


Not all menstrual cycles are created equally.

It’s important to keep in mind that everyone is unique. Our genetics are different. Our environmental exposures are different. Our stressors are different. All these things impact how our hormones behave, and can subsequently change our monthly cycles. Variable cycle lengths, premenstrual symptoms (low back ache, moodiness, acne etc.) and painful, heavy periods are just a few of the things that can differ amongst cycles. Other gynaecological concerns may also be present, potentially complicating the picture.  Having a good understanding of a healthy hormone cycle is the first step to understanding where things may go array, what tests your doctors are sending you for and why, It also empowers you to ask questions and make informed decisions on how to gently bring the body back to balance.


– Dr. Ashley Damm, ND