We have lots of different hormones in our body, all with unique and important functions. On this page I am going to be speaking specifically about the subset of hormones that are classified as REPRODUCTIVE hormones.

Menstruating people move through a hormone rhythm every 25-35 days known as the menstrual cycle. The menstrual cycle consists of a follicular phase (the first part of which is your period/menses), ovulation, and a luteal phase.

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Here is a brief explanation of each


Takes place at the beginning of the follicular phase. Menses is the shedding of the innermost lining of your uterus (the endometrium), which occurs as a result of declining progesterone and estrogen levels in the late luteal phase. When menses have concluded, the endometrium is thin.

Follicular phase

A number of follicles in the ovary begin to grow and develop and ultimately one dominant follicle is selected each cycle. You can think of a follicle as a nest of cells surrounding an egg cell (oocyte). The cells of the growing follicle produce estrogen, which results in growth and thickening of the endometrium.


The dominant follicle ruptures, releasing an oocyte at the surface of the ovary so that it can travel along the fallopian tube and into the uterus (where it can be fertilized by sperm).

Luteal phase

The ruptured follicle transforms into a structure called the corpus luteum, which secretes progesterone and estrogen. Progesterone organizes the endometrium and causes basal body temperature to rise. In the absence of pregnancy, the corpus luteum regresses and thus progesterone and estrogen levels decline, triggering menses and the beginning of the next menstrual cycle.

Understanding Your Menstrual Cycle

You can see that there is an incredible symphony of events each menstrual cycle. Your period (menses) is just one part of the story.

Now you might be wondering, what is the control system behind each menstrual cycle?

Who is the symphony’s conductor?

The answer is the hypothalamic-pituitary-ovarian axis, or HPO axis for short. The HPO axis is a system of communication between your brain (which contains your hypothalamus and pituitary gland – the ‘HP’ of HPO axis) and your ovaries (the ‘O’ of HPO axis).

The hypothalamus secretes gonadotropin releasing hormone (GnRH), which causes the pituitary gland to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH). In the early follicular phase, FSH tells the ovary to start developing a cohort of follicles and in the late follicular phase, LH levels surge and result in rupture of the dominant follicle (ovulation). The estrogen and progesterone produced by the ovaries also communicate back to the brain – so it’s an intricate two-way communication system.

When thinking about healthy reproductive hormones, we want to see the production of both estrogen and progesterone each menstrual cycle. You may have noticed in the breakdown above that progesterone doesn’t come into the picture until ovulation has occurred. Therefore, the goal is to have ovulatory menstrual cycles. In an anovulatory menstrual cycle (a cycle in which ovulation does not occur), estrogen will be produced but there will be no or very little progesterone produced.

There are two times in the reproductive life of every menstruating person when they will not be ovulating regularly:

  • Postmenarche (aka. the first few years after getting your period)
  • Perimenopause (the menopause transition)

In postmenarche and perimenopause, the HPO axis has a few kinks in it which amount to some cycles being anovulatory, and this is expected. If you think of the HPO axis as being like a post office, in postmenarche the post office is brand new and the staff aren’t trained yet, so not all the messages are being delivered successfully. In perimenopause, the post office has been around for years and some of the staff have gone into retirement, so again, not all the messages are being delivered successfully.

On the other hand, there are a number of reasons why someone may not be ovulating regularly each month that are not an expected part of the reproductive lifespan. Here are some common examples (but please note this is not an exhaustive list):

  • PCOS (polycystic ovarian syndrome)
  • Birth control pill (blocks ovulation for contraceptive purposes)
  • Physical stresses such as under-eating and over-exercising
  • Psychological stresses
  • POI (primary ovarian insufficiency)
  • Thyroid conditions

See related: How a Naturopathic Doctor can help with Perimenopause

How can you tell if you’ve ovulated?

There are a number of ways to obtain clues about whether or not you ovulated each menstrual cycle:

  • Cervical mucus changes: Just prior to ovulation there will be increased production of cervical mucus and its consistency will change to that of a raw egg white (clear and slippery). This change occurs in order to facilitate sperm reaching the uterus. You’ll likely notice this as a change in your vaginal discharge when wiping after using the toilet.
  • Ovulation predictor kits: These kits test your urine for LH in order to detect the LH surge (which occurs ~36 hours prior to ovulation).
  • Tracking basal body temperature: Progesterone raises your core body temperature, therefore, ovulation is assumed if your basal body temperature increases by 0.3 degree C in the luteal phase for at least 10 days. This is an under-the-tongue measurement taken every morning before getting out of bed, using the bathroom, or having anything to eat or drink.
  • Serum progesterone: Progesterone levels can be measured in the blood in the mid-luteal phase to determine whether or not ovulation occurred. Two drawbacks to this method are: (1) it is impractical to do a blood test each month and (2) timing the mid-luteal phase is not always straightforward.
  • Menstrual cycle length: Generally speaking, menstrual cycles that are 25-35 days in length tend to be ovulatory.
  • PMS or PMS-like symptoms: PMS occurs when our brain perceives the event of ovulation and the resulting hormone production as stressful. In other words, it is an abnormal response of our nervous system to normal hormone changes. Therefore, PMS or non-bothersome PMS-like symptoms can be indicative of ovulation.

The take-home message

The menstrual cycle is an intricate series of events, only one part of which is your period. For optimal reproductive hormone health, the goal is ovulatory menstrual cycles. No ovulation… no progesterone. Both progesterone and estrogen are integral to overall health (bone health, brain health, sleep, mental health, cardiovascular health, fertility, uterine health, sexual health, and more!).

For those of you who learn better from a video, I recorded a webinar entitled “Understanding Your Menstrual Cycle” in which I cover all this and more. If you have any questions or are looking for support with your hormones, please book an initial consultation or free 15 minute meet & greet through the booking link below, and let’s get started!

Happy watching 🙂

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**Please remember that this article is meant for educational purposes only and should not be viewed as medical advice. You should always discuss any treatment option with a licensed healthcare provider to ensure it will be safe and effective for you.

Learn more about naturopathic care for perimenopause, menopause, and PMS & PMDD.