Understanding the Menstrual Cycle and What it Means for your Health
There are enough comedic tropes out there about menstrual cycles that most people who menstruate have at least a vague idea of what to expect even before they begin menstruating, but so much of what we learn about our bodies through popular media is misleading or simply incorrect. Heavy bleeding, cramping, intense sweet cravings, are all popularised as being the norm and are even expected by some people. And whilst these things are certainly common, they are not the norm and may even indicate that something is out of balance. Considering those of us who menstruate will typically experience around 450 periods in our lifetime, knowing about this part of our health is definitely important. I’ve put together this blog post to give you a big overview of the menstrual cycle, the key hormonal players that impact it, and point to some of the more common issues that can affect normal menstruation.
What is the Menstrual Cycle and How Does it Work?
The menstrual cycle is much more than just bleeding once a month (if you have a regular cycle). It’s a complex process that dictates our fertility for the month and impacts our sleep, mood, strength and vitality, too. Sadly, so few women really understand or engage with their menstrual cycle and aren’t in tune with what’s happening in their bodies each month. This is a missed opportunity to better understand yourself and your own internal phases. Let’s take a closer look at the main phases of the menstrual cycle.
Before we jump into the menstrual cycle, here’s a quick overview of the major hormones that are involved:
Oestrogen: one of the primary sex hormones. Higher in the first half of the menstrual cycle
Progesterone: another key sex hormone. Higher in the second half of the menstrual cycle.
Follicle-stimulating hormone: this hormone stimulates the ovary to trigger follicle (egg) development and maturation, ready for ovulation
Luteinising hormone: triggers the release of the mature follicle from the ovary at ovulation
The Follicular Phase
Days 1-5: Bleeding Phase/ Menstruation
No matter the length of the previous cycle, your new menstrual cycle always begins on day 1 of your bleed. To be clear, this does not include any lead-up days where you might have a bit of spotting here or there, but the first day of actual bleeding. The length of time for your bleed may vary from 1-10 days, but about 3-5 days is typically considered optimal. During this time, your hormone levels are relatively low. Oestrogen levels start to slowly rise from around day 4. In comparing the menstrual cycle to the moon cycle, the bleeding phase would be the dark/ new moon.
What Can Go Wrong in the Bleeding Phase:
Heavier bleeding, or bleeding for a long time, might indicate certain health issues, such as:
Endometriosis
PCOS
Fibroids or polyp
Lack of ovulation (i.e. anovulatory cycle)
Low iron levels
Ovarian cysts
No bleeding or delayed bleeding might indicate:
No ovulation
PCOS
Hypothalamic amenorrhoea
Chronic or severe stress
Lack of adequate nutrition
What colour is your menstrual blood?
Red - bright red: normal, fresh blood
Very bright, fiery red: indicates too much '“heat” in the body, perhaps some inflammation
Dark brown: indicates old blood and perhaps a sluggish flow with lower uterine tone. Can indicate inflammation or endometriosis
Very watery, thin blood: tells us there is a need for blood-nourishing nutrients, or can indicate perimenopause or a hormonal imbalance
Lots of clots: some clotting is normal, however a high amount of clots indicates there is excessive flow and perhaps a need to improve uterine tone, or can indicate low iron levels or endometriosis
Days 6-13: Follicular Development/ the Proliferative Phase
From around day 4, oestrogen levels begin to rise, peaking at around day 12. It is during this period that the follicle in your ovary is growing and maturing, preparing to break free and travel the fallopian tubes. The endometrium (the lining in your uterus) starts growing tissue again in preparation for conception. This is the waxing moon phase of the menstrual cycle.
What Can Go Wrong in the Follicular Phase:
If follicular development doesn’t continue adequately, it can indicate poor ovarian function, and might indicate a conditions such as:
PCOS
Ovulation
On day 13-14, FSH rises and LH sharply rises in anticipation of ovulation on day 14 - the full moon phase of the menstrual cycle. It is around day 14, or the mid-point of your cycle, that you will have an increase in stamina, strength, and sometimes even better body image, thanks to that boost in hormone levels. Some people may feel a twinge or some mild cramping on one side of their lower abdomen around this time. This is known as ovulation pain and is the sensation of the mature egg being released from your ovary.
Signs you have ovulated include:
An increase in your body temperature - if you track your body temperature when you wake up each morning throughout the month, your temperature will increase slightly at the time of ovulation
Increased production of cervical mucous - a thicker, clear secretion from your vagina that can be sticky or feel like egg-white. This is cervical mucous, which is produced to lower the pH in the vagina to make a more hospitable environment for sperms, increasing the chances of conception.
What Can Go Wrong in the Ovulation Phase
Lack of ovulation usually indicates a hormonal issue. It may indicate:
Chronic or severe stress
Lack of adequate nutrition
PCOS
Hypothalamic amenorrhoea
Excessive oestrogen or insufficient LH
Ovarian cysts
Luteal Phase
Days 15-28: Luteal phase
After ovulation, we enter the luteal phase, which lasts the remaining two weeks of the menstrual cycle and can be seen as the waning moon phase of the menstrual cycle. Oestrogen, LH and FSH sharply decline on around 16-17 after ovulation. Meanwhile, progesterone rises, peaking around days 20-24 of the cycle. Oestrogen also has a second, smaller rise during the latter half of the luteal phase. In this phase of the cycle, both of these hormones are produced by the corpus luteum, which is the empy follicle from which the egg was released at ovulation. If conception and pregnancy occurs, the corpus luteum continues to produce progesterone in higher amounts during early embryo development. If no conception occurs, the corpus luteum “burns out” and progesterone and oestrogen decline again, until they reach the low levels seen as we return to the bleeding phase of a new cycle.
It is during the luteal phase of the cycle that many people can experience pre-menstrual symptoms, thanks to the rising and falling of progesterone and oestrogen. Here’s what your PMS symptoms might be telling you:
Intense Food Cravings
Your blood sugar levels might be out of whack. The hormonal changes during the luteal phase of your cycle can cause a drop in blood sugar levels, leaving you craving foods (particularly carbohydrates).
Mood Swings, Irritability, Muscle Tension
These can indicate high oestrogen and/or low progesterone levels during the luteal phase. An imbalance in these hormones can impact our HPA axis (the “fight or flight” response), increasing feelings of anxiety and tension.
Low Mood, Low Libido, Feeling Teary and Tired
These symptoms can indicate high oestrogen to progesterone ratio, which can impact neurotransmitter levels. If you are experiencing low mood before your period, it may be a sign of premenstrual dysphoric disorder. It’s important to reach out to a healthcare practitioner for investigations to rule this out.
Bloating
Bloating can indicate high levels of oestrogen, which can alter levels of hormones like aldosterone, which controls the body’s fluid balance, meaning there is a higher amount of water in the extracellular spaces in your body than normal. People who experience bloating pre-menstrually may find they experience increased urination at the onset of the period when their oestrogen levels decline again.
Cramping and Pain
These symptoms can indicate high levels of prostaglandins, which are involved in inflammation. It may also be due to an underlying condition such as endometriosis. Significant pain before or during your period needs further investigation to rule out other causes.
About the Author
Lizzie Stow is a degree-qualified naturopath from Newcastle, Australia.
To find out more about Lizzie, click here.
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References
Hechtman, L. (2019). The female reproductive system. In Clinical naturopathic medicine (2nd ed.). Elsevier.
Reed, B. G., & Carr, B. R. (2000). The normal menstrual cycle and the control of ovulation. In Endotext. MD Text.
Thiyagarajan, D. K., Basit, H., & Jeanmonod, R. (2022). Physiology, menstrual cycle. In StatPearls. StatPearls Publishing.
Trickey, R. (1998). Women, hormones and the menstrual cycle. Trickey Enterprises.