*Note: hormonal forms of birth control (contraception) such as pills, certain IUDs, implants, injections, vaginal rings, and skin patches can change your cycles: timing, length, and flow.  

A woman’s period, especially a natural menstrual cycle*, can give a lot of information about her overall health. Some ancient cultures believed that female hormones mimic the waxing and waning of the moon, hence the nickname, “moon (lunar) time”.  About half of women ovulate and bleed in sync with the full and new moon or vice-versa, due to the similar length of the lunar and menstrual cycles. We know the moon affects ocean tides, so why couldn’t it affect our bodies (mood, sexual desires, and reproductive tendencies) when the average human adult female is comprised of ~55% water? Whether the connection is scientifically proven, it may add personal meaning for some to observe their period in relation to the lunar calendar.  


The Basics

The average cycle length is 28 days long. That is, there are 28 days between the first day of bleeding (Cycle Day 1) and the next (Cycle Day 1) with consecutive periods (menses). Somewhat startlingly, anything between 21 and 45 days is considered “normal”, but 24 to 38 days is more common.  The important thing is that the time between periods is consistent, give or take a few days. 

Period length is the time from Cycle Day 1 and the last day of bleeding, which can range from as little as 2 days to about a week. Spotting on either end doesn’t count. Again, this number shouldn’t change dramatically each cycle. 

Within a year or two of when menstruation begins (menarche), cycles tend to be longer and more irregular as well as toward the end of woman’s reproductive years (peri-menopause). Menopause is defined as the absence of a period for 12 consecutive months with no other organic cause. 

If the egg (ova) released by your ovary each month (or so) isn’t fertilized, your uterus sheds its lining through the vagina. The quality of your menstrual flow, i.e. the amount of blood (light, moderate or heavy) can also vary greatly within a cycle but shouldn’t change as much from cycle to cycle. 

I always encourage my patients (and friends and family) to track their cycles to increase awareness of: 1) normal patterns and possible pathological changes; 2) the link between hormonal processes and the way we think, feel, and act; and 3) a potential connection with nature for fun—is there any predictability with the moon when it comes to your cycle? Many free modern apps are available (e.g., Flo, Clue, Eve, etc.) and double as family planning tools.  There is even cycle tracking trough Apple’s Health App now. I’ve been tracking since 2010 and have logged 132 periods to date using MyMonthlyCycles—an old-school web-based tool my friends and I discovered toward the end of university when I finally began to appreciate my “monthly visitor”.  


Changes in your body’s level of sex hormones (estrogen and progesterone), which are released primarily by the ovaries, are responsible for the ebb and flow of a menstrual period as well as PMS symptoms and their severity. 


PMS (pre-menstrual syndrome)

A cluster of symptoms that typically occur in the second half of cycle, from the time of ovulation (e.g., Cycle Day 14) to Cycle Day 1 (of the proceeding period), such as: 

  • Acne
  • Lower abdominal and back pain / cramping
  • Water-retention / bloating
  • Breast tenderness
  • Increased hunger and cravings
  • Digestive issues (constipation / diarrhea) 
  • Sleep issues
  • Headaches
  • Mood changes (mood swings, irritability, anxiety, etc.)

In the last half of our cycle, our bodies have to work harder to breakdown (metabolize) extra hormones in our bloodstream. Here, the liver is the primary organ of detoxification, so any form of liver support should improve one’s period symptoms.  Stay-tuned for Part 2 of 3: What can I do about a less than ideal period experience?

If you (or someone you know) would benefit from building a better relationship with your (their) period, I am always available (and eager) for consultation on one of my favourite topics.  

Wishing you month-long hormonal harmony. 

In health,
Dr. Vanessa