MENSTRUAL CYCLE 101
Updated: Oct 28
Did you know that the menstrual cycle is more than just your period? There are two main phases and four main hormones that fluctuate throughout your cycle with the goal of releasing an egg for fertilization (aka pregnancy). If fertilization does not occur - you get your period and the cycle starts all over again.
Many of us received "sex ed" as young women, but the main focus was usually about tampon insertion or condom use. I don't know about you, but I learned shockingly little about the biology behind our periods. Lets dive deeper into the hormonal fluctuations and common symptoms that women experience which may indicate hormonal imbalance or underlying pathology.
Getting to know your cycle:
The average woman has her first period around age 12
Menopause (the cessation of menses for 12 consecutive months) occurs on average at age 51.
The average menstrual cycle lasts 26 to 34 days
Menstrual bleeding (your actual period) lasts roughly 3 to 6 days, typically being the heaviest on the 2nd day. *The first day of your menstrual flow is deemed day 1 of your cycle.
A woman experiences anywhere from 300 to 400 menstrual cycles in her lifetime
The first half of your cycle from onset of menstruation to ovulation is called the Follicular Phase and the second half from ovulation to onset of menstruation is called the Luteal Phase. Both of these phases involve hormones in your brain and your reproductive organs, all working together simultaneously to create the menstrual cycle.
1. The Follicular Phase
Typically days 1 to 14 of your cycle. The follicular phase begins with the onset of menstruation (the first day you bleed) and ends with ovulation.
A hormone called follicle stimulating hormone (FSH) is released from the pituitary gland within the brain which promotes follicular (egg) development within the ovary.
As the follicle develops, estrogen is released, causing the uterine lining (endometrium) to thicken in preparation for implantation of a fertilized egg.
The estrogen causes an increase in gonadotrophin-releasing hormone (GnRH) which produces another hormone - luteinizing hormone (LH).
Around day 12, LH levels spike up (or "surge") and the mature follicle is released from the ovary. Hello ovulation!
2. The Luteal Phase
Typically days 14 to 28 of the cycle, depending on the individual. This phase begins with the LH surge and ends when your next period starts.
When ovulation occurs, LH and FSH levels start to decline.
When the follicle releases the egg, the opened follicle forms a group of cells called the corpus luteum which makes progesterone.
If fertilization occurs, progesterone continues to be made which ensures that the uterine lining isn't shed. If fertilization doesn't occur (no egg meeting sperm this month), the corpus luteum disintegrates and progesterone levels decline. As they drop, the uterine lining sheds which is the beginning of the next menses.
And just like that your cycle starts all over again!
The entire cycle can be viewed below. (Image from uptodate.com)
If you are trying to conceive or just want more information about your menstrual cycle you can track your cycle easily using an app. In my fertility patients I ask that they tract their basal body temperature and cervical mucous for at least 2 cycles to give us more insight into their ovulatory status (more about this in an upcoming post - stay tuned)
Okay - so now you know about the hormones responsible for your cycle and what the average cycle looks like. Like many women, your cycle may not fit the textbook picture.
Common irregularities I see are:
Cycles longer than 34 days or shorter than 26 days
Mid-cycle spotting or spotting before your period
PMS Symptoms (bloating, breast tenderness, low back pain, mood changes, changes in bowel movements,. etc.)
If you experience any of the above symptoms it may be useful to get to know your cycle more intimately in order to get to the root cause of your concerns.
Getting to know your menstrual cycle and what is normal for you can give you useful insight into your health and wellbeing, especially when it comes to hormonal health.
I see many women in my practice who are told their symptoms are "normal" and not to worry about them. In my opinion, you should never have to suffer through them or take oral contraceptive pills to cover them up.
Why do Menstrual irregularities occur?
There are many reasons that can contribute to irregular menses, some of which include:
Hormonal imbalance(s) such as excess estrogen, inadequate progesterone, or thyroid dysfunction
Genetic variation and/or underlying health concerns (such as endometriosis, polycystic ovarian syndrome, uterine fibroids, and more).
As a naturopathic doctor I always aim to determine the underlying cause of health concerns and address the root cause instead of covering up the symptoms. This means a full intake, comprehensive testing, and adequate workup. It also means never using oral contraceptive pills to "regulate" hormones (they mask issues, they do not regulate hormones).
It is important to see a qualified healthcare practitioner in order to rule out underlying pathology such as PCOS, endometriosis or uterine fibroids.
I encourage you to get to know your cycle by tracking the changes and symptoms you experience every month and find a practitioner who wants to dig a little deeper for you. Here's to creating happy hormones!
As always, feel free to reach out if you have any questions or comments, and thanks for stopping by!
Health-related information contained in this post is intended to be general in nature and should not be used as a substitute for a visit with a Naturopathic Doctor or other healthcare provider. The advice is intended to offer only a general basis for individuals to discuss their medical condition with their healthcare provider. Always consult your licensed Naturopathic Doctor before making changes to your treatment protocol.
Romm, A. (2018). Botanical medicine for women's health (2nd ed.). St. Louis, Missouri: Elsevier.
Welt, C (2019). Evaluation of menstrual cycle and timing of ovulation. Retrieved Oct 5, 2020, from https://www.uptodate.com/contents/evaluation-of-the-menstrual-cycle-and-timing-of-ovulation
Welt, C. (2019). Physiology of the normal menstrual cycle. Retrieved Sept 30, 2020, from https://www.uptodate.com/contents/physiology-of-the-normal-menstrual-cycle