Menstrual Cycle Explained

Last updated: May 30th, 2019 at 12:13 pm

Author, Linda Ryan, BA, Lic. TCM, CH

Menstrual Cycle Explained

How Long is a menstrual cycle?

You may have heard that the average periodMenstrual cycle cycle that a woman has is a 28 day menstrual cycle and that ovulation happens on day 14.  That is a “textbook” menstrual cycle, but not every woman has a textbook perfect cycle. Some women have longer or shorter cycles, which varies the day of ovulation, the length of time before ovulation (the follicular phase) and the length of time after ovulation (the luteal phase). The good news is that things do not have to be a textbook 28 days perfect to be fertile and get pregnant.  Also, a woman’s period cycle days can change from month to month. Women with conditions like PCOS can have much longer cycles than 28 days.

The period cycle days are broken into 2 Phases with Ovulation happening between them: The days from the first day of your bleed up to ovulation is called the Follicular Phase (the follicles grow during this time period).  The time period after ovulation is called the Luteal Phase.  The length of days within each cycle varies from woman to woman so even though numbered days are listed below, the amount of days in your personal period cycle may be different.  As long as you are aware of this you can follow along what should be happening in an “average period cycle”.

The Menstrual Period Cycle Days are:

Menstrual cycle Day 1 (Follicular Phase)

Day 1 of your menstrual cycle is the first day of full flow blood flow (spotting is not considered day 1). The amount of days women bleed varies significantly.  It can be anywhere from 1 to 10 days (or more). Textbook menstrual cycle bleeding is about 3-4 days. Some women also experience spotting of blood before their full menstrual flow begins. Day 1 is usually considered when the full flow starts.  If the full flow starts in the night, it is the following morning that is considered to be day 1 of your menstrual cycle.

Menstrual cycle Days 2-14  (Follicular Phase)

This is the follicular phase. Shedding of the womb lining can last any number of days during this time, the norm is considered to be 3-4 days of full flow.  Preparation for a new cycle also begins during the follicular phase.  Follicles on the ovaries become active (due to Follicle Stimulating Hormone), the endometrium (lining of the womb) starts to grow and thicken again (due to the hormone estrogen) and the fertile cervical mucous begins to thin.  One follicle becomes dominant, it grows higher than the others.  The egg matures inside this dominant follicle.  Day 3 Blood tests can help you determine if your hormones levels are normal.

Menstrual cycle Day 14 Ovulation time- Most fertile days of cycle

This is considered to be midcycle (of a 28 day menstrual cycle) and is usually when ovulation takes place: these are the fertile days of a woman. Rising estrogen levels trigger the release of LH (Luteinising Hormone, also referred to as an LH surge). This rising level of LH causes ovulation (which is the releasing an egg from a follicle). The timing of ovulation is not always on day 14 for all women; it can occur anywhere is the menstrual cycle, the timing of ovulation depends on the individual woman.  Looking for and tracking fertile cervical mucous can help you determine the most fertile days of cycle.

Related Article: Mid Cycle Spotting: Causes and what you can do about it

Menstrual cycle Days 15-22 (Luteal Phase)

This is after ovulation and the part of the menstrual cycle is referred to as the luteal phase. The follicle collapses down after the egg is released (ovulation). This collapsed follicle is now called the corpus luteum, and it pumps out progesterone.  Progesterone creates a favourable environment for the implantation of an embryo into the endometrium (womb lining). Your Progesterone level should be at it’s peak 7 days after ovulation (day 21 of a textbook 28 day cycle).  Day 21 blood tests are used to determine if a woman has ovulated.  These Progesterone tests are also used to determine of the progesterone level is high enough to support a developing embryo and maintain a pregnancy.

Menstrual cycle Days 23 to 24 (Luteal Phase)

If implantation of an embryo does not occur, then the estrogen and progesterone levels start to fall during these days of the menstrual cycle.

Menstrual cycle Days 25 to 28 (in Luteal Phase)

Progesterone levels continue to fall. The falling progesterone levels eventually trigger the shedding of the endometrium (lining of the womb) after day 28 and then the period cycle days start over again..

Why is it good to understand your Menstrual Cycle?

Knowing when your fertile window of opportunity is essential to getting pregnant.  As each woman’s menstrual cycle can vary in the length, thus making for a varied time of ovulation, you may want to try BBT charting , Tracking Your Fertile Cervical Mucous or ovulation predictor sticks to help you pin point your fertile window, the best time to try to conceive.  Clearblue make a good quality Ovulation predictor stick, you can click here to read more about the menstrual cycle and pinpointing the time of ovulation.

If you are experiencing Mid Cycle Spotting, click to read Mid Cycle Spotting: Causes and what you can do about it

Always consult your doctor for medical advice.

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Linda Ryan- Founder of MARA Fertility Acupuncture Clinic

Hi, I’m Linda Ryan, Fertility Acupuncturist & mother of three: Having overcome my own fertility issues is what drives me to help women like you to achieve the results that I made happen for myself.