Understanding Your Menstrual Cycle: The Basics
Learn about the basics of your menstrual cycle in today's post, including the various phases and hormone changes that occur.
Besides getting our period each month, many of us don't think too much about our menstrual cycles, let alone what "phase" we might currently be in. But knowing this information can provide helpful insights into why you might be feeling a certain way and what you might need to help you feel your best.
Having a good understanding of the inner workings of our body can help us get to know ourselves better. Hormones play a big part in everyone's bodies, but for women in particular, there are lots of fluctuations going on inside of us through the month. Sometimes our estrogen levels are higher, sometimes they're lower. Sometimes we have a high sex drive, other times we don't. Sometimes we feel anxious, irritable, tired, or have tender breasts, other times we feel energetic, productive, and all around good.
While there are so many different factors at play when it comes to how we feel on any given day, our hormones and menstrual cycle can be a big part of the picture!
In today's post I'm covering the basics of the menstrual cycle. I'll be talking about what's considered "average" or "normal", but please know that everybody is very different and no two menstrual cycles or periods are the exact same. This is especially so if you have a medical condition or are taking medication such as the birth control pill that affects your cycle.
Your Menstrual Cycle
A normal menstrual cycle lasts anywhere from 25-35 days, with a period that lasts between 3-7 days. A "cycle" is the time from the first day of your period to the first day of your next period.
The menstrual cycle consists of 3 specific phases: follicular, ovulation, and luteal. These phases are controlled and orchestrated by a group of different hormones, including:
• Gonadotropin releasing hormone (GnRH) from the hypothalamus
• FSH and LH from the pituitary gland
• Estrogen and progesterone from the ovaries
Follicular Phase
The first day of your period marks day 1 of your cycle. Menstruation lasts an average of 3-7 days. This is your monthly bleeding and is caused by the lining of your uterus shedding.
This is also the very beginning of the follicular phase, which is the stage when your body is preparing to release an egg (ovulation). The follicular phase ends when you ovulate, and is approximately 14 days long, however, it can vary each month. Some months it may be shorter or longer, such as 12 days or 18 days. The length of your follicular phase determines how early or late you menstruate in a given cycle. So the longer your follicular phase, the longer your overall cycle will be (e.g. 26 days vs. a 32 day cycle)
At the beginning of the follicular phase (also the start of your period), estrogen and progesterone levels are low. Estrogen becomes the dominant hormone in this phase as it increases gradually until ovulation occurs, around the middle of your cycle. This gradual increase of estrogen is what thickens the lining of the uterus. Additionally, follicle-stimulating hormone (FSH) released by the pituitary gland leads to the development of a mature egg in the ovary. Once estrogen levels reach their highest right before ovulation, FSH is suppressed and luteinizing hormone (LH) is secreted by the pituitary gland. This increase is a fundamental part of ovulation and is known as the "LH surge".
Toward the end of this phase (right before ovulation), high levels of estrogen prepare the uterus for a possible pregnancy. The lining of the uterus (also known as the endometrium) thickens and glands in the cervix produce copious amounts of a stretchy, jelly, egg-white-like mucous to facilitate sperm entry. This is a very specific kind of mucous that we produce for a couple of days that indicates that we are very fertile and most likely to get pregnant if we have unprotected sex.
What You Should Know About This Phase
During the follicular phase, especially at the beginning when you first get your period, you may be crampy, bloated, or tired. Your energy levels may be a little lower during the follicular phase until estrogen starts to peak closer to ovulation.
You may feel a sense of relief or be in a better mood at the start of, and throughout this phase, as PMS symptoms diminish
It's a great idea to add in some iron-rich foods into your diet in this phase. Blood loss from menstruation can result in lower iron levels, so enjoy foods like beans, lentils, dark leafy vegetables, red meat, fish and poultry
Keep an eye out for that stretchy, jelly-like mucous that resembles raw egg white, around the middle of your cycle. This indicates that ovulation is about to occur.
Ovulation
During ovulation, about 16-24 hours after LH peaks, an egg is released into the Fallopian tube from the mature follicle, and carried away to be fertilized or to die.
An egg at this time is only viable for approximately 24 hours. However, since sperm can survive in the vagina for about 5 days prior to ovulation, our “fertile window” can be around 7 days (typically about 25% of a normal cycle).
What You Should Know About This Phase
Sex drive tends to be higher around ovulation as your body is prepping itself for getting pregnant
Some women feel more productive or energetic around ovulation. If this is you, take advantage of it!
As mentioned above, keep an eye out for that stretchy mucous around this time which indicates that you're fertile. This is helpful to know if you are planning for or wish to prevent pregnancy.
If you are taking hormonal birth control, ovulation does not occur.
Luteal Phase
After an egg is released from the ovary, its follicle develops into the corpus luteum which produces increasing amounts of progesterone and estrogen. Progesterone is the dominant hormone in this phase which continues to prepare the uterine lining (endometrium) for pregnancy. Cervical mucous also thickens due to increased progesterone, which creates a "plug" to block bacteria and sperm from entering the uterus at this time.
The corpus luteum has a life span of about 10-14 days, and if pregnancy did not occur, it will degenerate. Once it degenerates, progesterone levels are no longer high which, combined with blood vessels in the uterine lining contracting and reducing oxygen, causes the cells to die and the lining to shed. This begins another period and menstrual cycle.
Once the corpus luteum dies and progesterone production decreases, cells in the uterine lining slough off which begins day 1 of our cycle all over again.
What You Should Know About This Phase
Many people experience premenstrual syndrome (PMS) in the days leading up to their period. This may include mental or physical symptoms (such as anxiety, irritability, tender breasts, sadness) caused by many factors, including the fluctuations of hormones.
This is a good time to take it easy, talk about your feelings, and get some gentle exercise to release any pent-up irritability or anger. Stay tuned for an upcoming blog post and video all about PMS. I'll be sharing more soon!
I hope you found this overview helpful! I'm passionate about women's health and tuning into our cycles to help us align our actions and lifestyle choices with the changes our bodies experience through the month. I'll talk more about this soon, too.
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