Understanding Your Menstrual Cycle

by Emily Pomfrey Wells, MS - dietetic intern

 
 

Understanding your menstrual cycle is important for your physical, mental and reproductive health. This blog will provide you with information to improve your cycle knowledge. 

There are different ways to think about the phases of the menstrual cycle. Often the menstrual cycle is divided into four phases: menses, follicular, ovulation and luteal; each cycle is the result of different messages being sent by various hormones throughout the body. The cycle can also be thought of in two distinct phases: follicular phase and luteal phase. 

If we think about the menstrual cycle in four phases it often looks like this:

Menstruation

Day one of the menstrual cycle begins on the first day of your period and most commonly lasts three to five days, some individuals will experience bleeding for a longer period of time. During your period it is within the normal range to lose 2 to 3 tablespoons of blood, some women experience greater blood loss during this time. It is normal to experience mild to moderate cramps during one or two days of your period and severe pain could be caused by endometriosis, PMDD, adenomyosis, or uterine fibroids, and warrants additional follow up with your doctor. 

Ovulation

For many at or around day 14 ovulation will occur. This is when the egg is released from the follicle into the fallopian tube, and is the result of an increase in luteinizing hormone. This is when peak fertility happens, however, the “fertile window” is actually a 5 day period including 3 days prior to ovulation, the day of ovulation, and the day after. This is because sperm can survive in the uterus for 5 days, but an egg only survives 24 hours after ovulation if it is not fertilized.

 

Follicular Phase

This phase happens on day six through fourteen, estrogen increases and follicle stimulating hormone causes follicles to grow, one of these follicles will become an egg during ovulation. For those with PCOS or during an anovulation phase related to other hormone imbalances, stress, over exercising or other medical conditions, a follicle may not develop into an egg. 

 
 

Luteal Phase

The last phase of the menstrual cycle is the luteal phase, taking place from day fifteen to 28. During this phase progesterone levels increase with the intention of preparing the uterine wall so the fertilized egg can attach. If the egg isn't fertilized then levels of estrogen and progesterone drop which cause the lining of the uterus to shed and the menstrual cycle to restart. The last week of the luteal phase is often when symptoms of PMS begin.

The big takeaway is that during the menstrual cycle, there are varying levels of hormones sending messages to help keep your reproductive health on track. 


Menstrual irregularities such as a shorter or longer menstrual cycle, luteal phase deficiency, and amenorrhea, which is the absence of a menstrual cycle, can be caused by PCOS, stress, undereating and excessive exercise.

Luteal phase deficiency is the result of insufficient amounts of progesterone being released from the ovaries and impacts the uterine lining’s ability to thicken and shortens the length of the menstrual cycle after ovulation. One root cause of luteal phase deficiency is undereating and overexercising. Read this blog to learn how to increase your progesterone through adequate nutrition.

Undereating, over exercising and/or being underweight for your body’s set point can impact your body's ability to ovulate and have a menstrual cycle, which is also known as hypothalamic amenorrhea (HA). This is because reproductive hormones are stored in body fat, and without adequate amounts your body cannot produce enough of the hormones it needs for a regular cycle. However, you don’t have to have a low BMI to have HA; an energy imbalance can cause loss of menses in any size body. HA is common in athletes, but is NOT normal. Losing your period as a result of over exercising is a sign that you are not eating enough to support your training load and can have long term health consequences such as reduced bone mineral density, decreased immune function and decreases in athletic performance.

Hormones affected by PCOS can change the length of the menstrual cycle by inhibiting or delaying ovulation. Undereating and overexercise can worsen symptoms of PCOS by adding stress to an already inflamed body. They can also trigger a binge-restrict cycle, which can worsen insulin resistance, which is the root cause of most cases of PCOS. The Insulin Resistance Mini Course is one great resource for those trying to conceive with PCOS.

Do I need to seed cycle?

We busted seed cycling myths on the previous blog but here is a quick recap. Seeds are great for hormonal health but there is weak scientific evidence to support eating certain seeds at certain times of the month. Instead try eating a variety of seeds and nuts regularly throughout the month to help balance blood sugar, reduce PMS symptoms and boost fertility. 

Should I cycle-sync my workouts?

There is also a limited amount of scientific evidence to support changes in sports performance or ability to build mass and strength at different phases of the menstrual cycle. Our recommendation is to listen to your body throughout the month, take into account how you feel at different phases throughout your cycle, and choose movement that feels good to you (and that you enjoy!) regardless of where you are in your monthly cycle.

Can nutrition reduce PMS and period pain?

For most of us, feeling good throughout our cycle comes back to the basics: adequate nutrition, hydration, sleep, stress management and moderate physical activity. Focusing on these factors throughout the month can improve hormonal health, improve fertility and reduce PMS symptoms. Whether it’s PMDD, endometriosis, fibroids, or adenomyosis, adding nutrient dense foods to your diet, and most importantly, eating ENOUGH, can greatly reduce period pain and heavy bleeding.

Need support in improving your cycle health? Feed Your Zest offers 1:1 nutrition counseling as well as group coaching through Fully Nourished Pregnancy and the Insulin Resistance Mini Course. Click on the links to learn more!