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Each Phase of Your Cycle, Decoded

Photo Credit: Skims

When you hear the phrase “cycle” do you immediately think of your “menstrual cycle,” aka your period? If so, you’re not alone. For most of us, education on our female hormones is surface level–at best–and we’re left to believe our cycle is as simple as “you’re on your period, or you’re not.” Of course, it’s more complex than that. 

To help us understand all the phases of our cycle (spoiler alert: there are four), we caught up with Dr. Caitlin O’Connor, a Naturopathic Doctor who specializes in holistic treatment for women and children. As she summed it up, “it’s wild in there,” and “when people aren’t paying attention to their cycle it feels like all these random things are just happening to them and they don’t know why.” 

But, she explains, “when you have this information and can put things into context it is so empowering.” Through this understanding, your thoughts shift to, “‘I’m not making this up. I’m not being crazy. These are real physiologic changes that are impacting the biochemistry of my body and are going to have systemic effects,’” Dr. O’Connor says. 

So, let’s get into the nitty gritty–read on for each phase of your cycle, decoded. 

To begin with a broad stroke, Dr. O’Connor explains that we can break the cycle down into two broad categories: 

  1. Preovulatory, or the follicular phase
  2. Postovulatory, also known as the luteal phase

The follicular phase can be considered a growth phase–a revving engine if you will–which reaches a crescendo with ovulation and cools off through the luteal phase preceding menstruation. 

Follicular Phase 

The term “follicular” refers to the follicles, which are small, fluid-filled sacs in the ovaries. Each follicle contains one immature egg and there are thousands of follicles in the ovaries. During the follicular phase, “the brain sends a message to the ovaries–via a hormone called follicle stimulating hormone, or FSH–that brings a pool of those eggs out of hibernation every month,” Dr. O’Connor explains. “This cohort of follicles has been slowly maturing over the last three to four months, and then eight to 20 of them become fully mature during the follicular phase of the menstrual cycle. Of the follicles that mature, one of them becomes what’s called the dominant follicle,” Dr. O’Connor explains.

Follicle-Stimulating Hormone (FSH)
Helps control the menstrual cycle and stimulates the growth of eggs in the ovaries.

“As that egg is chosen, the other follicles stay the same size and the dominant follicle grows and grows and produces more estrogen.That estrogen, when it reaches its peak, triggers a release of what’s called luteinizing hormone, or LH. When people are using ovulation strips to test, they are measuring the luteinizing hormone–the hormone that is secreted by the brain that triggers the release of the egg from the follicle.”

Luteinizing Hormone (LH)
LH helps control the menstrual cycle and triggers the release of an egg from the ovary.

Interestingly, the follicular phase can be variable in length for each person. “So, for example, people with PCOS or other imbalances spend a long part of their cycle in the follicular phase.” This is unlike the luteal, or postovulatory phase, which is almost always 10-14 days, Dr. O’Connor explains. 

You May Feel:

  • Energized
  • Optimistic
  • Glowing skin
  • Your sex drive may be increasing


Once “estrogen reaches its critical mass and triggers the spike of LH, LH then triggers the release of the egg from the follicle,” which is known as ovulation, Dr. O’Connor explains. This process occurs in 12 to 24 hours. “Rising estrogen levels will cause the cervix to make fertile cervical mucus. Peak cervical fluid is visible three to five days before ovulation, because that fluid is what keeps sperm alive to meet their egg,” Dr. O’Connor explains.

“During ovulation often times  libido is higher, energy is higher, creativity is higher, mood is at its best, all because nature’s trying to trick you into going out and making a baby,” Dr. O’Connor says. Mother nature’s manipulation–the original pushy grandmother?

You May Feel:

  • Confidant
  • Optimistic
  • High libido
  • High energy
  • High creativity

Luteal Phase 

Once ovulation occurs we enter the postovulatory, luteal phase, which is usually 12 to 14 days. “The luteal phase gets its name because once the follicle releases the egg, there’s a leftover structure that is called the corpus luteum,” Dr. O’Connor says. “The job of the corpus luteum is to produce progesterone. One of the main purposes of progesterone is to cause appropriate blood flow and nourishment to that uterine lining, with the point of that being, if there’s a fertilized egg it has a home to go to,” Dr. O’Connor explains.

A hormone released by the corpus luteum that stimulates the uterus to prepare for pregnancy.

Estrogen also remains in the hormonal mix at this time. “One of the main purposes of estrogen is to build a thick uterine lining, so estrogen lays down the bricks of the uterus, and progesterone lays down the cement,” Dr. O’Connor explains. 

This hormone stimulates a thickening of the lining of the uterus, known as the endometrium, to prepare your body for a potential pregnancy.

“During the majority of the luteal phase progesterone is rising, but during the second part of this phase progesterone levels start to dip and often people will be more moody, more fatigued, and maybe less inclined to be social. Progesterone is a calming hormone, ideally, so it’s normal for people to feel a little more tired,” Dr. O’Connor explains. “It takes extra calories to build a uterine lining, so some people will notice that they are hungrier during their luteal phase,” Dr. O’Connor advises. “Try to balance the blood sugar and eat more protein and complex carbohydrates during the luteal phase as it can be helpful with sugar cravings,” she suggests. 

Two to three days before our menstrual cycle–when the body gets the message no egg has been fertilized–the biggest dip in estrogen and progesterone occurs, which is when many people can experience PMS symptoms. Surprisingly, these symptoms are tied to the brain adapting to lower hormone levels, which is a big component in PMS, Dr. O’Connor says. 

You May Feel: 

  • Lower energy
  • Moodiness
  • Fatigue
  • Increased appetite
  • PMS symptoms may begin

Menstruation, or Menses Phase

Finally we come full circle, back to our friend, menstruation. Assuming pregnancy has not occured, hormone levels drop and the body works to shed the uterine lining it so dutifully built up over the past cycle. This also triggers the production of hormone-like prostaglandins, which cause your uterus to contract, thus causing your period. A “normal” period can range from three to seven days, and tend to shorten and become more regular with age. 

A group of lipids that control processes such as inflammation, blood flow, the formation of blood clots and the induction of labor.

“Typically during the menstrual flow, that’s a time when people might be more fatigued, especially if they’re low on iron and zinc,” Dr. O’Connor advises. 

You May Feel:

  • Moodiness
  • Have trouble sleeping
  • Increased appetite
  • Cramps
  • Bloating
  • Tenderness in the breasts
  • Acne

Did we check off all of your cycle questions? Anything else you’d like us to explore further here? Drop us a line on social to share your thoughts. Plus, shop OB/GYN-founded vitamins targeted to your exact reproductive stage now.

Jessica Lopez is a writer and new mother based in Southern California. She has covered everything from bridal to wellness for BRIDES, Byrdie, THE/THIRTY and more, and she currently enjoys (over)thinking and writing about parenthood. You can connect with her on Instagram

This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and we recommend that you always consult with your healthcare provider. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of Perelel.