Editor’s Note: We at POPSUGAR recognize that people of many genders and identities have menstrual cycles. This particular story includes language from experts who generally refer to people with menstrual cycles as women.
Fun fact: did you know an average moon cycle lasts around 29 days, just like the average time it takes to complete a menstrual cycle? While technically our bodies don’t follow the lunar calendar — though “luteal phase” sounds pretty similar — knowing about the phases of your cycle is just as important as knowing about the moon and the stars. So if science class didn’t give you the details, it’s time to dive deeper.
The menstrual cycle is a vital sign of overall health. “When it is not ‘right,’ it indicates an underlying health issue is present that requires attention,” Felice Gersh, MD, ob-gyn and author of “PCOS SOS: A Gynecologist’s Lifeline to Naturally Restore Your Rhythms, Hormones and Happiness,” says. “Knowing where you are in the menstrual cycle can help with fertility planning, menstrual planning, and recognizing symptoms.” And understanding the events of the menstrual cycle can help you feel more prepared for it, says Chimsom “Dr. Chimmy” T. Oleka, MD, gynecologist and Knix puberty and period specialist. “The more knowledge one has about their body and the ways in which it changes, develops, and grows, the better they are at understanding, being patient with, being proud of, and appreciating their body,” she says.
It’s important to note not all menstruating people have a period every month. “In fact, it’s completely safe and in many cases a better experience to use contraceptives to skip periods altogether and stay on a steady dose of hormones,” says Erin Flynn, DNP/FNP, a family nurse practitioner with Favor. “Not only does this reduce the stress of bleeding (and for some, pain) every month, it also helps reduce the symptoms many of us experience as our hormone levels change around our periods, such as headaches, mood swings, acne, and cramps.”
The levels of certain hormones like estrogen and progesterone rise and decline throughout the menstrual cycle, making the uterus and ovaries respond in different ways. For example, you might experience headaches, cramp-y discomfort in your lower back or lower abdomen, and even changes in your sleep. POPSUGAR spoke with period experts to better understand what the heck is happening during your menstrual cycle and how to use that information to help you feel better in your body.
What Are the Phases of the Menstrual Cycle?
According to Dr. Chimmy, there are two different cycles within the menstrual cycle that take place at the same time. The ovulatory cycle happens in the ovaries, and the endometrial cycle takes place in the lining of the uterus. These cycles have different phases that pair up with each other as well.
Within the ovary, Dr. Chimmy says there are the follicular phase, ovulation, and the luteal phase. In the uterus, there are the proliferative phase, the secretory phase, and menstruation.
Four commonly referenced events in the menstrual cycle are the menstruation, the follicular phase, ovulation, and the luteal phase.
The first day of full-flow period blood (not just spotting) marks the first day of your menstrual cycle, says Dorette Noorhasan, MD, endocrinologist and infertility specialist. It’s considered normal to bleed between two and seven days during menstruation, according to the Cleveland Clinic, during which the lining of the uterus — called the endometrium — is shed. This occurs if the implantation of a fertilized egg (a pregnancy) doesn’t occur.
The follicular phase is the first part of the menstrual cycle, Dr. Noorhasan says. “In the follicular phase, FSH [follicle stimulating hormone] is secreted by the pituitary gland, which tells the ovaries to produce a mature follicle. As the mature follicle grows in size, it will secrete estrogen, and the estrogen levels will rise,” Dr. Noorhasan says. Higher estrogen levels signal to the pituitary to secrete more luteinizing hormone (LH), which tells the follicle to rupture and release the egg, Dr. Noorhasan adds.
Dr. Chimmy explains that the follicular phase pairs with the proliferative phase, and during this time, “in response to the estrogen, the endometrium regrows after shedding during the previous period.”
Ovulation happens when the mature dominant egg releases from the ovarian follicle, Dr. Chimmy says. As for what day this takes place, it depends on the person and the length of their individual menstrual cycle.
“If you have a regular 28-day cycle, ovulation will often happen day 14 [of the menstrual cycle]. But many women have cycles that are shorter or longer, and the ovulation day will be different for these women. If you have other underlying conditions like PCOS, this will also change your cycle length and ovulation date,” Dr. Shirazian says.
According to the Cleveland Clinic, after the egg is released, it then travels through the fallopian tube to the uterus.
The luteal phase is the last phase of the menstrual cycle and pairs with the secretory phase in the uterus. “Once the egg is released, the follicle now shrivels up and is called a corpus luteum,” Dr. Noorhasan says. The corpus luteum then secretes a hormone called progesterone. This hormone peaks about seven days after ovulation, she adds.
If a pregnancy does not occur, the corpus luteum continues to shrivel up, so it becomes no longer functional and stops secreting progesterone. Without this progesterone, the endometrium will shed, Dr. Noorhasan explains. Once menstruation occurs, the menstrual cycle starts over again.
However, if pregnancy does occur, Dr. Noorhasan says that hormones sustain the corpus luteum, which then secretes more progesterone to support the pregnancy and prevent the endometrium from shedding.
Can the Phases of the Menstrual Cycle Impact How You Feel?
There are many benefits to knowing what your hormones are up to and when. “One of the main benefits is being able to predict when you are going to experience menstrual symptoms like mood swings, cramps, or headaches,” says Flynn. “We all react differently to the hormone changes that come with our menstrual cycle, so being in tune with our bodies and understanding our cycle can help us understand whether we’re moody because of yesterday’s workday, or if it’s just our regularly scheduled hormonal shift.”
If you have ever experienced menstrual cramps, you know first-hand there is a link between your period and how you feel physically. So what are some other possible physical markers of the menstrual-cycle phases?
“During the follicular phase of the menstrual cycle, higher levels of estrogen can make you feel more energetic,” Dr. Shirazian says. Some menstrual-cycle-inspired exercise plans actually suggest more intense workouts during this time, but you should always listen to your body to ensure you don’t injure yourself.
In the luteal phase, some people who menstruate may feel bloated or lethargic, she adds. During menstruation, you may experience some period symptoms like cramps or a change in vaginal discharge. Then during ovulation, Dr. Shirazian notes that some may experience a change in vaginal discharge and spotting. Another physical symptom that some experience during ovulation is ovulation pain, or “mittelschmerz.” According to the Cleveland Clinic, ovulation pain is typically felt in the lower abdomen and pelvis on one side or in the middle, and it may feel like mild twinges or severe discomfort. If you have any questions or concerns about menstrual-cycle symptoms or your menstrual cycle in general, reach out to your healthcare provider for advice.
— Additional reporting by Melanie Whyte