Period Tracking 101: What to Know About Your Cycle

Emily Boynton Fact Checked
Phone and timer with red sand
© Tatjana Zlatkovic / Stocksy United

You measure your water intake, count your steps and monitor your heart rate — but how well do you understand your menstrual cycle? 

Despite being a monthly occurrence, it’s easy to lose track of when your period is due or what symptoms you experience throughout the month (especially if you use birth control that suppresses bleeding). 

An easy solution? Tracking your period. 

Whether you’re tired of surprise visits from Aunt Flo or you want to get a handle on symptoms (looking at you, mood swings) tracking your cycle can help you get in touch with your body and take control of your health.  

Why should you track your period? 

Period tracking is like a multitool for monitoring your health. It can help you track fertility to achieve pregnancy, act as birth control, keep tabs on potential health concerns and provide insight on symptoms like cravings, pain and changes in libido and mood. 

In other words, it helps you see patterns and learn what’s normal for your body. This way, you can prepare for any gnarly premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD) symptoms and increase or decrease your likelihood of pregnancy based on your goals. 

Monitoring your cycle also helps you note any changes, like spotting throughout your cycle or an unusually long cycle, that can be red flags for larger health issues like polyps and fibroids or, in rare cases, precancer or cancer. 

“It is quite helpful to have the regular physical signs of menses to track as first clues about a system imbalance,” says Dr. Ali Lewis, an OB-GYN who sees patients at UW Medical Center – Northwest. “By tracking your cycle details, you can pick up on subtleties that can help you and your healthcare provider diagnose potential problems or help you in avoiding or achieving pregnancy.” 

What should you expect and track during each phase of your period? 

So, you’re on board with the idea of tracking your period. But how do you actually do it? 

The average menstrual cycle is 21 to 35 days long, Lewis says. During this time, your brain (specifically the pea-sized pituitary gland at the base of your brain), ovaries and uterus are a part of a hormone feedback loop that controls your menstrual cycle and prepares you to either conceive or menstruate. 

You can track your cycle using an app or go the old-fashioned route with a pen and calendar. At bare minimum, you’ll want to note the day you start your period, but you can also include things like symptoms, cravings and sex drive to give you a fuller picture.   

Ready to get started? Here’s what to know — and track — during each phase of your cycle. 


Day one of your cycle is the first day you bleed.  

“Each menstruation or period is the lining of the uterus — blood, mucous and other cells — being shed. It lasts on average three to seven days,” says Dr. Kelsey Petrie, a fellow in the Department of Gynecology and Obstetrics at UW School of Medicine.  

Menstruation occurs because of a drop in the hormone progesterone and can cause a range of symptoms, including muscle cramps, back pain, mood swings, bloating and cravings.  

What to track: 

Jot down the first day of your period so you can predict when your next period will come and notice any irregularities in cycle length.  

Tracking additional symptoms like heavy bleeding or cramping will further help you notice patterns and can help you and your doctor find lifestyle changes and treatments to cope.  

Follicular phase 

Technically the first phase of your menstrual cycle, the follicular phase also starts on day one (simultaneously with menstruation). The duration of the phase can vary, but on average it takes about seven to 21 days, Lewis says. 

During this phase, the pituitary gland in your brain sends a signal to release a follicle stimulating hormone that causes your ovaries to produce small sacs called follicles (hence the name of the hormone) that will later release an egg during ovulation. You also experience a boost of estrogen as the follicles mature. 

Post-menstruation, this phase is your time to shine. For many people, this is a time of increased energy and the phase that they’re feeling their best, Lewis notes.  

What to track: 

Tracking vaginal discharge and cervical mucous during this phase can help you determine what is normal for your body. You’ll also want to note if you have any spotting, as this is not expected during the follicular phase and is worth checking up on.  


Ovulation typically occurs around day 14 of the menstrual cycle, Petrie says. 

“For most women, ovulation will be within four days before or after the midpoint of their cycle. In this way, tracking periods and knowing your average cycle length can help predict timing of ovulation,” she explains.  

During ovulation, the egg (now released from the follicle) detaches from the ovary and travels down the fallopian tube, where it can be fertilized for the next 24 hours, aka the fertile window. 

Some people do not experience symptoms during ovulation, though others might have some pain on one side of the body or notice an increased sex drive. 

What to track:  

Folks trying to achieve or avoid pregnancy: This one’s for you. You want to track what days in your cycle ovulation occurs so that you can either have or abstain from sex during your fertile window when you’re most likely to get pregnant.  

To do this, focus on charting your period, take your basal body temperature using a sensitive thermometer (it will rise slightly during ovulation) or use an ovulation predictor kit, which will test your urine for hormones that spike right before ovulation.  

A word of warning for those using period tracking as a form of birth control: It’s essential to track your period correctly and consistently. When used effectively, only one to five out of 100 women become pregnant in their first year of period tracking. However, if you don’t accurately track your period, 12 to 24 women out of 100 become pregnant.   

Luteal phase 

Next up is the luteal phase, in which the follicle (which was left behind by the egg back in ovulation) becomes the corpus luteum, a mass of cells in your ovary that release progesterone and further prepare your uterus for implantation of a fertilized egg.  

“These hormone changes cause the lining of the uterus to stop thickening and to instead prepare for a potential pregnancy,” Petrie says. 

The changes are also responsible for all those less-than-pleasant PMS symptoms, like bloating, mood swings, headaches and breast-tenderness. In addition, activity in cells of your uterine lining can cause inflammation and uterine cramping. 

The luteal phase lasts for about 14 days. If the egg is fertilized and implanted in your uterus, the changes in this phase help your body support pregnancy. If not, the corpus luteum is reabsorbed, progesterone levels fall and your cycle restarts with menstruation, Petrie says.  

What to track: 

Tracking the length of your luteal phase (characterized by vaginal discharge and elevated temperature) can help you better predict when your period next will start.  

It’s also helpful to track sleep, mood, cravings and other symptoms during this phase, as this can help you determine if you are experiencing PMS or PMDD — more than 90% of women report symptoms of the former and up to 3-8% are diagnosed with the latter — as well as find ways to prepare for and cope with specific symptoms.   

When should you talk to your doctor about period symptoms?  

As a rule of thumb, you want to talk to your doctor if you experience something out of the ordinary for your cycle or that prevents you from engaging in your regular activities. 

This can include spotting throughout your cycle, long or irregular cycles (particularly if your periods were previously regular), new symptoms from birth control, or significant or debilitating pain with your period, Petrie says. Noting any changes in mood, such as increased irritability, low motivation, depression or suicidal thoughts will help your doctor determine if you have premenstrual syndrome or premenstrual dysphoric disorder — as well as how to cope. 

If you’re having difficulty conceiving (or conversely are worried about getting pregnant), it can also help to reach out to your doctor about any symptoms you are having and what options are available to help.  

Knowledge is power, and knowledge about your menstrual cycle can empower you to advocate for yourself and meet your health goals. 

“Being aware of how you typically feel across your cycle may be a way to feel more prepared and to manage certain symptoms,” Petrie says. “It can help you know why you may be feeling the way you are feeling, to be kind to yourself and to seek out additional support if needed.”