How to track your menstrual cycle

Predict your periods, track your cycles, or try for a baby

With the Clearblue^® Period & Cycle Tracker app.

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Knowledge is power, and understanding your menstrual cycle is a key step in managing your fertility. Tracking your cycle and identifying your fertile window empowers you to take control of your reproductive health.

Knowing when you ovulate is crucial when trying to get pregnant. Tracking your fertility can be tricky, as menstrual cycles vary from woman to woman and even cycle to cycle. We're here to take the guesswork out of cycle tracking! The Clearblue® Period & Cycle Tracker app was designed to help predict your periods, track your cycles, or try for a baby. 

First, a quick health lesson

Day 1 of your cycle starts with the first day of your period (the first day of bleeding). As your body sheds the uterine lining, a process typically lasting three to seven days, the pituitary gland releases follicle-stimulating hormone (FSH). This triggers the growth of fluid-filled follicles on the ovaries, each containing one egg. 

The follicular phase follows, leading up to ovulation. Typically, only one follicle keeps growing and starts to release increased levels of estrogen. Meanwhile, the uterine lining thickens with nutrients and blood in preparation for potential implantation. In a typical cycle, ovulation occurs next. Rising estrogen triggers a surge in luteinizing hormone (LH), causing the follicle to rupture and release an egg into the Fallopian tube, where it survives for 12 to 24 hours.

After ovulation, the luteal phase begins. Your follicle produces more progesterone, a hormone that helps the uterine lining store more blood and nutrients. As the egg travels through the Fallopian tube to the uterus, fertilization may occur.  If fertilized, the egg can implant in the uterine lining, signaling the beginning of pregnancy. 

If the egg is not fertilized, the level of progesterone declines, the uterine lining breaks down and the egg is shed, along with the uterine lining, during your period.

When is your fertility window, and how long does it last?

Sperm can live for up to five days in your body after sex, thanks to cervical mucus changes that create a sperm-friendly environment. Since an egg lives for up to 24 hours, the fertility window spans about six days—covering both sperm and egg viability. Peak fertility occurs the day before and the day of ovulation.

Tracking your cycle with physical ovulation symptoms

As ovulation approaches, cervical mucus becomes clear and slippery, resembling egg whites. Some women experience a one-sided twinge or cramping during ovulation, known as mittelschmerz. After ovulation, basal body temperature—your resting temperature upon waking—slightly increases.

You can always have a quick look online and find free fertility charts to download and print for tracking your physical symptoms but if you prefer a digital option, our new Clearblue® Period & Cycle Tracker app makes it easy to track your cycles on your phone. You can also log your periods, log symptoms and note bodily changes as well as the app predicting your peak fertility days and period due date based on your cycle length. Relying solely on physical changes to track fertility has its challenges. Many women don’t experience ovulation symptoms, or they vary from cycle to cycle. 

Predicting ovulation with the LH surge

The LH surge is key to predicting ovulation, and Clearblue® digital ovulation tests are over 99% accurate in detecting an LH surge. Since ovulation typically occurs 24 to 36 hours after an LH surge, using ovulation tests makes it easier to identify your fertile window.¹

How do ovulation tests work?

Two Clearblue^® tests (Fertility Monitor with Touch Screen and Advanced Digital Ovulation Test) monitor both your estrogen and LH levels, identifying more days when you are fertile, compared with most other ovulation tests. Remember that your estrogen level rises first, followed by a surge in LH level. The Clearblue^® Digital Ovulation Test detects your LH surge, identifying your two most fertile days.

To use an ovulation test effectively, you'll need to know the first day of your last period. Our calculator can help you determine the best time to start testing. When testing, it’s important to use your first urine of the day.  Like a pregnancy test, you’ll either urinate directly on the absorbent tip or dip it into a clean, dry container. Follow the test instructions for timing and result interpretation. Test daily to determine your peak fertility days—once you detect your LH surge, you can stop testing for that cycle and save any remaining tests for the next one.

Not sure which Clearblue® ovulation test to choose? Check out our comparison chart here.

Predicting ovulation: A not-so-old history²
For centuries, the timing of conception was mired in falsehoods, superstitions and misunderstandings. The study and understanding of ovulation is relatively new. Here’s a quick look:

• 1920s to 1930s

  Gynecologists discover ovulation typically occurs around 12 to 16 days before the onset of the next period; tracking basal body temperature first promoted as a natural form of birth control

• 1932

  “The Rhythm of Sterility and Fertility in Women” first published; rhythm method calculators popular

• 1950s

  Cervical mucus changes linked to ovulation

• 1960s

  The Billings Ovulation Method introduced

• 1970s

  The Sympto-thermal method, combining rhythm, basal body temperature, and cervical mucus changes, gains popularity

• 1989

  Clearblue^® launches the world’s first one-step home ovulation test, measuring LH

• 1999

  Two-Day Method and CycleBeads, both based on the Standard Days Method, introduced; Clearblue^® launches the first at-home fertility monitor, measuring estrogen and LH, to identify a wider fertility window

• 2004

  Clearblue^®’s first digital smiley face ovulation test released

• 2013

  Clearblue^® launches the first Advanced Digital Ovulation Test to detect two key fertility hormones

• 2017

  Clearblue^® launches Connected Ovulation Test System, tracking estrogen and LH while syncing to your phone

• 2024

  The Clearblue^® Period & Cycle Tracker App is launched to help women who want to predict their periods, track their cycles or try for a baby  

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