Fertility Calendar

Creating a fertility calendar to help you track fertile days can help pinpoint ovulation for your best chances of conceiving. Keep reading to find out more about your fertility calendar, and how you can get started tracking your fertility cycle.

What is a fertility calendar?

Contrary to popular belief, it’s simply impossible to get pregnant on every single day of the month. That’s because your body times its ovulation — the release of an egg — for one particular day. Don’t worry, that doesn’t mean you’re only fertile for one day, though. Because sperm can survive in the reproductive tract for up to five days after sex, waiting for an egg to be released, this increases the number of fertile days — the days your chances of becoming pregnant are high.

Why is a fertility calendar helpful?

Understanding your unique fertility cycle can help you pinpoint those fertile days, and determine patterns in your fertility. With this information, you can plan when to time sex for the best chances of getting pregnant. After tracking several fertility cycles, you may be able to pick out highly fertile days and use that information to your benefit, or pass along information to your fertility specialist about recognized issues with ovulation. Knowing your fertile window (the time each cycle you are able to become pregnant) can also help fertility specialists approach treatment and assistance options.

It’s important to also know that creating a fertility window doesn’t give you exact dates of ovulation, but is rather an estimate. Your actual fertile days can fluctuate from month to month, but creating a fertility calendar is a great start at determining when you may be able to get pregnant.

How do I get started?

At its most basic, your fertility calendar tracks the length of your cycle, and at what points you menstruate and ovulate. Whether you choose to use an app or good old-fashioned pen and calendar, you’ll want to start by marking the first day of your period. This is considered day one (also called chart day one or CD1). You’ll want to continue marking down each day that you are menstruating. Some women also choose to include the heaviness of their period, cramps, and other menstruation-related information.

Throughout the month, it’s also a best practice to mark down days that you have sex. This can help you keep track when trying to conceive, and can be useful information for a fertility specialist if they choose to review your fertility calendar. Some women also prefer to keep track of PMS symptoms such as cramps, back pain, and headaches so that they can begin to detect patterns of their upcoming period (both for a scientific and personal purpose).

I’ve tracked a full cycle. What comes next?

At the start of your next period, the task of marking down the first day of your period begins again. But, with a completed cycle, you’ll now have a little information to analyze.

Looking back at the cycle prior, you’ll want to count the number of days between the first days of your period. To begin honing in on the day you ovulate, you’ll want to subtract 18 days from the length of your cycle. For example:

  • If your cycle is 28 days long, subtract 18 from 28, leaving you with 10 days.

Next, you’ll use this number to count out from the first day of your period and mark this day with an X. The date you land on is the first possible fertile day of your cycle.

  • If day 1 was on the 5th day of the month, you’ll count 10 days from the 5th, which lands on the 14th day of the month. Mark this date with an X.

You’ve now determined the start of your fertile window, but you’ll also need to predict when it will end. To do this, you’ll want to subtract 11 days from the length of your cycle.

  • If your cycle is 28 days long, subtract 11 from 28, leaving you with 17 days.

Then, you’ll use this number to count out the days from the first day of your period. Mark this date with another X — it represents the end of your fertile window, or the estimated time you are able to get pregnant.

  • If day 1 was on the 5th day of the month, you’ll need to count 17 days from the 5th, leading you to land on the 21st.
  • This means that, in this example, your fertile window falls between the 14th and 21st days of the month.

Looking back at your calendar, you’re now able to see the dates you had your period, as well as your possible window of fertility. If you’re looking to conceive, you’ll want to time sex during this window. Or, if you’re using some form of reproductive medication that’s based on ovulation, this information can help you and your fertility specialist determine the best times to begin a drug or time a fertility procedure.

Because each cycle is different, even with the same woman, it’s smart to continue tracking the days of your period. Each month, the information becomes more helpful because you’ll be able to detect patterns with your cycle length, and can adjust your fertile window accordingly. To do so, after tracking for several months, you’ll want to adjust the start of your fertile window based off the shortest cycle you’ve had, and the end of your fertile window off the longest cycle.