The Rhythm Method requires planning, but if you're committed to natural contraception, these apps can help

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Eager to find a form of contraception that doesn't result in mood swings or negative side effects? Going back to the basics may be exactly what you need. (Another reason to switch? To avoid The Most Common Birth Control Side Effects.)

Natural family planning (NFP), also known as the rhythm method, is a form of birth control that involves tracking your body's temperature and cervical mucus to determine the days of the month you're most likely to get pregnant. It's as easy as it sounds: "Each morning when you wake up, you take your daily basal body temperature with a special thermometer," explains Jen Landa, M.D., an ob-gyn and hormone specialist in Orlando, FL. Why? Your basal temperature typically falls between 96 and 98 degrees before you ovulate. After you ovulate, your temperature will rise a bit, usually less than one degree, she explains. You're most likely to get pregnant two to three days before your temperature peaks, which is why tracking yourself for several months and discovering a pattern is necessary when using NFP as a form of birth control, says Landa.

You'll need to check your cervical mucus daily, too, so you can monitor the changes in color and thickness over the course of the month. (Not sure what normal looks like? 13 Questions You're Too Embarrassed to Ask Your Ob-Gyn.) Here's what to look out for: Once your period is over, you'll experience several days where no mucus is present-these are days where you are not likely to get pregnant. As ovulation draws near-meaning an egg is getting ready to be released-your mucus production will increase and often change to a cloudy or white color with a stickier feel, says Landa.

Women typically produce the most mucus right before ovulation, and that's when the consistency becomes clear and slippery, similar to raw egg whites. It's during these "slippery days" when you're most likely to get pregnant. It's crucial to chart your changes throughout the month, so you can be aware of when you should or shouldn't be having sex-if you are looking to have sex during your fertile days and don't want to get pregnant, wear a condom, she adds.

NFP clearly comes with risks. "It's really only appropriate for women who would not be devastated by having a baby," says Landa. The Centers for Disease Control and Prevention reports that NFP has a failure rate of 24 percent, meaning one in four women get pregnant using this as contraception. When you compare that figure to an IUD (0.8 percent failure rate) and the pill (9 percent failure rate), it's clear why accuracy with tracking your cycle is critical. (Be prepared! Check out these 5 Ways Birth Control Can Fail.)

As you can see, NFP requires a lot of attention-and a strong stomach-but there are ways to make it easier. These upgrades bring the ade-old birth control method to the 21st century, allowing you to retire your pen and paper and better monitor your fertility month-to-month.


Daysy is a fertility monitor that learns and tracks your menstrual cycle with a special thermometer synced to their app. Every morning you pop the thermometer under your tongue to take your basal body temperature and Daysy's special algorithm calculates your fertility status for the next 24 hours. By regularly syncing your results with daysyView (the monitor's app) you can easily access your data and see what days you should and shouldn't have sex without extra protection. Daysy's color-coding system makes it super simple to know where you stand: Red days are when to plan for a baby, green days you're in the clear to have sex without worrying about becoming pregnant, and yellow days means the app needs to learn more about you before reaching any conclusions. (While the Daysy thermometer retails at $375, the free daysyView app can be used as a standalone tool for fertility calendaring.)


Clue is a free app for both iPhone and Android that allows you to keep track of your monthly cycle by entering information about your period, menstrual pain, mood, fluid, and sexual activity. The app uses an algorithm to calculate and predict your own unique cycle, and the more consistent you are with your updates, the more accurate your reading will be. Unlike Daysy, the app is not designed to tell you when you are and are not fertile. But it's ability to save personal notes means you can use this app as a paperless way to track the changes you see in your body every month.


iCycleBeads works a little differently than other NFP apps: All you have to do is enter the start date of your most recent period and iCycleBeads will automatically show you where you are in your cycle, and display whether or not today is a fertile day or non-fertile day. The app literally takes the legwork out of NFP because it automatically sends you daily updates, as well as "period reminders" in case you forget to input your cycle start date in any given month. iCycleBeads is also free for both iPhone and Android.