Does This Controversial Birth Control Method Actually Work?

If it feels like you've tried every type of birth control out there and still haven't found something that works for you, then the prospect of an inexpensive, non-hormonal, at-home method probably sounds pretty ideal. And yes, this type of birth control actually exists, but there's kind of a catch.

Called the "rhythm method," this fertility awareness form of birth control involves tracking your period to calculate when you ovulate, according to Planned Parenthood. It's been around since the 1930s, but it's making a comeback both with people who are seeking an alternative to hormonal birth control, and those trying to get pregnant.

In general, doctors tend to be skeptical about the rhythm method for birth control, simply because in actual use, it's not as accurate or effective as other methods available, explains Margaret Polaneczky, MD, FACOG, an Ob/Gyn at NewYork-Presbyterian/Weill Cornell Medicine. In fact, there's a joke that Dr. Polaneczky likes to tell: "What do you call people who use the rhythm method for birth control?" The answer: "Parents."

Now, this isn't to say that no one should be using the rhythm method, but it requires diligence and really only works for those with a very regular cycle lasting between 26 and 32 days, she says. If you think that might be you, grab a calendar and a calculator, and let's get into how this method works.

First, record the length of six to 12 of your menstrual cycles, from the first day of your period to the first day of your next period, according to the Mayo Clinic. Then, you take the length of your shortest menstrual cycle, and subtract 18 from the number of days to find the first fertile day of your cycle. Next, take the length of your longest menstrual cycle and subtract 11 from the number of days to determine the last fertile day of your cycle. Now that you have this information, you have to plan sex around when you're most fertile — either going hard during those days, if you're trying for a baby, or keeping pants firmly in place if not. To ensure accuracy, it's best to keep updating your calculations every month.