How effective is the rhythm method?

Not so much.

Instead, I simply fell back on the good ol’ withdrawal method and abstained during what I thought were my most fertile days. (I also had it in my head that breastfeeding suppressed ovulation, which isn’t exactly accurate.) Needless to say, my two children are 17 months apart.

You’d think the whole experience would have turned me off to natural contraception entirely, but I’m actually among a growing number of young women interested in non-hormonal birth control. The trend is on the rise, according to a recent CNN report. While I’ve since opted for a hormone-free IUD, more and more women are giving natural contraception a whirl.

The idea, which can take a variety of forms, is basically a ramped-up approach to the traditional rhythm method.

“The rhythm method is definitely not how we refer to it anymore,” says Kristina Tocce, MD, an OB-GYN and associate professor at the University of Colorado Anschutz Medical Campus. “We call it fertility awareness-based methods, and there are a number of different ways to do that.”

Tocce notes that both the World Health Organization and the CDC recommend counseling patients on most effective to least effective birth control methods—in that order. Statistically speaking, that puts fertility awareness-based methods at the bottom of the heap.

“Even when you have the most motivated patient who really keeps track of everything, there’s still a 12 to 24 percent failure rate for fertility awareness-based methods,” she says. But she adds that there also haven’t been any recent, large-scale, high-quality trials really examining the approach.

So what do fertility awareness-based methods entail? Tocce says that the most popular types involve some variation of counting days. This typically relies on the woman knowing her cycle well enough to either use a back-up method or abstain altogether during her fertile days, which are commonly days eight through 18 of her cycle.

Other popular approaches incorporate basal body temperature, which usually increases when a woman is fertile. The body also reveals other little clues that mark fertility.

“Women have to note the presence or absence of certain [vaginal] secretions,” says Tocce, adding that these secretions change when a woman is most fertile. “So patients have to be willing to do all that legwork and really keep track of everything.”

According to Tocce, the most effective forms of birth control include reversible implants, like IUDs, and permanent sterilization. These methods result in less than one pregnancy per 100 women per year. Hormonal methods like Depo-Provera injections, birth control pills, the patch and the ring come in second, resulting in six to 12 annual unintended pregnancies for every 100 women.

There are other benefits to hormonal birth control, Tocce says.

“For patients who don’t have a family history of cancer, I really let them know that using birth control pills can decrease their risk for endometrial cancer because it suppresses the endometrial lining, so the risk for hyperplasia and endometrial cancer should be lower in those patients,” she says. “It also reduces the risk for ovarian cancer, which is a rare cancer but any method that suppresses ovulation will decrease ovarian cancer risk, so it has that benefit as well.”

Condoms represent the go-to contraception for many, but they aren’t perfect. Despite popular belief, they’re considered a third-tier method. Tocce adds that the failure rate with typical use is about 18 percent. (There’s a 2 percent failure rate with perfect use.)

At the end of the day, there’s a margin for error with any form of contraception. Even so, it falls on healthcare providers to give women a comprehensive overview of all the options.

“If a patient came in and a fertility awareness-based method was really what she desired, and we went over everything else and that continued to be what she desired, I absolutely would support her with that choice,” says Tocce.