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A new fertility tracking app, Dot, is billing itself as form of contraception — and touting the results of a new efficacy study that shows the app may be up to 99 percent effective as a form of birth control.

With statistics like that, Dot — part of a surge in fertility and contraception apps — would appear to be one of the most effective birth control tools available.

But there’s also significant debate over how to measure the effectiveness of these tools, as well as questions about which apps should be available in the first place. Although Dot is being touted as a form of contraception, it has not yet undergone a Food and Drug Administration clearance process intended to evaluate and authorize such claims.


“Doctors and patients need to be talking about these apps,” said Dr. Nathaniel DeNicola, an OB-GYN affiliated with George Washington University and the chair of telehealth for the American College of Obstetricians and Gynecologists, who is not affiliated with Dot. “For some women, this method may be perfectly acceptable. … But they need to know what they’re getting into.”

Cycle Technologies was founded in 2002 — well before smartphones existed. One of the company’s first products was CycleBeads, a fertility-tracking bracelet that’s based on a precalculated and fixed “fertile” window; a small ring that’s moved around the bracelet reminds people where they are in a given cycle. CycleBeads is based on the work of Victoria Jennings, the director at Georgetown’s Institute for Reproductive Health — who is also the mother of Cycle president Leslie Heyer.


“I grew up hearing about this space a bit,” Heyer quipped.

Unlike Natural Cycles, Dot does not use basal body temperature measurements as part of its system. Instead it relies on an algorithm that uses Bayesian statistics to adjust as women add more data about their menstrual cycles to the app. The app gives users a window of about 11 to 13 days during which they should use a condom or another birth control method to prevent pregnancy.

Dot’s app makes several overt references to its potential use as a contraceptive. In the frequently asked questions section of the the Apple version of the app, the company states that “Dot can be used as birth control.” It also explicitly asks users during setup if they’re using the app to prevent pregnancy, plan a pregnancy, or just track their cycles. It also claims that its algorithm is “is the most advanced approach to accurately calculate your conception chances by day.”

Monday’s study claims that Dot, which uses information about a person’s menstrual cycles to calculate when they are most likely to be fertile, is up to 99 percent effective with perfect use and up to 95 percent effective with typical use. For the purposes of the study, “typical use” meant using a condom on the app-identified “fertile” days — a combination that makes it difficult to compare how effective it truly is relative to other common methods of birth control.

The study, published in the European Journal of Contraception and Reproductive Health Care, showed that 25 of 718 people got pregnant during the study, which lasted more than 20 months. Only one of those people reported she had always used a condom during the fertile period.

DeNicola highlighted another statistic in the study: 10.3 percent.

That was the “worst-case” scenario effectiveness rate calculated in the study, which assumed that 33 people who didn’t respond to follow-up inquiries and were potentially pregnant were actually pregnant.

“It’s great that we’re looking into these things. … But given how important the outcome is, we need to be the most conservative in this area,” he said.

Not every part of the app makes it clear that using a backup method for a considerable part of a person’s cycle is necessary to use the app correctly.

“Extensive analysis and scientific research indicates Dot is accurate and effective. All you need is Dot the app!” the app says in a Q&A entry.

When STAT asked about that entry, Heyer said the company would take another look at that section — which would be updated with the study’s results anyway. “If you look through our FAQs, and even on the main page where Dot tells you if you’re on a high-risk day, it does say, ‘Use protection,’” Heyer added.

The company has not yet gone through the FDA process required to market contraception apps like the high-profile app Natural Cycles, which also tracks fertility through a user’s smartphone and which the FDA cleared in August.

Dot’s manufacturers say they plan to apply for FDA clearance — but despite the fact that contraceptive apps fall into a category that would require that clearance before an app hits the market, they haven’t yet. Dot is currently available for both Apple and Android devices.

“We are going to do our absolute best to comply,” Heyer said.

FDA spokesperson Deborah Kotz noted in an email to STAT that the agency cannot comment on specific products that have not gone through the FDA’s review process, but confirmed that “software apps intended to prevent pregnancy are considered class II devices that are required to undergo FDA premarket review before being marketed.”

The agency also has some “special controls” for contraceptive apps; any new FDA-cleared apps in that category will have to show data from clinical performance testing and human factors and usability testing, among other things, as part of a clearance application.

Just because the FDA has the power to regulate an area doesn’t mean it always does. The agency has “enforcement discretion” to ignore some things that might otherwise be scrutinized. The only fertility-related apps that have officially been spared the agency’s review are apps meant to plan pregnancies — not ones meant to prevent them.

Cycle has hired an FDA consultant to help with Dot’s application, Heyer said, noting that the agency’s approach to contraceptive apps has “really evolved very quickly.”

“I know other people in the fertility awareness space who have spoken with [the agency], and in the past they were not interested. That obviously has changed,” she said. “When Natural Cycles got their FDA [clearance] a few months back, we sat up.”

Heyer and DeNicola both noted that incorrectly using an app as contraception — FDA cleared or not — can have life-changing consequences.

“There are very few [apps] that are actually designed for pregnancy prevention,” Heyer noted. “I think a lot of people are using these sort of general trackers … and turning around and using them to prevent pregnancy. And that is really scary,” Heyer said. “I think it’s a real public health issue.”

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