Natural Cycles unveiled the results of a study of 54,000 women. Here’s what it found.
Natural Cycles found that its app is roughly 93 percent effective.
When the U.S. Food and Drug Administration approved its first contraception app, the developers had shown that Natural Cycles was 93 percent effective with typical use. But was that figure accurate for different populations?
To find out, Natural Cycles and industry experts studied the app and its success in preventing pregnancies among women from five countries. The results, published online yesterday, further confirmed the 93 percent effectiveness figure.
“The data adds to a growing body of scientific evidence demonstrating the real-world effectiveness of Natural Cycles as a method of birth control for women who are willing to measure their temperature regularly and abstain from unprotected sex on fertile days,” Simon Rowland, M.B.B.S., head of medical affairs for Natural Cycles, said in a statement.
In the study of 54,372 women, the app emerged between 92.5 percent and 94.9 percent effective, according to the findings.
The women, who were between ages 18 and 45 and logged at least 20 data entries, were from the U.S., the United Kingdom, Sweden, Australia and Finland. The study relied on typical use, which considered women who might have had sex on a day when Natural Cycles advised against it, the app incorrectly overlooking a fertile day and whether a physical method of contraception failed.
Researchers used the Pearl index — the number of pregnancies in a group of 100 women over a year — to measure the strength of Natural Cycles. They found that the typical use Pearl index number was 7.5 for Finland; 6.1 for the U.S.; 6.1 for Sweden; 5.8 for the U.K.; and 5.1 for Australia.
Although the data were not far off, the study still armed researchers with an understanding of how Natural Cycles might work for different populations. It also expanded the sample size, as the app gained FDA approval thanks to a study of 22,000 women.
The app allows women to avoid pregnancy by monitoring their resting body temperature — known as the basal body temperature — and recording their data so that an algorithm can determine their daily fertility.
Last month, Healthcare Analytics News™ published a story noting that Natural Cycles does not work for every woman. Those with “very irregular” periods might not find it effective, the company acknowledged, and it has yet to explore how Natural Cycles might work for people with disabilities.
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