Ad Alert

Daysy: The Contraceptive That Isn’t

"They're manipulating people, toying with their understanding of what contraceptive is and isn't."


Ad Alert

Daysy: The Contraceptive That Isn’t

The latest: In May 2019, Reproductive Health retracted the study behind claims that Daysy is 99.4 percent effective at “planning or preventing pregnancy.” In the retraction note, the journal cited concerns “about the reliability of the estimates of contraceptive effectiveness for the Daysy device when being used together with the DaysyView app.” In August 2018, the FDA cleared a controversial fertility awareness method and app called Natural Cycles to prevent pregnancy. Like Daysy, Natural Cycles uses temperature to predict fertility. The FDA said in a press release at the time that clinical studies show that Natural Cycles is about 98 percent effective at preventing pregnancy when used correctly. Our original ad alert follows.

“Are you hoping to transition from the birth control pill to Daysy?” the marketer of the device asked in a February 2018 tweet (that has since been deleted).

On social media, Switzerland-based Valley Electronics markets its $330 Daysy device and attendant DaysyView app as a contraceptive and a hormone-free alternative to using an IUD or the pill. But elsewhere, the company doesn’t seem so sure.

Case in point: After Chelsea Polis, a reproductive health epidemiologist, published a commentary in Reproductive Health in June that challenged the contraceptive effectiveness of Daysy, the company issued a statement that said Daysy is not a contraceptive per se:

… Daysy is not a contraceptive in the real sense. Daysy is a fertility tracker that uses the fertility awareness method (FAM) by tracking and analyzing the individual menstrual cycle.

Fast-forward to today, and over on the product’s website Valley Electronics contends that Daysy is not a contraceptive in any sense — real or make-believe:

Daysy is not a contraceptive. Daysy tells you when you are in your fertile window. During your fertile window, you can choose to use a contraceptive …

Why the mixed messaging?

“They’re manipulating people,” Polis said in an interview, “toying with their understanding of what contraceptive is and isn’t.”

Fertility awareness methods like Daysy use biomarkers (in Daysy’s case, body temperature) to identify fertile days on which to avoid unprotected sex, use protection or conceive. (Daysy lights up red on fertile days, green on infertile days and yellow on days when it’s unsure.) But the effectiveness of these methods in planning for and/or preventing pregnancy is a matter of debate. And sometimes, they don’t work.

Polis’ commentary takes aim at the published analysis behind Valley Electronics’ claims that Daysy is 99.4 percent effective at “planning or preventing pregnancy.” The analysis, which is currently under editorial review following Polis’ request for retraction, looked at survey data from the 13 percent of registered Daysy users who responded to a questionnaire sent out in November 2016. One of the issues that Polis had with the survey itself was how it referred to an unintended pregnancy as an unwanted pregnancy, when an unintended pregnancy can be one that is wanted but mistimed.

But Polis said the analysis ultimately erred when it excluded from its calculations of contraceptive effectiveness women who had been using Daysy for fewer than 13 menstrual cycles. This was a group that not only comprised the vast majority of survey respondents but one that was arguably at greater risk of unintended pregnancy due to the fact that they were new to the method, Polis argues in the commentary.

“Women are believing them because there’s a study,” Polis said. But the study, she asserts in her commentary, is “fatally flawed.”

Niels van de Roemer, medical director for Valley Electronics and a co-author of the Daysy analysis, said in a statement to that the company has “submitted a clarification” to Reproductive Health that addresses the concerns raised by Polis in her commentary.

The journal declined to comment, citing the ongoing review.

Check back for updates.

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