Is This Trendy $330 Fertility Thermometer a Ripoff? – Info News

In 1935, German priest Wilhelm Hillebrand encountered an important problem: Many of his church attendees were having unwanted pregnancies. Instead of turning a blind eye to the issue, Hillebrand sought to resolve it. He recalled reading a chapter in a book by Dutch physician Theodoor Hendrik van de Velde — called Ideal Marriage — which was on the Roman Catholic Church’s list of forbidden books, or the Index Librorum Prohibitorum.

Hillebrand’s sharp memory helped him recall that the corpus luteum — structures inside an ovary that secrete progesterone — influence body temperature. So he decided to conduct an experiment. Using a clinical thermometer, Hillebrand monitored the daily temperature cycles of 21 women for six months, between August and December 1935, and found that body temperatures are elevated during ovulation. He went on to produce the first temperature-based method for birth control and was later awarded an honorary doctorate from Albert University of Cologne.

Today, more sophisticated methods of monitoring fertility and preventing unwanted pregnancies exist. In the United States, among all women who use contraceptives, around 3 percent are now using fertility-awareness based methods (FABMs), which consists of tracking ovulation to know what parts of the month women should use extra protection. Recent years have seen a rise in FABMs: One analysis found that only 1.1 percent of American women using contraception used FABMs in 2008 and that numbers have steadily increased since.

The underlying principle of some of these FABMs is based on the forward-thinking work of Hillebrand more than 80 years ago — that is, monitoring changes in temperature after the release of progesterone is a reliable way to predict a woman’s fertile window. Between one and five out of 100 women will get pregnant using this method correctly, according to the American College of Obstetricians and Gynecologists.

The fertility-tracking device Daysy is one of several tools that uses temperature change to make its predictions. To use it, women simply enter whether they have their period and place the device under their tongue in the morning so Daysy can measure their basal body temperature, which increases by 0.25 to 0.45 degrees Celsius around the time of ovulation.

The point of tools like Daysy is to identify the window in each menstrual cycle when the chance of conception is highest. Daysy can also be connected to DaysyView, a smartphone app that stores the user’s personal data. According to the product’s website, Daysy (which is manufactured by Valley Electronics AG in Zurich, Switzerland, and sells for around $330) tells women which days they’re fertile or nonfertile with 99.4 percent accuracy.

That success rate is based on a study — which was funded by Daysy’s manufacturers — published in March 2018 in the journal Reproductive Health. This study was conducted by Martin Koch of University Hospital Erlangen in Germany and colleagues. They contacted 6,278 Daysy users, 13 percent of whom completed their survey. Some of those respondents were also using other methods of contraception, and the authors further filtered out women who reported using the fertility monitor for fewer than 13 cycles. Of the remaining 125 Daysy users, only two reported unintentionally becoming pregnant when using the device, the study found.

A follow-up commentary, however, published in Reproductive Health in June 2018, is calling for the Koch et al. paper to be retracted, citing serious flaws in its methodology. Commentary author Chelsea Polis, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, concluded that the original study “produced unreliable estimates of contraceptive effectiveness for the Daysy device and DaysyView app, which are likely substantially higher than the actual contraceptive effectiveness of the device and app.”

In an interview, Polis told Medium that the manner in which data are collected in the study is “highly problematic.” For instance, she says, it’s questionable whether women would own up to unintended pregnancies in a self-reported retrospective questionnaire. According to Polis, the study also differs from standard practices of reporting contraceptive effectiveness by excluding women who used Daysy for less than a year (or 13 cycles). This approach would “severely underestimate unintended pregnancy rates,” Polis wrote in the commentary, since women who are least experienced in using the contraceptive method may be at a greater risk of unintended pregnancies.

An important distinction between Daysy and other FABMs, Polis notes, is that Daysy uses an algorithm to decide on behalf of the user which days are “fertile and nonfertile,” whereas many other devices let the user interpret the likelihood of fertility.

“My concern is that such unreliable estimates might be interpreted by the public as indicative of the real contraceptive effectiveness of the Daysy device,” Polis says.

Koch, however, says, “We still think that the outcome of the study is strong and can be compared with other studies, especially in the field of fertility awareness methods.” (Koch has not yet responded to any subsequent questions. A Daysy representative referred Medium to Niels van de Roemer, a study co-author who is an employee of Daysy’s parent company. He also has yet to respond to questions.)

Polis praised Reproductive Health for publishing a commentary that’s critical of one of its own previous papers, since scholarly journals often notoriously reject such papers. This appears to be in keeping with the journal’s commitment to greater transparency; unlike most academic publications, Reproductive Health publishes the names and feedback of peer reviewers who refereed its manuscripts — known as “open peer review” in the academic world — on its website.

Richard Fehring, director of the Institute of Natural Family Planning at Marquette University in Milwaukee, Wisconsin, peer-reviewed both the original paper and the commentary. Fehring told Medium he doesn’t think the original study should be retracted, but he did echo similar concerns to Polis about its methodology. Fehring says numbers used by Daysy’s creators for advertising or marketing purposes should be from a prospective study where users are tracked cycle to cycle with robust statistical methods rather than from a retrospective survey.

Daysy’s estimates about which days are fertile and which are nonfertile are based on the algorithms originally created as part of the fertility monitors Lady-Comp and Baby-Comp, created by Valley Electronics GmbH, a sister company of Daysy’s manufacturer. These tools, which are alternatives to the contraceptive pill and the coil, have been on the market for around 30 years.

Günter Freundl, an obstetrician and gynecologist at the University of Düsseldorf in Germany who reviewed the effectiveness of Lady-Comp and Baby-Comp two decades ago, thinks the Koch et al. paper should be retracted. Similarly to Fehring, Freundl advocates a need for statistically powerful prospective analyses. “All other studies are useless,” he says.

Springer Nature, which publishes Reproductive Health, says the journal is looking into concerns raised in the commentary.

Fehring argues that there is no strong evidence that Daysy is any better or faster than just using a digital thermometer to measure temperature manually. Technology is moving past what Daysy does, he notes. For example, devices such as Ava — available as a bracelet that measures many physiological parameters, such as sleep quality, physiological stress, and fertile window — automatically measure body temperature continuously and are connected to apps through Bluetooth. Therefore, Fehring adds, a comparison study looking at how well Daysy works compared to other tools would be a good next step.

For now, Polis thinks that Daysy lacks sufficient evidence for it to be used as a contraceptive device. “We have absolutely no idea how effective it may or may not be,” she says.