No contraceptive is perfect, but can you trust apps to stop pregnancy?

WOULD you trust your smartphone to stop you getting pregnant? That might sound ridiculous, but the US Food and Drug Administration has just approved an app called Natural Cycles as a form of contraception. This follows similar approval by the European Union last year, which saw the app garner an enthusiastic following of women eager to stop taking hormonal contraception, but also mounting controversy.

It seems simple. You measure your temperature and tap it into the app, and its algorithm tells you if there is a risk of conceiving that day. Avoid sex or use a condom on those “red days” and you shouldn’t get pregnant.

Of course, things are more complicated than that. The first signs of this were the abortions. In January, it was reported that Stockholm South General Hospital in Sweden had identified 37 unwanted pregnancies among women using the app. These accounted for 5.5 per cent of those seeking abortions there in the last four months of 2017. This prompted the Swedish Medical Products Agency to open an investigation into the app.

Now its adverts are under fire. The UK Advertising Standards Authority announced last month that it is investigating the marketing by the Swedish firm behind the app after receiving three complaints about paid posts on Facebook. The complainants took issue with the app being described as a “clinically-tested alternative to birth control methods”.

News headlines and regretful testimonials seem unlikely to deter other tech firms from following Natural Cycles into the contraception business. In May, Ava – a firm that makes a fertility-tracking bracelet and app – announced it had raised $30 million to expand into various aspects of female health. One of these is preventing pregnancy and the firm is in discussions with EU and US health agencies.

“There is so much confusion about the risks and effectiveness of contraceptive methods”

It is easy to see the appeal of high-tech solutions. Many people only consider two kinds of contraceptive: the combined pill, which isn’t a good fit for everyone due to hormone problems, and condoms, which are unpopular and relatively unreliable.

In reality, more than 10 types of contraception are available along with the combined pill and more permanent measures, like sterilisation (see “graph”). True, condoms, caps, diaphragms and the copper coil (IUD) are the only non-permanent methods besides natural family planning that don’t involve hormones. But many common perceptions about hormonal contraception are myths.

For example, some methods, like the combined pill, are unsuitable for women who are over 35 and smoke, because oestrogen raises their risk of dangerous blood clots, while contraceptive implants, coils and progestogen-only pills are all safe for women with these risk factors.

But there are other reasons why many prefer not to use hormones: reported side effects across various methods include breast pain, headaches and changes in libido (see “Why the Natural Cycles app works for me”).

“There’s no question that [hormones] increase some side effects, and some women are much more susceptible than others,” says Maureen Cronin, chief medical officer at Ava. “There are definitely hormone-sensitive women, and those women can suffer a lot under the birth control pill.”

“I think a big unmet need among women is effective non-hormonal, non-invasive contraception,” says Raoul Scherwitzl, who co-founded Natural Cycles with his wife. “This seems to be especially the case for couples looking to have children in a couple of years but not quite yet. They want to discontinue hormonal contraception and they want to have something that bridges this time.”

Sexual education

This may be a poorly served market, but the demand seems based on people misunderstanding the evidence on contraception.

There is no reason to worry about taking hormones for too long, says Diana Mansour, a doctor and expert in reproductive healthcare in Newcastle, UK, other than for cervical cancer on the combined pill. Hormonal methods don’t hamper future fertility either – there is no need to come off them years before you want to start trying for a baby.

At the same time, there seems to be a lack of understanding about how effective different methods of contraception are, and how this is assessed. The only way to guarantee not getting pregnant is to abstain from sex – even female sterilisation has a tiny chance of failure – so it is no surprise that some Natural Cycles users are finding the app fails.

Last year, a peer-reviewed study by Natural Cycles of more than 22,000 of its users – most of whom were Swedish – calculated that, when used perfectly over a year, one woman in 100 will get pregnant. However, the typical effectiveness is lower, with nearly seven in 100 women getting pregnant (Contraception, doi.org/gck4ht).

These rates may sound high, but they are comparable with the combined pill. If used perfectly, fewer than one in 100 women on it will get pregnant in a year, but under typical use, about nine will. Out of 100 couples who use condoms perfectly, two would be expected to get pregnant in a year, but this rises to 18 among typical users.

Condoms slip down the rankings because many people often skip using them. In some respects, Natural Cycles seems to work best as an app to tell condom users when they really do need to take precautions.

“Natural Cycles basically reduces the number of days where you need to use a condom and informs users on particular days when not using a condom will risk pregnancy,” says Scherwitzl. This leads to better condom use, he says.

Nevertheless, the most common reason why women using the app fall pregnant is still failing to use protection on a red day, he says. In other words, Natural Cycles may only work well for certain types of women: those with regular routines and a disciplined personality who rigidly adhere to rules.

“The women who use apps like this may be quite different from women who don’t,” says Mansour. “I’d be useless at it because I’d never be able to remember to take my temperature every day or input it into an app on a daily basis either.”

Furthermore, Natural Cycles’s study only looked at women who had chosen to use the app, meaning there is a selection bias, says Cronin. Another issue is that many women stopped using the app during the study period. “You can’t just say OK, they’re gone and therefore we don’t count them,” she says.

Of the 22,785 women analysed in the study, only 6944 used the app for at least a full year. Of all the data collected, less than 10 per cent qualified as “perfect use”. A recent comment piece in BMJ Sexual & Reproductive Health criticised the firm’s marketing for failing to mention that few women use the app perfectly.

“I would say that this is really a method for disciplined couples,” says Cronin. But she does believe that contraception apps have a role to play for the many women who are afraid of hormone pills or simply don’t want to take them.

Cronin sees contraception apps as a trade-off: probably not as effective as the pill for the average woman, but better for some women than using condoms all the time. “It’s what women are asking for,” she says.

The difficulty is whether that can be communicated clearly, when there is already so much confusion about contraceptive methods that have been in use for decades. According to Natural Cycles, the unwanted Stockholm pregnancies are in line with what you would expect from its app.

Scherwitzl says the outcry about these highlights a broader knowledge gap in society about contraception and how it works: “In some sense, I’m glad we’re having this discussion now.”

This article appeared in print under the headline “Digital family planning”

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