The Observer, 18 May 2014

Smartphone technology combined with wearable temperature sensors has given new hope to couples diagnosed with unexplained infertility

Victoria with son Ethan, who was conceived with the help of the DuoFertility system. Photograph: Gary Calton For The Observer/Gary Calton

Victoria with son Ethan, who was conceived with the help of the DuoFertility system. Photograph: Gary Calton For The Observer/Gary Calton

Vicky and Jonathan were 23 when they got married and started trying for a baby, and it hadn't occurred to them that they might have any trouble conceiving. That was in 2007, but after a year, Vicky still wasn't pregnant. "It didn't sit easy, because we were both so young," she says. And after a GP referral and a number of tests, they were none the wiser: "They couldn't find anything wrong with either of us."

Fertility problems are estimated to affect one in seven couples in the UK – about 3.5 million people. About 84% of couples who have regular unprotected sex conceive within a year, but those who don't are diagnosed as infertile. And a quarter of them, like Vicky and Jonathan, are given a diagnosis of unexplained infertility – doctors simply cannot find a reason for it. That diagnosis was a mixed blessing for the couple. On one hand, knowing that there was nothing physically wrong gave them hope that they would one day be able to have children. But some days were darker, Vicky says: "On a bad day, you think 'if they can't find anything, no one can fix it for us either'."

It seems surprising that a process that appears so simple and natural should remain so mysterious in such a large proportion of cases. But new technologies, in the forms of apps and wearable sensors, are now helping couples to better understand the intricate physiological processes that influence their fertility, and so boost their chances of pregnancy. By gathering data from large numbers of women around the clock, these apps are also providing researchers with masses of information from which to look for broader clues and patterns about lifestyle and health factors that affect fertility more broadly, which could help other couples too – not just those using the apps. "We get amazing insights into fertility," says Paris Wallace, chief executive and founder of Ovuline, a company that has produced one such app, called Ovia Fertility.

For many women, the science of conception is already a refined one. Taking their basal body temperature measurements first thing in the morning or using over-the-counter ovulation kits are probably the best ways to determine when they are ovulating, and therefore the times when conception is most likely to happen.

Apps such as Ovuline's Ovia or Glow, another popular alternative, help refine this process by allowing women to input such daily information as temperature readings, when their periods occur, what their emotions and moods are, and to track sexual activity and even sexual positions. But Dr Allan Pacey, a fertility expert at the University of Sheffield, is not convinced that these apps are better than traditional methods. "Women have charted their menstrual cycles in a diary or put notes in a calendar for years," he says. "Apps that allow you to input that are just an electronic diary. If you want to use an iPhone rather than a pen and paper that's fine. The question is, how much will it help?"

Wallace says the apps teach users how to take control over their fertility. "For example, many people don't know when ovulation happens or that a couple can only conceive during six days of a cycle until they start using [it]." The manufacturers of the apps claim to use this information to give users tips on how to get pregnant faster. For instance, Glow will calculate the probability of a woman getting pregnant on any one day, and send reminders to her phone to tell her when she's most fertile.

Many of the users – 20% in the case of Ovuline – are infertile, and have turned to the app as an alternative to IVF and other assisted reproductive technologies, or an addition to them. Wallace says there is evidence to show it helps. "The average couple takes four to six months to conceive, but our users do it in 60 days, which is two to three times faster than the national average."

Of course, the same principles can also be used to avoid pregnancy. Apps such as Kindara and OvuView promote their use as a means of natural contraception as well as a way to help pregnancies happen.

One user, who wishes to remains anonymous, says: "I think these apps are really good for people who can't have sex regularly for whatever reason, or who don't really understand their cycle due to not understanding the science or not having regular periods. But if you are capable of having sex two to three times a week, then they're not much use except for peace of mind – seeing you've ovulated [because of] a temperature change, for example."

Where the technology becomes arguably more interesting is that these apps are increasingly becoming compatible with others such as food diaries and activity trackers, allowing data to be used to look for other possible factors in conception. These aren't things that doctors can glean from talking to individual patients. But with hundreds of thousands of people inputting data, it's a different matter.

"At Ovuline, we're undergoing the largest research study in reproductive health in the world," says Wallace. "Our users have submitted over 100m data points about their health and lifestyles, and we're getting 24,000 new data points every hour." Working with scientists at Harvard University, the company is undertaking two research projects – one on the signs of early pregnancy, for instance how your emotions can indicate whether you are pregnant, and the other on a method of "scoring" a person's fertility.

There is clearly a huge market for this kind of technology. Ovuline claims to have hundreds of thousands of users (although it will not reveal exact figures) and says the number is growing by 20% each month. But although these apps are supposed to make fertility cycles easier to track and analyse, for some people, manually inputting the information doesn't work. Vicky, who is herself a midwife, gave up taking her basal body temperature to track ovulation after two months. The temperature has to be taken at the same time every day, and with her shift work it was too difficult. And taking daily readings was adding to the pressure she already felt. The infertility issue "was ruining my life enough without trying to take my temperature every day and do all those things," she says.

After they had been trying for a year and were therefore told they were infertile, Vicky and Jonathan decided to try IVF, but swore that they would only try as many times as they could on the NHS, to avoid getting into debt. With the news that the second round of IVF had not worked, the couple went back to "normal life".

By 2012, they were just beginning to get their heads around the idea that they might never become parents. "We were starting to accept it as much as you can. We started to look at expensive holidays and treating ourselves because we had put our life on hold to try for a baby," Vicky says.