For an estimated one in six European couples, trying for a baby proves an often fruitless and frustrating process. Those wanting to avoid invasive techniques like in vitro fertilization (IVF) and opting for a more natural approach may find their lives being taken over by complicated calendar-based calculations or early morning toilet duties. UK-based Cambridge Temperature Concepts has developed a sophisticated body temperature measurement system which helps couples predict the best time to plan for a romantic evening, and is backed by a money-back guarantee. A wireless sensor stuck under the arm continuously monitors the minute changes in basal body temperature indicative of ovulation, and wirelessly sends the results to a hand-held reader which displays a six day optimum conception forecast.

Inventor Dr. Shamus Husheer came up with the idea to create a device that automatically identified the small change in base body temperature associated with that often-elusive fertility window (those days when conception is most likely) while studying for his PhD in Nuclear and Structural Chemistry at Cambridge University. Together with a team of fertility experts and postgraduates, Husheer set about building a prototype to prove the concept and to secure the funding needed for further development.

Lots of refining and testing led to the creation of the DuoFertility system, which consists of a coin-sized sensor which is placed discreetly under the arm with the help of an adhesive patch. The sensor takes 20,000 daily body temperature measurements to within a thousandth of a degree. Temperature measurement is said to offer 99 per cent ovulation time accuracy. The data collected is then wirelessly transmitted to a computer-mouse-sized digital reader where complex algorithmic calculations help predict ovulation up to six days in advance.

Husheer explained that: "having a few days notice to plan for a romantic evening, according to our users' feedback, removes a huge amount of stress and can make a significant improvement to the chances of becoming pregnant." Detailed analysis of the collected data can be performed via transfer to a computer display, where charts showing monthly cycles can be printed out for medical personnel or uploaded to the company's "team of world-class fertility experts" for advice and assistance.

The sensor looks for a subtle rise in the basal body temperature – as little as 0.3 degrees Centigrade – caused by the presence of progesterone, secreted by the corpus luteum (the ruptured sac left behind after the release of the egg). Users can add to the system's accuracy by inputting personal information such as menstruation cycles, cervical position, mucus quality and digital and traditional LH tests.

Cambridge Temperature Concepts Ltd is so confident that its system will be of help that it has backed up DuoFertility with a 12-month money-back guarantee. Its team of "fertility experts" will also be on hand during that time to help users interpret results or identify and advise on any unusual readings.

The DuoFertility system comes with a sensor, reader, adhesive patches, a USB cable and instructions and is available now for GBP495 (US$778).

The short video below demonstrates the system in action: