A fertility app that tracks the times of month when a woman can and cannot become pregnant has been found to be as, or more effective than artificial methods of contraception for avoiding an unplanned pregnancy. The app was developed as a means of helping women in the developing world to manage their fertility without having to resort to long-acting hormonal contraception or abortion.

Researchers from the Institute for Reproductive Health (IRH) at Georgetown University Medical Center studied women’s use of the Dot app over 13 menstrual cycles, or about one year.

Their study, published in the European Journal of Contraception and Reproductive Healthcare, is the first to test a fertility app using best-practice guidelines for assessing effectiveness of family planning methods.

Using historical cycle data and a woman’s period start dates, Dot’s algorithm predicts pregnancy risk for each day of her menstrual cycle, flagging days of high and low fertility. As the app “learns” about her cycle over time, it personalizes a user’s fertile window – the days of her cycle when pregnancy is likely.

The researchers found that the app had a typical-use failure rate of 5 percent and a perfect-use failure rate of 1 percent, which makes Dot comparable to family planning methods such as the Pill.