Smartphone applications for women to track their menstrual cycles fall short, according to a study that analyzed the current available apps for accuracy in tracking women's varying cycles.

Conducted by researchers at the University of Washington (UW), the study looked at 2,000 reviews of apps and surveyed 687 women on why and how they track menstrual cycles. The team found apps erred in assumptions about sexual identity and focused more on appearance than function.

"People didn't feel like the apps were very good at supporting their particular needs or preferences," said lead author Daniel Epstein, a doctoral student at the UW's Paul G. Allen School of Computer Science & Engineering. "People felt they were better than tracking their periods on paper, but still weren't great in a lot of basic ways."

Half of the women surveyed used apps to track their menstrual cycles to prepare for their periods, achieve or avoid pregnancy and be more informed when speaking to their physicians. Other participants used digital calendars, paper diaries and tracking symptoms.

The study focuses on nine of the most popular menstrual tracking apps, asking what characteristics users liked and disliked. Users concluded that the apps were not accurate in tracking menstrual cycles and would not let users input data or customize an app.

"It's a trope at this point that the 'shrink it and pink it' approach to designing technology for women revolves around making something smaller and making it pink and taking all the functionality out of it," said Epstein. "We definitely found that in the menstrual tracking apps, and that was one of the things that users had the biggest negative reaction to: 'Why is my app so pink?'"

Researchers made five suggestions in improving menstrual tracking apps:

1. Allow users to provide customized feedback.
2. Focus on the apps inner workings rather than outward appearance.
3. Be discreet in design.
4. Allow users to export information.
5. Recognize users individual menstrual tracking needs.