Contraction Timer, developed by Karl Rosenbaum, is a free Android app categorized under Lifestyle and Health & Fitness subcategory. It is designed to help pregnant women keep track of their contractions during labor. The app lists the start time, duration of contractions, and the interval between them. It allows users to easily predict when the next contraction will start, how long it will last, and when the current rest period is about to end.

The app features an easy-to-use, one-button interface that allows unlimited undo. It shows averages over as many contractions as the user wants and allows them to send stats via email for viewing or processing elsewhere. The timings, including the current one, survive restarts and crashes. Users can choose to keep the display on and can switch between a simple history view that only displays averages and a detailed history view. The app also features a progress bar that gives visual feedback on when to expect the next rest or contraction, as well as sound and/or vibrate feedback on button press. Contraction Timer supports English, Swedish, and French languages.

Overall, Contraction Timer is an excellent app that every pregnant woman should have. It is easy to use, highly functional, and provides accurate information about contractions during labor.