I give this 4 stars cause it is simple and works well for self-timing because of the basic nature.
A couple of suggestions (the app works well regardless of these suggestions! I am using it currently for labor, and am just offering some additional feedback)
1) making the start screen the whole screen, like the stop screen. During contractions, its difficult to focus, or I am in the zone and dont want to look at a screen while breathing
2) red is a very harsh colour to look at during a contraction, since one is supposed to try and relax during them. As a general rule, red tends to have the opposite affect on a persons psyche. Perhaps a pastel colour to be more soothing?
3) the slide bar for intensity is kind of jerky and requires unnecessary time to get the right category. Perhaps just highlighting a word, or a smooth spectrum-of-pain type of bar would be more appropriate.
PCMagReview about Contraction Timer - Time labor, v1.1.4