I downloaded it but I'm only 14wks+3 so didn't expect to hear anything yet(says not until from 30wks) but thought it would be fun to use. It works on my heart and tried it on other friend's bumps who are much further on than me so it definitely works. I put my iPhone in airplane mode so it was safe to use. I also tried it near the hair line on myself and could swear I heard very faint sounds like a chugging train, if that makes sense. Could be me just wanting to hear a heartbeat though :) anyone else used it?