You may be able to tell if your baby can hear sounds outside your womb (uterus) by playing music, and reading or talking to him. If he can hear what's going on, he may respond by moving around more. .Your baby will start to hear between 23 weeks and 27 weeks. The constant beat of your heart is the clearest sound for him, but he'll also be able to hear some of the things going on around you. Your baby will only hear low-pitched sounds to start with. These sounds will be mostly what's going on in your body, such as blood pumping through your vessels, your tummy gurgling and your breathing. babies get used to the music and voices they've heard in the womb. When your baby is born, if he hears sounds he's heard before birth, he may respond by appearing more alert and active. Your newborn may also pay more attention to your voice than any other.