The ability to hear a baby has been formed since he was still in the mother's stomach, which is around the age of 23-27 weeks in the womb. Therefore, it is not surprising that many pregnant women are advised to talk or sing to their babies in the womb. Because the baby can start listening since he is still in the womb, the mother can begin to introduce him to the sound since he was pregnant. This method can be one step so that the baby begins to recognize the mother's voice, as well as a way to strengthen the relationship between mother and baby. Infant Hearing Development Stage The formation of the ear as a hearing organ begins in the 4th to 5th week of pregnancy, along with the formation of the face, brain, nose and eyes. Then at 18 weeks' gestation, then the baby's hearing process begins to function. When entering the second trimester of pregnancy, the baby in the womb begins to hear the sound of the mother's heartbeat, movement of air in the lungs, bowel ...