If you think that your unborn baby responds when you talk to him, you're right. Babies recognize familiar voices even before they're born, especially Mom's voice. After your baby is born, he'll turn his head toward you when you talk, recognizing your voice. You can facilitate his getting to know you by talking to him often even before he enters this world.
Ears take time to develop during pregnancy. The inner and middle portions of the ear, essential for hearing, develop in the fifth month of pregnancy, according to Penn Medicine. By 25 to 29 weeks of pregnancy, your baby can hear sounds from the outside world and respond consistently to them, the American Academy of Audiology explains.
Your baby hears your voice best partially because he's closest to you physically. He hears your voice not only as ambient sound but also experiences it internally through the vibration of your vocal cords. In a Canadian study published in the May 2003 issue of "Psychological Science," fetal heart rate increased in response to a fetus's own mother's voice and decreased when the fetus heard another mother's voice. This effect appears to increase as your due date comes closer, found another Canadian study published in the March 2011 issue of "Developmental Science." In this study, 46 percent of fetuses responded to their mother's voice at 32 to 34 weeks, increasing to 83 percent at term.
Because it's noisy inside the womb and because outside sounds aren't heard as well as internal sounds, there's no proof that babies recognize Dad's voice at birth. Few studies have tested a baby's preference for their own father's voice over other male voices. A 1999 Virginia Tech study published in "Developmental Psychobiology" found that 4-month-old infants did not show a preference for their father's voice over other male voices but did recognize voices they'd heard previously. Researchers concluded that there is a biological difference in maternal vs. paternal recognition in infants.
Talking to Your Baby
Talking to your baby often in a low, calm voice helps him recognize who you are before birth. Your baby learns to recognize and show a preference for the speech patterns and vowel sounds associated with your native language by the time he's born, according to a Canadian study published in the March 2010 issue of "Psychological Science." Your baby may even recognize stories you read to him during pregnancy after birth, suggests a study conducted by Anthony DeCasper at the University of South Carolina.