Can Babies Hear Sounds While They are in the Womb?

Once pregnant women get used to the idea of a baby growing inside of them, it is normal that they start talking to the baby, singing lullabies and encouraging spouses to chat with the baby in the belly. These are not just activities that are seen in the movies, studies have suggested that at the beginning of the second trimester of pregnancy, the baby inside the belly can detect sounds from its surroundings. The tunes, noises, and voices that the baby hears do help the get him or her to get used to the environment that they will enter at birth.

It is around the 6th week of pregnancy, even though the embryo is smaller than a pea, the cells inside the baby's developing head are already starting to arrange themselves into unique tissues that will eventually be their eyes, ears, nose, brain, and face. By the 9th week, small indents will start to appear on the side of the baby's neck, even though they are not in their final place yet, they will eventually move up and become small, curled up ears.

Throughout the first and second trimester, a baby's ears continue to grow and develop: the baby's inner ear connects with the neurons in their brain that is responsible for processing different sounds, and the minuscule bones of their middle ear forms, it is the part that can sense the vibration of sound waves.

Around the 16th week of pregnancy, the structures of their ears are likely well developed enough for them to start detecting limited noises. Some of the sounds that they here are sounds that you may not even notice yourself, like the gurgle of your stomach and the air that comes in and out of your lungs. Over the next few weeks, the baby will hear more of the sounds from the outside world, and by week 24, the baby can turn their heads in response to noises and voices.

If you are wondering what it sounds like inside a woman's belly, you can imagine what it sounds like when you are underwater; the sounds do not travel as well as it is when you are in an open space. The same thing goes for the baby; there is amniotic fluid that is surrounding them, plus all the layers of the mother's body and their amniotic sac that is between the baby and the outside world. So when their ears are fully developed, the sounds that they hear inside the belly are muffled.

It is also important to note that when a woman is pregnant, their voice is the clearest noise that the baby can hear. While most sound is transmitted through air, and then through the uterus, when a mother speaks, the sound of her voice reverberates through their bones and the rest of their body, amplifying it.

Studies have shown that a baby's heart rate increases when they hear their mother's voice, suggesting that the baby becomes more alert when their mother speaks. So reading out loud and talking or singing songs to the baby throughout the pregnancy will help them get to know your voice.