Assuming that they're not born with a hearing impairment, your baby will be able to hear the soothing lullabies you whisper from day one. As they grow, their hearing will be an important part of their development – even physical milestones such as rolling over, crawling and walking are linked to their hearing.
So how does a baby's hearing develop?
Remarkably, the process begins in the early weeks of pregnancy. In fact, typically, when your baby is no bigger than a pea (week six), the cells in their head have already begun to arrange themselves into unique tissues that will become their brain, face, eyes, nose and ears.
By week nine, small indents that will eventually become ears will appear on your baby's neck. They will gradually move up and grow into the adorable little ears that they are born with.
Your baby's ears will continue to develop throughout the first and second trimester. By week 16 the structure of the inner ear will be established enough for the baby to begin detecting some noise – sounds that you won't even be aware of, such as your heart beat and the gurgle of your stomach.
By week 24 your baby will be more aware of the sounds coming from the outside world. They will begin turning their heads towards voices and noises. Of all the sounds your baby hears, the voice of their mother will be the clearest. This is because, while other voices are being transmitted through the air to the uterus, your voice reverberates through your body, essentially amplifying it. Studies show that the foetal heart rate increases when the mother is speaking, which indicates that the baby is more alert.
You can help your baby get to know your voice by singing, reading out loud or simply talking to your growing bump. When born, they will recognise the sound of your voice.
By the time your baby is a month old, their hearing will be fully developed. But of course, understanding what they are hearing will take much longer!
At three months of age, the part of your baby's brain known as the temporal lobe will have become more active. The temporal lobe assists with language, smell and hearing. You will start to notice that when you talk to your baby he or she will start to respond by gurgling back.
At five months old your baby will be able to recognise their own name and will turn towards you when you say it. You can support your baby's development by exposing them to a range of new sounds – you can play music (you don't need to stick to children's tunes) and introduce musical toys such as rattles.
Hearing issues and checks
While the majority of babies have perfect hearing, a small percentage will have difficulties. Premature babies or babies that were deprived of oxygen at birth are particularly vulnerable to hearing problems. Likewise, if there is a history of hearing impairments in your family, then your little one is more likely to have hearing issues.
So how can you tell if your baby has any issues hearing? In Australia, all newborn babies are offered a hearing test shortly after birth or within their first few weeks. This takes place at the hospital, a community clinic or in some cases the test can be done in your home.
However, as they develop, you can assess your child's hearing using a few quick tests at home. For example, does your three-month-old startle if you clap your hands behind his or her head? Does your six-month-old respond to the sound of their name? Does your 15-month-old follow simple instructions such as pointing to a familiar object? If they do these things then chances are their hearing is fine.
Like any health concerns though, if you suspect that there may be an issue with your child's hearing then you should go and see your GP. There is a lot to be said for parental instinct, and the sooner a problem is detected the easier it is to resolve it.