Baby Hearing Development

BABY HEARING DEVELOPMENT

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An unborn baby’s hearing develops rapidly in the womb and still has a lot more developing to do after birth, too. Babies won’t hear as well as adults until they are 10 years old, they’re also more at risk of hearing damage and permanent hearing loss and they grow up. In this article, we explain how development progresses, what kind of sounds they can hear (and react to) and offer guidance on how important it is to communicate with your baby in utero and beyond and how crucial a parent’s role is to protect their delicate ears.

Antenatal – 18 weeks

When can a fetus hear for the first time?

At around 18 weeks of pregnancy when the fetus is roughly the size of a green pepper their ears and ear canal will have opened up and developed enough to hear some noises. The unborn baby’s hearing will begin at the most basic level and they are still surrounded by the fluids of the amniotic sac and then, of course, the muscle, fat and skin of the mother.

This means the only noises it will likely hear is the mother’s heartbeat, the sounds of the surrounding fluid and perhaps the noises the umbilical cord. The fetus won’t interact with the noise at this point but it’s interesting to realise just how early fetal hearing starts.

Antenatal – 24 weeks

6 weeks is a long time for a fetus and more work has happened to their hearing capabilities, too. Although at this stage the unborn baby may start to react to the noises of your body but not quite yet to external noises like talking or music. However, it may start to feel the vibrations of noises rather than the sound itself. It may be able to hear the bass from music or the vibrations of the mother as she speaks. Lastly, the fetus will be able to hear your breathing and heartbeat much better than it did at 18 weeks – a noise it will be comforted by and attune to and one of the many reasons womb noises are such a great sleep aid once they’re born as it reminds them of their happy place.

Antenatal – 26 weeks

External noises are muffled by around half due to the fluids and the absence of air, but by the end of the second trimester to the beginning of the third-trimester fetus’ have been found to react to external noises – this might be a kick or just a bit of a wiggle. The most common noise it will react to is the voice of the mother and really loud noises strong enough to get through all that fluid. Studies have also shown that the baby’s heart rate can increase when they hear a noise which means they are alert; it could also be assumed that they are listening!

Is it a good idea to play music to the bump?

There’s no link between playing music to a fetus in the womb and a baby’s love of music after they’re born, there’s also no confirmed link between playing classical music and a higher IQ later in life. There is, however, a link between loud sounds in utero and hearing loss later in life so it’s really not advised to do this. Nobody wants to have a baby with hearing problems so it’s important not to expose a pregnant mother to loud noises even for short periods.

However, what is most certainly advised is to talk to your bump as much possible as your baby will remember the sound of voices and know that they are familiar and friendly when they’re born. No shouting, though!

It’s a really pleasant bonding experience to have conversations with your bump when you’re alone and as long as you don’t shout then it won’t cause any harm.

Postnatal – 1 day

Naturally, babies are born with the ability to hear sounds because they could in the womb. However, their hearing abilities are juvenile and not comparable to an adult’s hearing. Immediately after birth, their hearing canal can be filled with liquid from the amniotic sac which can muffle a lot of sounds on top to their developing hearing, but they can hear. Newborn babies without hearing problems will react to the sound of the mother, high pitched and exaggerated noises (baby speech) and of course very loud noises. It’s important to try and get them to respond to noises to ensure your baby’s hearing is fine. However, depending on the healthcare you are provided they should offer hearing screening services to check if your newborn hearing is OK.

Newborn Baby Hearing Screening

If your baby was born with the help of the NHS then you will be offered medical advice in the form of hearing screening not long after birth, usually before being discharged if it’s a hospital birth and no longer than 5 weeks. This is an optional test but one you should definitely take just be sure that your baby’s ears are working as they should. In the event that there is a health issue, early intervention can make all the difference to avoid permanent hearing damage. 1 in 100 babies is born with permanent hearing loss in one or both ears so it’s worth checking out for family members.

There are two types of newborn hearing screening tests – otoacoustic emission and automated auditory brainstem response. Both work in more or less the same way by making a series of clicking noises in their ears and waiting for acoustic feedback. They are rather rudimentary and basic but in general, can pick up the most common signs of permanent hearing loss. However, straight after birth, they can be unreliable due to the fluids still in the head of the baby giving false negatives and if they fidget and move around this can make it tricky to get an accurate reading, especially for the automated auditory brainstem test which can take up to 5 minutes to complete.

However, you will get the results as soon as the test has been finished.

How to find out if your baby has hearing problems?

A newborn screening test is the best way to find out if your baby has hearing problems but there are also other signs you can look out for yourself – the most obvious is to see if they react to loud noises and voices. If they never seem to react to loud noises by jumping or being startled to them to see a child doctor (paediatrician) as soon as possible. Your midwife can also be of help here for the next steps.

Postnatal – 3 months

By three months of age, a baby will have developed enough to recognise both parents voices when not looking at them. It’s also the age where games like peek a boo can be played with enjoyment. It’s also possible they will be able to recognise the noise of their favourite toys that make sounds such as rattles and the like. People who are often in their lives can also be recognised which is a delight for family and friends which can deepen their bond.

Postnatal – 6 months

By 6 months of age, baby’s ears and hearing have developed enough to detect the direction of sounds and you may see them turn their heads and bodies towards them. This is a sign of good hearing health. It is another milestone which can help you find out if your 4 to 6 months old baby has potential hearing problems and an opportunity to find more information to help them. Newborn hearing screening doesn’t always pick on everything so it’s important for parents to keep an eye out for these sorts of things. Baby hearing development doesn’t stop once they’re born.

Postnatal – 12 months

At 12 months of age, newborn hearing development is still ongoing but at this point, they can start to make noises of their own through babbling and attempting to imitate words. They may be able to say a couple of familiar words such as mama and bye-bye. But, their hearing is still in its infancy and won’t possess adult equivalent hearing until they’re around 10 years of age. If your child seems to be behind with their speech it could be a symptom of hearing loss, not just a speech impediment.

Toddler

Toddlers can hear a wide range of noises and start to comprehend and repeat languages. However, they still can’t hear the full range of sound frequencies an adult can which can be noticed with sounds coming from a distance or particularly quiet noises. Thank god, because having juvenile hearing makes moving around when they’re asleep much easier!

But, their hearing is still much more delicate than adults and should not be exposed to loud noises of any kind – this applies not just to fireworks displays, kids parties but too loud televisions, smartphones and tablets, too. Consider investing in kids ear defends to be able to enjoy some of these things safely.

Pre-school

Up until the age of 10, you wouldn’t notice that pre-school infants can’t hear with the same depth and range as adults but it’s true. Their hearing frequency range isn’t as broad and may miss out some sounds at the lower and higher end of the spectrum. Until they’re 10 an infant won’t have the same hearing sensitivity as adults which may be noticeable in noises in the distance. However, by this age, it will be obvious if they have hearing issues and as long as you haven’t noticed them miss anything obvious there’s nothing to worry about. But, it is still vitally important to help them protect their hearing from damage by limiting their exposure to loud noises, even when they’re in short bursts.

Summary

A child’s hearing develops rapidly in utero and perhaps more slowly once they’re born. But, it never stops improving until they’re around 10 when they have comparable hearing to an adult. What is clear throughout, however, is to ensure they regularly have hearing tests every year and to help them protect their hearing from damage by limiting them from exposure to loud noises. They are more susceptible to permanent hearing damage than adults as their ears themselves are underdeveloped and they simply don’t understand the dangers of loud noises.

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