Baby lying on scales with mother smiling nearby and doctor holding feet

12 Week Old Baby Development

12 weeks old baby

Your baby is officially 3 months old. The first 12 weeks of life can be challenging for new parents and their babies. Getting to know each other and becoming familiar with what works for you both can take a few months of trial and error. If your baby has been wakeful and prone to fits of crying, feel reassured that there are probably easier days ahead. There is generally a steady improvement in unsettledness from now on and babies tend to be a little easier to handle. It’s unlikely though you’ll wake up one morning this week and find they are just less demanding. Change can take a little time.

You will have found what works to soothe and calm your baby, how they like to be held, how often they like to feed and what you can do to entertain them. Although each day will be a little different, there will be more of a pattern or routine to your days and you may even find yourself with moments of time to yourself.

If you feel up to it, perhaps you could arrange for someone to care for the baby while you and your partner have a couple of hours out together. See a movie, have a meal, go out for a coffee or just sit and talk. Make an agreement not to talk solely about the baby though. Willing Grandparents would probably love the opportunity to mind your baby and may have suggested this to you already.

Do what feels right for you and gives you both some peace. Amongst all the other things you need to fit into your life right now, try to remember to include some time with your partner. Even if you don’t actually make it out of the house together, having some couple time is valuable. United, strong  couples see parenting as a shared process and their children can only benefit from this approach.


Many babies go through a growth spurt at this age and want to feed more often for a few days. You could feel as if you are chained to your feeding chair but try to go with the flow. Growth is directly influenced by kilojoule/energy intake and babies don’t always grow steadily and at the same pace. They can literally grow overnight. Children generally grow faster during spring and summer, not unlike plants really.

Your baby still doesn’t need any other nutrition other than their milk. Although well meaning friends and relatives may suggest offering solid foods, nod politely and know, without doubt, that your breastmilk or the formula you are offering is sufficient for them at this stage. Check the formula can for a general feeding guide, but bear in mind your baby’s individual needs may be different from what is stated.

The recommended feeding volume from 5 days to 3 months is 150ml per kg of body weight per day. From 3-6 months it decreases to 120ml per kg of body weight per day.


Keep placing your baby on their back to sleep at 3 months. Very soon your baby will start rolling. This is generally from a back to front direction first and then, after a short time they learn to roll the other way. Supervised floor time every day will help them to practice and perfect their rolling skills. If your baby is still happy to be wrapped, keep doing this. In fact, wrapping will help to stabilise your baby on their back and is a protective strategy against SIDS (Sudden Infant Death Syndrome) particularly at this age and stage.

If you have been happy to cuddle or feed until they are asleep, perhaps you are finding this an issue. Changing one small thing you are doing can often lead to big improvements. Consider placing them into their cots when they are still slightly awake and soothing them whilst they are in there. During the night, babies are often more sleepy and will settle back to sleep relatively easily after being fed.

If you are breastfeeding, you may find that sitting up in your bed and feeding is the most comfortable option, especially in the cold winter months. Just remember not to fall back to sleep with your baby in your bed. Positioning their cot next to your bed will be the safest option for your little one.

If you are bottle feeding, this makes it easier for feeding to be shared between you and your partner. Having the formula pre-made and stored in the fridge will help with overnight feeds.

Behaviour and development

Watch your baby hold a rattle in their hand and wave it around. They are likely to clonk themselves on the head with it though, so make sure it is soft and won’t hurt them. Their grip can seem surprisingly strong and they will be learning to reach and grab objects which interest them. Your baby will be able to kick and extend their legs and may even be trying to put their little feet towards their mouth.

Some babies still show signs that they are refluxing at 12 weeks. The sphincter at the top of a young baby’s stomach can be lax and this allows the contents of their stomach to easily regurgitate up their oesophagus (food pipe). Unless your baby is failing to thrive or they are difficult to manage because of their reflux try not to be concerned. In the majority of babies, reflux improves with time and gut maturity.

If your baby has been prescribed medication to control their reflux, the dose may need adjustment as their weight increases. Some parents find that as their baby matures, they vomit more, not less. This can be related to their increasing mobility and the fact that they are not as stationary as they were.

If you are still concerned speak to your healthcare provider.


Your baby will be more predictable with their crying now and you are probably more adept working out what is wrong. Sometimes it can be hard to tolerate a baby’s crying, especially when they have been at it for a few hours. Be prepared to have some days which are more challenging than others. Ask for help; keep a list of numbers and names by the phone of people you know would be supportive. Let your partner know if you are struggling. The early days of parenting are not necessarily the most challenging.


Your days will still be fairly controlled by your baby’s needs at 12 weeks. Perhaps your little one is sleeping for a longer period overnight and is more wakeful through the day. Avoid the temptation to keep them up during the day and expecting this will encourage them to sleep better overnight. At this age, day sleeps directly influence night sleeps. An overtired baby is a cranky baby so try to follow a routine which suits you all and remember to be flexible.

What you can expect?

If you are breastfeeding, you may have found your baby isn’t having as many dirty nappies. It is common in the first couple of months for babies to poo every time they feed, but this tends to slow down at around this age. Don’t worry if everything else seems to be fine. Breastfed babies rarely become constipated and as long as they are still gaining weight and thriving, these are signs they will be getting sufficient milk. If your baby is formula feeding and their poos are a pasty consistency, this is normal. Khaki or greenish poos are due to the iron contained within the formula.

Your baby can focus more clearly with their eyes now and can track objects when they move together. In the next month or so, their colour vision will mature. This is a stage of rapid changes in your baby’s eyes which need to be protected from bright light. Avoid going out in harsh, direct sunlight if you can. If you are breastfeeding ensure your diet is high in green leafy vegetables, yellow vegetables and a wide range of fruits. These all contain antioxidants and specific nutrients which will help to protect your baby’s retina against light damage.

Do you know that an average baby will need 1057 nappy changes in the first 6 months? Get exclusive promotions and free diaper samples by joining the Huggies Club now! As a member, you can also gain exclusive access to the Huggies Forum and connect with experts to get more personalized pregnancy and parenting advices.

The information published herein is intended and strictly only for informational, educational, purposes and the same shall not be misconstrued as medical advice. If you are worried about your own health, or your child’s well being, seek immediate medical advice. You should never delay seeking medical advice, disregard medical advice, or discontinue medical treatment because of information on this website. Kimberly-Clark and/ or its subsidiaries assumes no liability for the interpretation and/or use of the information contained in this article. Further, while due care and caution has been taken to ensure that the content here is free from mistakes or omissions, Kimberly-Clark and/ or its subsidiaries makes no claims, promises or guarantees about the accuracy, completeness or adequacy of the information here, and to the extent permitted by law, Kimberly-Clark and/ or its subsidiaries do not accept any liability or responsibility for claims, errors or omissions.


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