You’ve been on this new journey for over two months already, and at 9 weeks old we can bet you’re starting to notice all sorts of milestones in your baby’s development. From rattling to baby growth spurts, we’re here to answer all your questions about your 9 week old baby's development.
9-week-old baby sleep
Your baby should be starting to sleep in solid blocks at night, usually about five to six hours. Although, it’s different for each baby and other hours are still completely normal.
However, as their night time sleeps get longer, their daytime naps might be getting shorter. They’ll be sleeping on average between 11 and 15 hours per day, with naps becoming less frequent but longer, giving you more time in the day to get things done or relax.
To relax them before bed, try feeding at about 10pm or just before you go to sleep yourself, as it will induce a sleepiness that should tide them over until they wake in the night for a feed.
You should try establishing a little routine for your baby now too. This can include having a warm bath, reading them a story and feeding them too. This can help them get used to associating night with going to sleep.
Swaddling should still be coming in handy, but your baby’s growth spurt may be taking a toll on the wrap now. You can also use a baby sleeping bag. Also, make sure your baby is not overheating if it’s summer – it’s a good idea to keep a close eye on the temperature in your baby’s room.
9-week-old baby physical development
Your little one will have grown about two inches since being born and probably gained a few pounds.
As they’re gaining weight, they’ll start to fill out a bit, giving them those adorable chubby baby thighs and arms. Those little legs and arms will likely be constantly moving nowadays, always kicking and shaking with excitement. Your baby, week by week, will show more coordination and control over their seemingly jagged movements.
They may now be able to raise their shoulders during tummy time, but don’t worry if their neck muscles aren’t strong enough yet, every baby develops at a different pace and before you know it, they'll be using their arms to support themselves.
• Muscle control: Your baby is taking extra interest in their rattle now, the kicks and punches they learnt at the 8 week baby stage, they will be making all sorts of noise! It’s a great chance for them to develop their ability to identify sounds, their coordination and muscle control. They also want to hear you speak and hear the different tones and pitches in different voices, so keep chatting to your baby and give them a chance to coo in response.
• Grabbing: With your baby noticing more things on people’s faces and sounds around the room, their new interest may lead to over excitement and a lot of grabbing. As they develop their arm and hand muscles, expect to be grasped and grabbed all the time. Now might be the time to avoid those dangly earrings.
• Making new friends: With your baby more alert and sociable during the day, it’s a good week to organise play dates and get out of the house more. As you start to settle into life with a baby, it's good for both of you to visit baby sensory groups to meet other parents and babies. You’ll both be better off for a bit of outside interaction.
9-week-old baby cognitive development milestones
If you're wondering when your baby will start smiling, you'll be pleased to know that they will very soon! Your baby’s understanding of sound will greatly improve this week too, so keep chatting and singing to them, you might get to see that gummy little smile!
You may notice your baby has different reactions now too, so it’s a good idea to play a gentle lullaby for when you want to introduce nap time.
While your baby’s hearing has been fully developed for weeks now, they will start to be more interested in the sounds they hear, which is why their reactions differ so much. Nine weeks is a good time to give them their first rattle as you’ll notice them excitedly trying to work out where the sound comes from, shaking it non-stop!
Another sense your baby is developing is sight. They should show much more interest in different faces this week and into week 10 of baby's development, as their 3D vision develops. You’ll see them staring intently trying to figure you and other family members out. Objects or sounds about eight inches in front of them will catch their attention and they may start turning to identify where a sound or face is in the room. It’s a great time to bond with your baby and watch them smile when they see your face.
9-week-old baby jabs
You should have had your immunisation appointment at 8 weeks, but if you’re only just fitting it in or they had to be postponed, check our baby vaccine calendar for upcoming jabs to be aware of.
During their appointment, they’ll receive their first dose of the 5-in-1 injection against diphtheria, tetanus, whooping cough, polio and Hib (haemophilus influenza type B).
Then, they’ll get their PCV (pneumococcal conjugate vaccine) which fights pneumococcal infections, Rotavirus vaccine (which is a common cause of diarrhoea and sickness) and Meningococcal Group B which protects against things like meningitis and septicaemia.
They will receive these vaccinations either by injection or for rotavirus orally (a liquid dropped into their mouth). The injections are given in their upper thigh, one injection for each leg. It might sound traumatic, but should only take a few seconds.
You may need to postpone the immunisations further if your baby has a fever, diarrhoea or are very unwell, but if they just have a cough or cold they should go ahead just fine. Watch out for the fever they may get from the meningitis B vaccine, your nurse may advise you to give your baby infant paracetamol if a fever does develop.
How much should a 9-week-old baby be eating?
Gaining almost three pounds since birth, they’re sure to be feeding more than when they were a newborn. As they continue to experience different growth spurts, they’ll be feeding more, usually about five to six feeds over 24 hours is normal at this age but just keep following their lead for when they are hungry – they won’t overeat at this age.
One good guideline is to feed them 150-200ml per kilo of their weight, although you won’t be able to measure that if you're breastfeeding and not expressing, so just continue seeing their reaction, and if they seem full after one breast still offer them the second just in case.
If your baby is suffering from colic (defined as uncontrollable crying for more than three hours, three times a week for at least three weeks) they’ll usually settle in a few weeks time.
As they’ve gained weight and height, they’ve been feeding much more and therefore pooing more. However, many babies only poo once per day and some will fill their nappy a lot more frequently – anywhere between one and ten nappies a day is fine. If your baby is going less than three times per week, or seem uncomfortable or in pain when they go, they may be constipated and need to see a doctor. Your baby's poop colour can tell you a lot about the health of their digestive system too.
What problems should parents of a 9-week-old baby be aware of?
• Daytime sleep: Daytime sleep is important for development, but some babies start to struggle to nap at 9 weeks. Baby sleep expert Jo Tantum advises: 'Watch for their tired signs – rubbing eyes and ears, staring into space, getting grumpy, yawning, then take them into their room. Total blackout blinds, sleeping bag and cuddles, try wave sounds to help calm them, too. Try giving them a comforter to hold – I suggest a muslin square knotted in the middle as this helps as their motor reflexes are wanting to grab things so this can really help comfort them.'
• Crying: Even if you haven’t been dealing with colic you might be starting to wonder exactly why your baby is crying. All of this growing takes a toll on your baby, so they may be crying because they are frustrated, plus the usual hunger and sleepy cries that you’re probably used to by now.
• Postnatal Depression: Postnatal Depression can occur at any time in the first year of your baby’s life. With one in ten women suffering with postnatal depression, you’re definitely not alone. It's important to understand the signs and seek help as soon as you can.
About the expert
Jo Tantum encourages confident parenting and gently guides parents to better understand their babies, based on their natural feeding and sleeping patterns. She spent 3 years studying and training for a Community Childcare Course and the NNEB diploma (Nursery Nurse Education Board) within that training she worked in the City Hospital’s paediatric ward, a Baby unit with babies from 6 weeks old and a Nursery for 3-5 years old. Jo was a Maternity Nurse for 10 years travelling around the World looking after Newborn babies including twins. She then was asked to sleep teach several set of twins that weren’t sleeping and this Gentle Sleep Training (teaching) continues now online.
Georgia Aspinall is senior features writer at Grazia UK, formerly at The Debrief. She covers news and features across women's health and fitness, sex and relationships, real-life stories, travel and politics.