Month by month baby development

You can observe your baby’s development across several key areas. From birth you can follow the progress of movement, the senses and thinking, along with changes in social, emotional and communication skills. Parents are also keen to track their child’s weight and length gains.

In this article we briefly touch on these areas across the main developmental stages. If your child was born early, use corrected age to judge the best pace for their development.

Let’s look at the stages.

Baby development in the first month 

The first month is mainly about adapting to a new environment. Several reflexes help your baby. Limbs are still flexed, though your baby can stretch them out. Movements are not yet separate by body part, arms and legs often work together. Your baby can turn their head to both sides.

They watch light, notice sounds and facial expressions. They learn through an inborn imitation method which is not yet voluntary. Crying is the main form of communication. You can recall the safe feeling of the womb by holding your baby often and talking to them. Babies need to feel secure, and close physical contact is vital for healthy emotional development. From this base of safety they will slowly begin to look outward with curiosity.

Newborns easily recognise mum’s voice, and later can distinguish other familiar voices. Vision is not yet sharp, and the ability to tell colours and details apart develops next.

1 to 2 months 

In this period your baby sleeps a lot, and when awake they wriggle in response to the outside world. They can lift the head briefly. They often react with the whole body to stimuli and the fingers are still flexed. With the grasp reflex they can hold objects that touch the palm.

Even in the womb, touch, body and balance senses work well, so stroking, cuddling and rocking are very important, and are also a channel of communication with parents. Very soon your baby will respond with sounds.

At the end of month 2 you may see the first social smile. This is no longer simple imitation but a smile directed at the parent. Your baby feels the joy of being together.

Shiny, moving objects are attractive, and human voices in particular.

2 to 4 months 

After two months, movements become more intentional, and babies begin to discover their hands. Symmetrical movement is typical and muscles strengthen. By 4 months babies prop on the forearms when on the tummy. Hand–eye coordination progresses and your baby reaches for toys on purpose.

Your baby listens to their own voice more and begins to choose which sounds to attend to. By the end of month 4 the eyes usually move in a parallel way. It matters to place objects nearby so your baby can look, turn towards them and grasp them.

Cooing continues and your baby tries every sound. They imitate adults and themselves, respond and smile back, and use sounds to attract attention.

4 to 6 months 

Primitive reflexes such as grasping, rooting and stepping fade. A new favourite appears, holding the feet and even putting them in the mouth. On the tummy your baby props steadily, and soon with straight elbows. Around 4 months they roll from back to side, and by 6 months from tummy to back, and back again.

They begin to learn object permanence. Things do not cease to exist when out of sight. They work out what they can do with objects and transfer them from hand to hand.

When listening to speech, babies recognise intonation patterns. By six months they mostly use the sound patterns of their native language, and babbling emerges, now with sound combinations, not just single sounds. It is important to hear multiple human voices and tell them apart.

Babies form a relationship with parents through shared attention. They look at the same object, respond and even guide with signals.

6 to 9 months 

This exciting stage brings more deliberate movement, lots of experience and the first signs of independence. Babies sit up, or get into a semi sitting position, and rise onto all fours. Stable sitting is a major milestone because both hands are now free. They commando crawl and crawl. Motivation grows. They pinch toys with the fingers. They notice distance, depth and detail. They enjoy making noises and recognise their name among other sounds.
They begin to imitate simple adult movements.

Babbling becomes more deliberate, with sequences such as papapa and tötötö. Playing together is especially important now as babies increasingly self regulate.

Around six months it also matters to learn chewing and biting alongside the suck, and to practise spoon feeding and drinking from a cup. Babies recognise and look forward to mealtimes.

9 to 12 months 

Movement takes off. Babies commando crawl, crawl, work on getting upright, and by the end of this stage they pull to stand. They often kneel first, then stand, shifting weight from one leg to the other. From here they begin to cruise sideways. They play with more than one toy and try to relate objects, for example tapping them together. Grasping is confident.

Standing gives a new view of the world. Babies move boldly and watch details.

They enjoy throwing, unpacking and searching for objects. Emotions are expressed more clearly in facial expressions and gestures. Stranger anxiety appears. Separating from and returning to parents can also feel uncertain.

They coin proto words which are not yet meaningful but may be used often. They understand simple questions and respond.

12 to 18 months 

Independent walking is preceded by standing unaided, a balance exercise usually between two stable people, objects or pieces of furniture. In walking, babies need to learn to start, turn, stop and avoid obstacles.

They take items off shelves, get to know objects and what they are for. They stack, and put smaller objects into larger hollow ones, learning about size and shape. It is delightful when they spot a tiny speck on the carpet or recognise familiar objects in photos.

Babbling shifts towards recognisable words and vocabulary grows. Emotions show during play, for example by hugging a teddy. Babies can now identify body parts.

They enjoy music and hum, so it is important to make room for singing and nursery rhymes together.

Independence is in the foreground. Nappy changing can be a struggle because lying still is unpopular. Babies like to use a spoon themselves, though this is not yet efficient enough for a full meal, so parental top up is needed.

Swinging is a favourite and highly developmental too. Babies love watching movement and busy scenes. Speech may be jargon with a few real words. Model clear speech, which children learn from.

Baby weight gain 

One of the most useful checks at home is to weigh your baby regularly, weekly at first, then fortnightly and monthly. After birth you may notice physiological weight loss, a normal drop of about 100 to 150 g, which is usually regained within 10 to 15 days. It relates to postnatal adaptation and initially low milk intake.

General values 

• At 1 month, weight gain from birth is 800 to 1000 g, averaging 150 to 200 g per week

• At 3 months: 5100 to 7900 g

• At 6 months: 6300 to 9800 g

• At 12 months: 7800 to 11800 g

• At 2 years: 10.3 to 15.3 kg, with average weights for girls and boys beginning to diverge

Growth varies by child and universal values are not possible. Watch for stand out signs such as no gain within two weeks or weight loss. In such cases, consult a doctor.

Baby length growth 

Newborn length is typically around 50 to 51 cm. In infancy, your health visitor or GP will record larger growth steps. Length growth is influenced by genetics and by adverse factors in pregnancy that affect fetal growth, such as smoking, alcohol use and placental insufficiency. Focus mainly on the rate of growth so you can spot if it is off track.

Babies grow an average of 2 cm per month in the first 3 months and reach around 75 cm on average by 12 months.

Developmental data and milestones vary between individuals, yet it helps to use them as a guide so you can spot unusual patterns sooner and seek specialist advice in time.

Sources:

NHS — Your baby’s height and weight

RCPCH — Growth charts: information for parents and carers