Premature baby development: the basics

A premature baby’s development typically follows the same sequence as it would in the womb.

Your premature baby’s genes are programmed to make development happen in a particular way, and this keeps going even if your baby is born early. But your premature baby might have some health problems along the way. Sometimes babies also have delays in growth and development, especially if they’ve been ill.

All babies are different, and their behaviour and development are different too. With premature babies, the differences also have a bit to do with when they were born.

For example, a premature baby born at 32 weeks is likely to act differently from a baby born at 26 weeks, who has had many medical challenges by the time she gets to 32 weeks. The baby born at 26 weeks might take extra time to put on weight, learn to feed and come out into the social world.

Here are the changes you can expect and watch in your premature baby during his time in hospital.

26 weeks

At 26 weeks, a baby in the womb is about 35 cm long and weighs about 760 gm. But premature babies are often small for their age. A baby born at 26 weeks would probably fit snugly into her father’s hand.

At this age your premature baby’s main job is to grow, sleep and become medically stable.

Your baby might open his eyes occasionally, but he can’t focus. Light or other visual stimuli might stress his body’s systems. Your baby’s nurse will normally cover your baby’s incubator, and some neonatal intensive care units (NICUs) dim the lights at night.

Your baby’s movements are often jerks, twitches or startles. She doesn’t yet have good muscle tone and can’t curl up. Hospital staff will put your baby in a curled-up position, support her body with bedding and keep her warm. This helps her to keep up her energy.

Your baby might also have apnoea. This is common for very premature babies. The breath triggering part of your baby’s brain hasn’t fully developed yet, so pauses between breaths are common. Your baby will grow out of it.

Your baby’s ears and hearing structures are already fully formed, but he might be sensitive to external sounds. Your baby might notice your voice but he can’t yet respond to you yet.

Your baby won’t be able to feed from your breast yet.

Your baby’s skin is fragile and sensitive, and she might get stressed if she’s handled or touched. The nurses will probably encourage you to ‘comfort hold’ your baby, but not stroke her.

Our article on touching, holding and massaging your baby has more information on comfort holding and kangaroo care. And our article on premature baby body language explains what your premature baby’s behaviour is telling you.

26-28 weeks

At 26-28 weeks, babies in the womb continue to put on weight and grow longer. But if your premature baby is sick, his weight gain might not keep up with a baby in the womb. Also, hospitals use careful, staged feeding plans to protect your baby’s immature gut from infection, and this might slow weight gain.

At this age, babies start blinking. They also grow eyelashes and eyebrows.

Your premature baby still has low muscle tone and is likely to have twitches and tremors.

Your baby’s sleep and wake cycles aren’t clear yet, but she might have active and quiet periods and very brief alert times. Your baby might open her eyes, but she probably still can’t focus or get her eyes moving together.

At this age, your baby’s responses to sound might change from hour to hour or day to day. Or he might respond to your voice but get stressed by other noises. His responses will start to give you some clues to what he likes and dislikes.

Your baby might begin sucking, but she still can’t feed from your breast. To breastfeed, she needs to know how to suck, swallow and breathe in the right order.

Your baby’s skin is still fragile and sensitive. But if your baby is medically stable, you might be able to start skin-to-skin contact by doing kangaroo care.

28-30 weeks

In the womb a baby keeps getting heavier and longer, starts to move more often, knows the difference between some sounds – for example, voices and music – starts to grasp with his hands, and opens and shuts his eyes.

At this age, your premature baby will still be well supported with bedding and positioning, but she might move and stretch more actively as her muscle tone gets better.

Your baby’s quiet deep sleep (when he doesn’t move) and light sleep (when he moves limbs and eyes) increase at about 30 weeks. You’ll also start to see short alert and eye-opening periods, but this can be affected by your baby’s health, the environment or the time of day.

Your baby is starting to close her eyelids tightly if it’s bright, but she still can’t move her eyes together very much. Her eyes wouldn’t normally get much stimulation at this age, so it might help to limit what she sees.

Your baby keeps responding to pleasant sounds and is still sensitive to other sounds. He might be quiet and attentive to your voice and might even seem to ‘wake up’ when you come in. You can start to talk or sing to your baby during his short alert times. But keep stimulation to one thing at a time – for example, eye contact or talking, but not both at once.

Your baby’s rooting reflex – turning to a touch on the cheek – might start around this time. This means she’s getting ready for breastfeeding. She might even start sucking, but she can’t feed at your breast yet.

Your baby might still be sensitive to touch, but he likes steady, gentle, hands-on touch or skin-to-skin contact. You might be able to get involved in caring for your baby about now.

30-33 weeks

At this age, a baby’s organs are all maturing. A baby born now might not need much medical help.

Your premature baby’s movement is smoother and more controlled, and she’ll start to bend her arms and legs for herself.

Your baby’s deep sleep increases. His alert periods come more often, especially if the room is dim – he shuts his eyes tightly if it’s bright. When he’s alert, your baby might focus on your face or another interesting object, and he might show an obvious response to your voice.

Your baby might like eye contact, cuddling or talking during these times – but it’s still a good idea to keep it to one thing at a time. And you can also watch your baby’s body language for signs of stress.

Your baby might start to suck rhythmically and might show that she’s ready to suck to feed. Letting your baby smell and taste breastmilk gets her senses ready for breastfeeding. Gently rubbing around her lips and inside her mouth before feeds helps her get ready for the touch sensations of feeding from your breast.

If you see your baby putting his hand to his mouth, this means that he’s starting to soothe himself.

Your baby might still be very sensitive to touch and handling. It’s helpful to tell her what you’re about to do – for example, ‘We’re going to change your nappy now’. She can start associating your voice with what you’re doing.

33-36 weeks

Your baby is now approaching the date he was due to be born. But even when he’s reached 37 weeks, he isn’t necessarily like a full-term baby.

Your baby can now move more smoothly and bend her arms and legs. She can also move her head from side to side, and her muscle tone is stronger.

Your baby will be much less likely to experience apnoea.

Your baby’s states are clear – quiet sleep, active sleep, drowsy, quiet and alert, awake and fussy, or crying. His alert states are still quite short, but they’re getting longer and happening more often. He can have longer social times, and he can now turn away or close his eyes when he’s had enough.

Your baby is more likely to respond to sounds and noises in the same way from day to day. You might even know how she’s going to react when you say something to her.

Your baby probably still doesn’t cry much. But as he gets closer to full-term age, he’ll cry more often to let you know what he wants.

Your baby can usually start breastfeeding around this time.

Your baby might still be sensitive to touch and handling, although telling your baby what you’re about to do will help her relax over time.

37 weeks and beyond

Your baby might be ready to go home before his expected birth date. But it might take longer if your baby has had surgery or an illness.

The hospital will have health, growth and development goals for your baby to meet before you can take her home. These might include steadily gaining weight, feeding from your breast or a bottle at all feeds, and having no problems with apnoea.

Our article on going home with your premature baby has more information on how to prepare for your baby’s homecoming.