Facts about your new baby

Your new baby is an amazing little creature with a strong survival instinct and a strong need for food, safety and comfort…


average weight of a newborn baby

7.7lb (3.5kg)

changes to your baby’s heart & lungs

  • As soon as your baby is born,there are some major changes taking place in his body as he needs to breathe for himself and pump the oxygen rich blood around his body.
  • Immediately after birth, his lungs inflate and blood travels from the right side of the heart to the lungs for oxygen, back to the left side of the heart and into the aorta, the main artery of the body.
  • The Ductus Arteriosus (which forces blood to bypass the lungs in pregnancy), Ductus Venosus (which forces fetal blood to bypass the liver in pregnancy) and the umbilical vessels close and form ligaments.

your baby’s skull

  • Your new baby’s skulls has bony plates with two soft spots (fontanelles) to allow the plates to overlap, so the skull can change shape to fit down the birth canal.
  • The fontanelle at the back of your baby’s head will close by 6 weeks and the fontanelle at the front of his head will close by about 18 months.

baby brain

  • Your new baby’s brain weighs about 14oz and it will be 3lb by the time he is two years old.
  • Your baby is born with about 200 billion brain cells but with very few connections – these develop as your baby grows


Your new baby will be able to see your face from about 20cm away – so at the breast or in the crook of  your arm for a cuddle. Anything further away could look fuzzy, although he will turn towards the light  and will like the contrast between light and dark.

eye colour

Your baby’s eye colour may not be permanent until they are one


It is normal for this to be very random and chaotic because your baby will probably wake up easily and here’s why:

  • Your baby will experience a 50 minute sleep cycle (whereas an adults is 90 minutes)
  • Most of your baby’s sleep is active sleep – this is a light sleep with noises, movements and fluttering eyelids. This makes up about 25 minutes of your baby’s sleep cycle and he could wake easily during this stretch.
  • Then he will fall into quiet sleep, a deeper sleep when your baby is harder to wake up – his brain activity calm, his body is still and his breathing is deeper.
  • As soon as he comes out of this deeper sleep he will move into quiet sleep again and this is when he could wake up needing food or comfort.


These are your baby’s most common reflexes…

Root reflex – when the corner of your baby’s mouth is touched he will turn his head and open his mouth to begin feeding.
This reflex lasts about 4 months.

Suck reflex – when the roof of your baby’s mouth is touched by the nipple or bottle teat, he will start to suck.

Moro reflex – also called the startle reflex because it often happens when your baby is startled by a loud sound or a sudden movement. Your baby will throw back his head, throw out his arms and legs and then pull them back in again.
This reflex lasts until your baby is about 5-6 months old

Tonic neck reflex – when your baby’s head is turned to one side, the arm on that side will stretch out and the opposite arm will bends up at the elbow. Also called the fencing position, this lasts until your baby is about 5 – 6 months old.

Grasp reflex – stroking the palm of your baby’s hand will cause him to grasp your finger.
This lasts until your baby is about 5-6 months old.

Babinski reflex – if you stroke the sole of your baby’s foot, his big toe will bend backwards and the other toes will fan out.
This lasts until your baby turns two.

Step reflex – also called the walking reflex your baby will look like he is taking steps when you hold him upright on a solid surface.
This reflex lasts about 2 months.

Tongue thrust reflex  – this protects your baby from choking. When something is placed on his tongue, he will automatically thrust his tongue forward. This will gradually disappear between 4-6 months when he is getting ready for solid food.


University of Rochester Health Encyclopedia

The Pregnant Body Book

What Every Parent Needs To Know

Dr Sears


Written by Janine Smith | Birth, Baby & Family
A specialist in pregnancy, birth and early parenting


About Janine 664 Articles
As an experienced and qualified practitioner, I specialise in pregnancy, birth and parent support - my aim is to listen, inform, support and reassure when needed. I have worked with parents since 2002 and I set up Birth, Baby & Family in 2011 to provide good information, different voices and links to the best products and services for families.