102. Adjusting To The Changes

During the nine months of pregnancy your baby will go through many changes.

First trimester

0-4 Weeks

Your baby is called an embryo and is about 0.6 cm (1/4 inch) long or about the size of a grain of rice.
The embryo sticks to (implants in) the wall of your uterus
The placenta, amniotic sac and fluid begin to form
The early structures of the brain have started to form
You may notice that your period will be late

5-8 Weeks:

The embryo is about 2.5 cm (1 inch) long and weighs less than a grape
The heart starts beating
The head and brain are taking shape
Internal organs are forming
Teeth begin to develop
Arm and leg buds are beginning to show
The spine starts to show and bones begin growing
The spinal cord starts to develop nerve connections (synapses) that will allow your baby to move his limbs and fingers, hiccup, stretch and yawn

9-13 Weeks:

Your baby is now called a fetus, is about 7.6 cm (3 inches) long and weighs about as much as a tube of lipstick
The eyes, ears and nose have formed
The mouth has formed, with lips, tongues and tooth buds
The hands, fingers and fingerprints, knees, ankles and toes have formed
The reproductive organs have formed
Your baby has started to kick (you can’t feel it yet)
Your baby sucks their thumb and makes breathing motions
At around 12 weeks you may be able to hear your baby’s heartbeat through a fetal doppler
Your baby’s basic brain cells (neurons) are developing very quickly, becoming more organized and are starting to connect to each other

13-18 Weeks:

Your baby is about 12.5 cm (5 inches) long (curled up, they are about the size of a tennis ball)
Your baby weighs about 90g (3 oz)
Your baby is starting to look more like a real baby
Your baby’s body is covered with lanugo (fine hair)
Your baby’s hair and eyebrows begin to grow
Your baby’s fingernails and toenails have developed
Your baby’s taste buds and inner ears have formed (they can hear you too!)
Your baby can roll over within the uterus

19-22 Weeks:

Your baby will grow up to 18 cm (7 inches) during these 4 weeks. By the end of 22 weeks they are about 25 cm (10 inches) long (about the distance from your elbow to your wrist)
Your baby weighs about 250g (8-9 oz)
Your baby is covered with a protective cream (vernix) that helps to conserve heat and moisturize their skin. It will also help them pass through your birth canal
Your baby kicks, twists and turns. They may be most active when you are sitting still
Your baby can grasp and suck
Brain cells are continuing to develop more connections with each other
By 20 weeks your baby’s brain and nervous system is developed enough to react to sound and light

23-26 Weeks:

Your baby is now about 32 cm (13 inches) long (roughly the distance from your elbow to your fingertips)
Your baby weighs around 1kg (2 lbs) or as much as a small melon
Your baby moves around. You can feel when they are high up in your abdomen or low down in your pelvis
Your baby has finger and toe prints
Your baby will develop a pattern of sleep and activity
Your baby can hiccup
Your baby’s lungs aren’t yet fully developed
Your baby’s eyelids can open and close
Your baby is growing, but looks skinny
Your baby’s brain stem (which controls heart rate, breathing, blood pressure and other vital functions) is now developed

26-31 Weeks:

Your baby is about 38 cm (15 inches) long
Your baby weighs about 1kg (2-3 lbs), or as much as a small bag of sugar
Your baby will be moving a lot. Other people will be be able to see and feel them moving too
Your baby’s eyes open, and he has eyelashes and eyebrows
Your baby will sense light and sound
Your baby can tell when you’re moving
Most of your baby’s billions of brain cells are formed
The outer part of the brain (cerebral cortex) continues to develop. The grooves and folds of the brain are formed.

32-35 Weeks:

Your baby is about 46 cm (18 inches) long
Your baby weights 2.25-2.5 kg (5-5.5 lbs), or as much as a small bag of flour
You might feel your baby’s heels or elbow sticking into your ribs
Your baby is building up layers of fat under the skin that will provide warmth after birth
Your baby’s brain is growing quickly now. Talk and sing to them
Your immunity to some diseases is being passed to your baby to protect them during the first few months
The soft hair on your baby’s body is going away

36-40 Weeks

Your baby is about 55 cm (20 inches) long
Your baby weights 2.7 – 4 kg (6-9 lbs)
Your baby may be gaining 28g (1 oz) a day
Your baby is not considered pre-term if they are born after 37 weeks
Your baby’s skin is pinker and becomes less wrinkled as they gain weight
Your baby’s lungs are ready to breathe air after 37 weeks
Your baby has less room to move, so movements will feel different to you. Ask your healthcare provider for more information about your baby’s movements
Your baby may scratch their face with their fingernails