Life stages
Timeline of conception
0 – 12 weeks
In the early stages of 0 – 12 weeks of pregnancy, after conception at 0 weeks once the cells have
been divided to form the embryo. Firstly at 4-5 weeks the foetus’s body along with its breathing and
digestive systems are forming along with the heart that starts to beat at 12 days.
Then at 5 weeks the embryo is 2mm long, the foetus’s nervous system is already developing along
with major organs preparing to form.
By 7 weeks, the brain is growing rapidly.
By 12 weeks the baby’s intestines will have grown. Nerve cells are now multiplying rapidly as well as
synapses in the brain. The foetus is now over 2 inches long and weighs half an ounce.
13 – 20 weeks
At the next stage of 13 – 20 weeks of the foetus being in the womb, the foetus has now developed a
second skin. Its head has increased in size and its reflexes have developed. At 13 weeks, it weighs 25
grams and is 10 inches long and is now able to move its head. The foetus can hiccup.
At 14 weeks, the foetus is about 85 mm long from head to bottom. The kidneys start to work. The
foetus starts to hear at 15 weeks.
By week 16 the foetus will be able to move the muscles of its face along with first signs of facial
expressions. The foetus is now able to flex its limbs. By the time of 17- 20 weeks the foetus has
become more human looking with eyebrows and eyelashes growing, weighing 150g, has fingerprints
on the fingers and the skin is coated in vernix which protects the skin.
21 – 28 weeks
From 21 weeks, the foetus has developed increasingly and is now heavier than the placenta
weighing around 350g and 38cm long. The foetus is coated in lanugo, soft hair thought to keep the
Timeline of conception
0 – 12 weeks
In the early stages of 0 – 12 weeks of pregnancy, after conception at 0 weeks once the cells have
been divided to form the embryo. Firstly at 4-5 weeks the foetus’s body along with its breathing and
digestive systems are forming along with the heart that starts to beat at 12 days.
Then at 5 weeks the embryo is 2mm long, the foetus’s nervous system is already developing along
with major organs preparing to form.
By 7 weeks, the brain is growing rapidly.
By 12 weeks the baby’s intestines will have grown. Nerve cells are now multiplying rapidly as well as
synapses in the brain. The foetus is now over 2 inches long and weighs half an ounce.
13 – 20 weeks
At the next stage of 13 – 20 weeks of the foetus being in the womb, the foetus has now developed a
second skin. Its head has increased in size and its reflexes have developed. At 13 weeks, it weighs 25
grams and is 10 inches long and is now able to move its head. The foetus can hiccup.
At 14 weeks, the foetus is about 85 mm long from head to bottom. The kidneys start to work. The
foetus starts to hear at 15 weeks.
By week 16 the foetus will be able to move the muscles of its face along with first signs of facial
expressions. The foetus is now able to flex its limbs. By the time of 17- 20 weeks the foetus has
become more human looking with eyebrows and eyelashes growing, weighing 150g, has fingerprints
on the fingers and the skin is coated in vernix which protects the skin.
21 – 28 weeks
From 21 weeks, the foetus has developed increasingly and is now heavier than the placenta
weighing around 350g and 38cm long. The foetus is coated in lanugo, soft hair thought to keep the
