Week 13 of pregnancy
Week 13 is the start of the second trimester of pregnancy.
The ovaries or testes have now developed inside the baby's body. The genitals are forming on the outside of the body. It is still too early to see the sex on an ultrasound scan.
Bones are forming and hardening in the baby's arms and legs. Their digestive system had been developing outside their body. By now, it has moved to its permanent location inside the tummy.
The baby weighs around 25g and is about the same size as a peach.
Week 14 of pregnancy
At 14 weeks, the baby is about 85mm long from head to bottom. Their body is covered in a fine hair called lanugo.
The baby swallows small sips of amniotic fluid.
The kidneys start working to make pee. The pee goes back into the amniotic fluid.
The baby has grown to about the size of a lemon.
Week 15 of pregnancy
Around this time, the baby will start to hear. They may hear muted sounds from the outside world and any noises your digestive system makes. They will also hear the sound of your voice and heart.
The baby's eyes also start to become sensitive to light. Even though their eyes are closed, they may sense a bright light outside your tummy.
The baby has grown to about the size of an apple.
Week 16 of pregnancy
The baby can now move the muscles in their face. This starts to look like facial expressions. But the baby does not control this.
The baby's lungs are also developing. Amniotic fluid goes in and out of the lungs. This prepares the lungs for breathing air.
The nervous system continues to develop. This means the muscles in the arms and legs can flex. Around this time, the baby's hands can reach each other. Their hands can form a fist and hold each other when they touch.
The baby has grown to about 110mm long and around the size of an avocado.
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