Your unborn baby week by week: Third trimester development

As you move into the third trimester of your pregnancy, you're probably picking out names and getting yourself and your home ready for his or her arrival on b-day.

But what is your baby up to?

Find out what he or she can already do even before birth ...

Your growing baby: Third trimester

Week 29
 Her head is getting bigger now too, it is attempting to keep up with her fast growing brain! As the brain runs out of space it becomes wrinkled and covered with folds and grooves.
Week 30
 You are probably in your last few weeks of work and your baby is working hard too. He has grown to 33cm long and has little eyebrows. At this stage babies begin to stock up on iron. Boys' testes descend into the scrotum.
Week 31
 Bone marrow is making her red blood cells now instead of her liver. The baby starts breathing in some of her surrounding amniotic fluid in preparation for breathing when she is born.
Week 32
 As the lungs are closer to being fully developed by this stage, babies born at 32 weeks or later have a much better chance than those more premature. Early babies born now usually just require some help to breathe and need to be kept warm.
Week 33
 He weighs nearly 2kg at 33 weeks and is running out of room! Your unborn child can still turn round but hopefully he will decide to keep his head pointing down from now on ready for his impending birth.
Week 34
 Her hearing should be fully developed around now. On the subject of hearing, your family could try pressing their ears to your tummy to see if they can hear the baby's heartbeat. It is possible if you get the right place!
Week 35
 Fat is growing under his skin now and he's getting plumper all the time. He starts to look more pink and his skin will appear less loose and wrinkled as he fills out.
Week 36
 Her bones are getting harder towards the end of your pregnancy but her skull bones stay soft to help with delivery. She is now making cortisone which helps her to breathe when she is out in the air.
Week 37
 By now most of the lanugo and vernix has gone from the skin and been swallowed by the baby. This is why his first poo (called meconium) will be so different to any other poo you will see!
Weeks 38 - 40
 If your baby arrives from now onwards it would be considered full term. On average babies weigh between 2.7 to 4.1kg at birth. It gets quite cramped in there when your baby is fully grown - this baby certainly looks keen to have a nice stretch!
Week 40
 Overdue babies are bigger than others of course, and their skull bones are harder, which can make giving birth more difficult. They are often more alert and lively too, and probably extra keen to meet you as they have been waiting longer!
Week 28
 Congratulations, you are in the third and final trimester of your pregnancy! Your baby should now weigh about 1kg. The hair on his head will now be getting longer and thicker.