Your pregnancy: weeks 33, 34, 35, 36, 37

Weeks 6-8 | Weeks 9-12 | Weeks 13-16 | Weeks 17-20 | Weeks 21-24 | Weeks 25-28 | Weeks 29-32 | Weeks 33-37 | Weeks 39-40

This guide to your pregnancy tells you how your baby is developing week by week. It also tells you a bit about how your body may be changing and how you might be feeling. Remember, not all babies develop exactly like each other so this can only be a general guide: you should ask your doctor or midwife for any specific information about your pregnancy. We all know babies come in two flavours, but - as most of you won't know what flavour you're getting - for clarity we'll refer to your baby as 'she'.

How your baby is growing | Your baby's size | How your body is changing

How your baby is growing

Your baby will have a firm handshake and would already be able to look you in the eye, although her vision improves once she is out of the womb. She needs to learn how to adjust the lens in her eye to focus on near and far objects properly. She's still putting on weight, but not so rapidly as she realises space is now at a premium.

By now, your baby is likely to have shifted so that she's lying in the head down position. Her head will be in your pelvis and her legs up against your ribs. This tends to happen earlier on in first pregnancies when you still have abdominal muscles to give some direction to your baby - in later pregnancies your baby may be swimming around slightly longer. This head down position gives you more room to breathe as there is less pressure on your diaphragm, but you may still feel short of breath.

Your baby's lungs are still developing. The number of tiny air sacs (essential for oxygen to get into the body via the lungs) are increasing all the time. Their walls are getting thinner so the oxygen can get through faster, and there is less of a gap between the walls of the air sacs and the tiny blood vessels that carry the oxygen round the body. Before birth your baby's lungs are full of fluid because she swallows amniotic fluid. This fluid is full of protein; chloride and a clever substance that we all make called surfactant that keeps the air sacs open.

As your baby practises breathing in your womb, she breathes in amniotic fluid; this helps the lungs develop and gives the muscles in the chest, which will do all the breathing when your baby is born, something to do. When your baby is born, her breathing will squeeze this fluid out of her lungs and through her mouth and also into the blood vessels of the lungs where it will be absorbed.

The amniotic fluid your baby swallows also helps develop her gut and bowels: it contains up 10-15% of the protein your baby needs for growing them. Your baby's bowels will take a while to develop - which is why babies aren't born able to tuck into pie and chips.

Other organs like the liver also take a while to mature. At birth your baby's liver may struggle to break down a substance called bilirubin (some of which the body makes naturally - it's the stuff that in high levels makes babies look a bit yellow). Most bilirubin is got rid of through the placenta.

Your baby has learnt to suck - something she will rely on for months after she is born - and her sucking ability is already incredibly strong.

Meanwhile, her heart rate has been slowing down from its original gallop in the 20th week to a more sedate average of 142 beats a minute. It speeds up when she moves her arms or legs and seems to peak between 8am and 10am and slow down between 2am and 6am.

Your baby's size

Your baby is now putting the finishing touches to her development: she will measure between 31cm and 34cm and weigh between 2,200g and 2,900g. At 37 weeks the distance around your baby's head and stomach will be the same.

How your body is changing

You may still be luxuriating in the perfect pregnancy and not suffering from any of the side effects of carrying a baby in your womb. Conversely, many women feel tired and that they have backache. During this time, you may notice some of the following as well:

• Braxton Hicks contractions

These contractions were named after the doctor (Dr John Braxton Hicks) who first described them in the 19th century. They are infrequent tightening feelings across your abdomen. They are not the start of labour because they do not become more frequent and regular and they do not get worse. In real labour, the time between each contraction gets shorter and the pain does get more intense. However, many women can't tell the difference. Even if this is your second or third pregnancy, you can mistake them for the real thing as they can be stronger and come earlier in subsequent pregnancies. If you don't know and the pain is strong then see your doctor or midwife. This is especially true if your baby is under 37 weeks, as she may need some medical help.

Sometimes these contractions can be strong enough to make you stop what you are doing. They can last for quite a few minutes. There is nothing that is known to really stop them. Some women say walking helps, others that it can bring these contractions on. Having a bath may help. If you feel these contractions are more than twinges, that you have any other symptoms, such as bleeding, cramps that feel like bad period pains or any fluid loss from your vagina - phone your doctor or midwife.

More about Braxton Hicks

• Swollen feet

You may notice your fingers, feet and lower legs swelling during pregnancy, especially if it's hot weather. This is because your blood volume has increased significantly to deal with the demands of carrying and nutritionally supporting a baby: fluid seeps out of your blood vessels into the surrounding tissues and pools there for a while. Everything will return to normal after your baby is born, but meanwhile you will need to change your shoes. Swimming is helpful, as is raising your legs higher than the level of your heart (so above your hips) whenever you sit down.

Swelling can be a sign of a serious condition called pre-eclampsia, which usually also causes headaches and high blood pressure. If you have any symptoms - other than just mildly swollen feet and ankles - you should see your midwife or doctor.

Remember, you can chat to other mums about all the 'joys' of pregnancy on our Pregnancy discussion boards. And once your baby is born, get posting on the Talk forums in Being a parent.

Weeks 6-8 | Weeks 9-12 | Weeks 13-16 | Weeks 17-20 | Weeks 21-24 | Weeks 25-28 | Weeks 29-32 | Weeks 33-37 | Weeks 39-40