Your Pregnancy

This guide to your pregnancy tells you how your baby is developing each month. It also tells you a bit about how your body may be changing and how you might be feeling. Remember that 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 that babies come in two flavours, however - as most of you won't know what flavour you're getting - for clarity we will refer to your baby as "she".

Remember to check out our Pregnancy discussion boards here for further advice on your pregnancy - from how to combat morning sickness to where to find the best maternity jeans, other Mumsnetters have it covered. Plus, join our online antenatal club and share your experience with other Mumsnetters due in the same month as you.

Your pregnancy at 21 to 24 weeks

Most of your baby's organs are formed but they will need to develop more before they work properly. At 24 weeks a premature baby has a chance of surviving, although babies have done so earlier because medicine and technology advance every day.

Around this time you baby will be around 23cm long and weigh between 500 and 620g. She looks lean but already more babyish; she will start seriously putting on weight between 24 and 37 weeks - around 15g a day. Her cheeks are filling out slightly and her skin is becoming more red than pink, and less translucent. Her lips and tongue are formed and she will be getting used to them, licking her lips and maybe sucking her thumb if she bumps into it.

Her eyes may just have opened and they move quickly - she will blink if startled by a loud noise near your abdomen. Her hair and nails continue to grow. Nails can get quite long and need to be cut soon after birth to avoid your baby randomly scratching her or her face.

Perhaps the most important thing that happens to your baby at 24 weeks is that her lungs become more properly developed. They are still immature but the air tubes in the lungs are like a tree and they keep branching into smaller and smaller branches until they form tiny air sacs. At 24 weeks there are quite a few little air sacs. The cells that make up the walls of these tiny air sacs start producing a fluid that is essential to your baby's survival. The fluid is a fatty layer of liquid called surfactant and it keeps the tiny little airways open. These tiny airways need to be open when your baby is born so that she can breathe in enough oxygen. Around this time the blood vessels around the lungs also develop so they can pick up the oxygen the lungs have brought and take it round the body.

Your baby's immune system gets going during this period as she starts making white blood cells, which specifically attack bacteria and other infections.

Your baby now has the same sleep patterns as she will have when she is born. She will spend around six hours awake and 18 asleep - and will sleep in set positions. There is some debate among researchers as to what being awake really means. Certainly, there are times when your baby will respond to things happening outside it - to you perhaps - if you are startled by a loud noise. Some researchers think that your baby isn't really awake because the activity of her brain and nervous system is kept quiet while it is developing by hormones produced by the placenta. These hormones are thought to include prostaglandins and steroids.

The development of the human brain is incredibly complex as not only do cells in the brain and other nerve cells in the spine have to grow, but they also have to make intricate connections with other nerve cells. Your baby's highly specialised sense of taste and smell as well her sight are all being developed. The optic nerve, which tells the brain what your eye is seeing, is made up of over a million nerve cells that grow into the brain.

Your baby can hear in the womb and her hearing gets better as time goes on. She prefers lower, intense sounds to start with. There is some research to suggest that newborn babies respond to sounds they have become familiar with in the womb. Certainly newborn babies prefer the sound of their mother's voice and are calmed by it. There has been a trend to play babies classical music, read them great works of literature and take them to plays while still in the womb. These are all worthwhile activities but, however smart your unborn child is, she is unlikely to gain an enormous intellectual advantage from them. You'd have to suspect she would prefer you watched teletubbies.

How are you changing?

Blooming:

You may be blooming, The spots of early pregnancy will have gone, your skin will be glowing from those female hormones coursing through your body and your hair will shine (I am not sure why but it really does). You will feel vigorous and alive. After 6pm it is a different story but enjoy it while it lasts.

Itching:

You may find you have an overwhelming urge to scratch your abdomen and other parts of your body. This is probably due to the increased blood flow you have round your body. Scratching isn't great because it makes you want to scratch more and you can break the skin. Avoid wearing tight clothes because it makes it worse - light, loose cotton can help, as can taking your clothes off in the privacy of your own home. If you feel the itching is really bad, and/or you think your skin is looking yellow, see your doctor or midwife immediately as this can suggest a more serious problem than an itchy belly.

Forgetfulness, foggy headedness:

It is horrible to admit it but pregnancy does seem to make some women forgetful. Of course lots of people who are not pregnant forget and don't think clearly but you may notice that you aren't as quick as you were before you got this pregnant. It is as though a fog descends into your brain, making thinking sometimes a bit of a struggle. I think it is hormonal and patchy and does lift.

Remember, you can chat to other mums about all the "joys" of pregnancy on our Pregnancy discussion boards here.