At six months, your baby is 21cm long. The blood vessels in her lungs are developing to prepare for birth.

Your body
The increase in blood circulation under your skin means you should be looking healthy – blooming if you're lucky. The good news this week is that your baby is now considered medically 'viable': if she were to be born now, with the help of modern technology, she would stand a reasonable chance of survival. But don't worry – she's still got a lot of growing to do, and so have you!

Sitting comfortably
If you use public transport, by now people should be leaping up to offer you a seat. If they are not, you could try placing one hand in the small of your back, closing your eyes and swaying gently while sticking out your bump as much as possible or simply ask for a seat by telling the person your pregnant.

Have a nap
Help your legs take the strain by wearing comfortable shoes and putting your feet up as often as possible. Research shows that you'll get the most benefit from napping at around 2-3pm, so try to get your head down for 20 minutes or so every afternoon. Take a late lunch and check out the facilities at work – you may be pleasantly surprised to discover a spare sofa you can use.

Gum trouble
However gently you brush and floss your teeth, you may still be experiencing bleeding gums. This is caused by pregnancy hormones – in particular, the increase in oestrogen – which make the blood vessels more permeable, leaving gums swollen and inflamed. There's not much you can do about this: don't stop brushing – your teeth are particularly susceptible to infection now, so good oral hygiene is essential. Have regular check-ups with your dentist too, but remember to tell your dentist that you're pregnant: some procedures, such as x-rays, should be postponed until after the birth.

Your baby
She now weighs about 530g and is 21cm long from crown to rump. The blood vessels in her lungs are developing to prepare for birth.

A 20 minute nap is all you need for an energy boost.

Your beating heart
Your baby can now hear all sorts of noises, from your heart pumping, to your stomach rumbling and blood circulating around your body.

Busy baby
You may have noticed that your baby now has regular periods of activity (how could you fail to notice?) and rest. Once established, this pattern may continue after the birth, so you may like to keep a record of it for a few days to see how it compares with your newborn's sleep pattern.

Breech in confidence
At this stage, it's common for your baby to be breech – head up – in the uterus. She's most comfortable in this position, so don't worry if your midwife tells you this is how she's lying: most babies turn round later in pregnancy and assume the head down position, which makes the birth far easier for both of you.