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24 weeks pregnant

Week 24 is a big milestone. It might feel like nothing much has changed but this week your foetus becomes a baby so, in medical and legal terms, it’s a big leap.

By Mumsnet HQ | Last updated Mar 20, 2023

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Your baby at 24 weeks

This week your foetus is officially a baby. The law defines a live birth as a baby born at 24 weeks or later. Although she has a lot more growing to do before she is born, she is now considered 'viable'; she is very different developmentally from just a few days ago and, with specialist neonatal care, would have a much better chance of survival if born now than she would have done only a week previously.

  • What makes the difference to survival chances is that her lungs have become better developed. The air tubes in the lungs look like a tree – they keep dividing into smaller and smaller ‘branches’ until they form tiny air sacs at the ends. At 24 weeks there are quite a few little air sacs already in place, so while the lungs are still not mature, they are certainly getting there.
  • The main thing they are still waiting for is the cells in the walls of these sacs to start making a fluid called surfactant, which is essential to your baby's survival outside the womb. This fluid keeps the tiny little airways open, allowing newborn babies to breathe in enough oxygen. If your baby was born now she would need to be artificially ventilated as she hasn't made any surfactant yet.
  • About now, the blood vessels around the lungs also develop, so they can pick up the oxygen the lungs have brought and deliver it all around the body.
  • Your baby's sucking skills are pretty advanced but not yet advanced enough for her to be able to breastfeed if she was born now. She’ll have this sorted by week 35.
  • Her brain is maturing rapidly at this stage of pregnancy, and her brainwaves would already look similar to those she will have at full term. The brain cells that will allow her to have conscious thought are developing now, which means she can do clever things such as remember your voice and feel soothed by it.
  • She has had nervous reflexes for some weeks now, which is why you might have seen her jerk away from an ultrasound probe at one of your scans, but by this stage she also has major nerve routes that lead from her brain to virtually every part of her body. The growth of these higher-centre nerve cells and the connections between them start at around 24 weeks and continue after her birth. From this point on, the cortex, where thinking takes place, is becoming more mature.
  • From 24 weeks, your baby's face will make more obvious and also more subtle expressions. Researchers who examined video-taped foetal facial movements from 4D-ultrasounds found movements got more complex as the baby got older. At 24 weeks, babies could move one muscle in their face at a time, for example they could either stretch their lips or open their mouth. But by 35 weeks they could stretch their lips, lower their eyebrows and furrow their face between their eyebrows, all at the same time – a huge leap in muscle know-how.
  • The movements that start this week are the building blocks for her one day being able to smile, laugh, frown and more. Just as she practises breathing before she can actually take a breath, so she practises showing her emotions before she has any.

What size is the baby at 24 weeks?

At week 24, your baby is around 30cm long and is the size of an ear of corn. She weighs around 600g.

How is your body changing at 24 weeks pregnant?

From week 21 to week 26, your uterus is rising up above your belly button.

Your lower rib cage fans out by as much as 5cm to make room for your womb, which can be uncomfortable and make your back bigger – you may need to adjust your bra, or go and get measured for a new one again.

Pregnancy symptoms in week 24

Here are some of the changes you can expect at 24 weeks.

Round ligament pain (again)

With your womb rising up higher and higher, things get a good stretching again around this time. The uterus is attached to the round ligament which is joined to the wall of your abdomen. You might find you get stretching pains down the sides of your abdomen as these ligaments are pulled like they’ve never been pulled before.

Dry eyes

Hormonal changes in pregnancy can cause your eyes to feel dry and gritty. Try not to rub them as this will make it worse and you might cause an infection. Bathing them with a bit of cotton wool dipped in cold water can help soothe them, and you can also try using a humidifier at home, or just employing the old-fashioned method of buying a few pot plants and opening a window to keep the atmosphere a little more humid.

Things to think about during week 24 of pregnancy

This is a fine time to health check your diet and make sure you’re getting plenty of the good stuff and are still on top of which foods to avoid, too.


Calorie-controlled dieting is not recommended in pregnancy but watching what you eat most definitely is. Try not to put on too much weight. Most women gain 8-14kg, most of it after week 20 as that’s the time when your baby grows most and you’re laying down fat stores for breastfeeding.

While you shouldn’t restrict what you eat during pregnancy, it’s a good idea to think about making healthier choices, eating the right foods and getting regular exercise. Too much weight gain in pregnancy can put you at greater risk of pre-eclampsia, high blood pressure or gestational diabetes, as well as less serious but pretty irritating things like stretch marks.

Baby names

Now your foetus is officially a baby it’s probably time to start thinking about a name for her. Choosing a baby name can be a long process, particularly if you and your partner have quite different tastes. If one of you is a Scheherazade type and the other desperate for a baby Jane, it’s as well to start the discussions now.

Can you fly at 24 weeks pregnant?

If you're hoping to squeeze in a holiday before the arrival of your bundle of joy (if it's your first baby, then enjoy those undisturbed cocktails by the pool while you can), you'll be pleased to know that you can fly at 24 weeks.

In fact, now could be the best time to go, as the fatigue and morning sickness of the first trimester will (hopefully) be behind you. What's more, your bump is still just small enough not to cause a lot of discomfort on the flight. Airlines have their own rules about when you can no longer fly during pregnancy, but most will allow you to fly up until about 36 weeks pregnant.

What's next: 25 weeks pregnant