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24 weeks pregnant

Your baby at 24 weeks

Foetus at 24 weeks pregnant

Your foetus is officially a baby. The law defines a live birth as a baby born at 24 weeks. Although you don't want your baby to be born now, she is very different developmentally from even a week ago.

  • Perhaps the most important thing is that her lungs have become better 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.
  • But the cells in the walls of these sacs haven't started making a fluid that is essential to your baby's survival. This fluid is called surfactant and it keeps the tiny little airways open. This allows your newborn baby to breathe in enough oxygen. If your baby was born now she would need to be artificially ventilated as she hasn't made surfactant yet. 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 sucking, while good, is not quite good enough. She needs to be 35 weeks to be able to suck milk from your breast.

  • Your baby's brain is maturing rapidly. Her brainwaves now are similar to those she will have at term. The brain cells that will allow her to have conscious thought are developing, which may explain her ability to remember your voice and be soothed by it.
  • Up until now she has had nervous reflexes, which is why she jerks away from an ultrasound probe, but now she has major nerve routes that come from her brain to distant parts 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. A report from the Royal College of Obstetrics and Gynaecology says that magnetic imaging techniques have recorded babies responding to what they see and hear at 28 weeks, but that already at 24 weeks the cortex, where thinking takes place, is becoming more mature.
  • From 24 weeks onwards, your baby's face will make more obvious and subtle expressions. Researchers examined video-taped foetal facial movements from 4D ultrasound machines. They found movements got more complex as the baby got older. At 24 weeks babies could move one muscle in their face at a time. They would stretch their lips or open their mouth. By 35 weeks they could stretch their lips, lower their eyebrows and furrow their face between their eyebrows - all at the same time.
  • Your baby may not be able to speak when she is born but she will have the muscle know-how to cry and soon to laugh. Just as she practises breathing before she can take a breath, so she practises showing her emotions before she has any.
  • You may feel your baby hiccoughing as she swallows amniotic fluid and tries to breathe at the same time. 

Your body at 24 weeks pregnant

Weight watching 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 your baby grows and you lay down fat stores for breastfeeding.

A study in the BMJ says that 20-40% of women gain more than the recommended amount of weight in pregnancy. The researchers found that women who watched their diet were 3.84kg lighter than other women at term and were less likely to get pre-eclampsia, high blood pressure or gestational diabetes.

The diets were not calorie controlled but were healthy ie a low-glycaemic diet with unprocessed whole grains, fruits, beans and vegetables and a diet with a maximum of 30% fat, 15–20% protein and 50–55% carbohydrate.

Your growing uterus Between 21 weeks and 26 weeks your uterus rises above your belly button - the muscles in the uterus have got bigger. The uterus is attached to the round ligament which is joined to the wall of your abdomen. You get stretching pains down the sides of your abdomen as these ligaments are pulled as never before.

Ribs 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.



Pregnancy Encyclopedia book coverIllustrations taken from The Pregnancy Encyclopedia, £25, published by DK.

Disclaimer: The information in the pregnancy calendar is for general information and is not intended as a substitute for the medical advice of your own doctor or antenatal team. Not all babies develop at the same time and in the same way, so this week-by-week guide may not always match your own experience. If you have any worries, consult your antenatal team or GP.

Last updated: 3 months ago