Pregnancy Week 30: Heartburn, Breathlessness, and Your Baby's Growing Brain

Quick answer: At 30 weeks your baby measures about 39.9cm crown to heel and weighs around 1.3 kilograms, with a brain that now fills the skull. Heartburn is common because the growing uterus pushes the stomach up; smaller meals and propping up at night help, and antacids such as Gaviscon are safe in pregnancy, though always check with your pharmacist or midwife first. Breathlessness is normal, but sudden severe breathlessness, chest pain or palpitations need prompt medical advice.

What parents need to know

You're 30 weeks pregnant — just 10 weeks to go! Your baby is now doing well-organised movements and beginning to position themselves for birth. Meanwhile, you may be experiencing some of the more challenging symptoms of late pregnancy, including heartburn and breathlessness. The good news is that there are effective ways to manage both.

How big is your baby at 30 weeks?

Your baby now measures approximately 39.9cm from crown to heel and weighs around 1.3 kilograms — about the size of a large cabbage. They are continuing to gain weight rapidly as fat builds up beneath the skin.

What's happening with your baby?

Your baby's brain is growing so quickly that it now fills the skull completely and is developing more and more of the characteristic folds and grooves that increase its surface area. The bone marrow is fully responsible for red blood cell production. The lanugo — the fine, downy hair that has covered your baby's skin since around week 14 — is beginning to fall away, though some babies are still born with patches of it, particularly on the shoulders and back. Your baby's eyesight is developing, and they can distinguish between light and dark. Some research suggests babies may even be able to track objects at this stage.

Managing heartburn in pregnancy

Heartburn and acid reflux are extremely common in the third trimester. The growing uterus pushes the stomach upwards and the hormone progesterone relaxes the muscle at the bottom of the oesophagus (the lower oesophageal sphincter), allowing stomach acid to escape upwards. This causes the burning sensation in the chest or throat that is characteristic of heartburn.

To help manage heartburn: eat smaller, more frequent meals rather than large ones; avoid spicy, fatty, or acidic foods; don't lie down for at least an hour after eating; prop yourself up with extra pillows at night; wear loose, comfortable clothing; and avoid eating late in the evening. Antacids such as Gaviscon are safe to use in pregnancy and can provide relief, but always check with your pharmacist or midwife before taking any medication. If heartburn is severe or not responding to antacids, your GP or midwife may be able to prescribe a stronger medication that is safe in pregnancy.

Breathlessness in the third trimester

As your uterus grows, it pushes against the diaphragm, reducing the space your lungs have to expand fully. This can make you feel breathless, particularly when bending down, climbing stairs, or doing anything physically demanding. This is normal and will usually improve in the final weeks of pregnancy when your baby drops lower into the pelvis (known as 'engaging' or 'lightening'). If you experience sudden severe breathlessness, chest pain, or palpitations, seek medical advice promptly as these can occasionally indicate more serious conditions that need assessment.

Your week 30 checklist

This week:

• Try the dietary strategies to manage heartburn.
• Keep a stock of antacids approved by your pharmacist.
• Sleep propped up if heartburn disturbs your rest.
• Celebrate reaching 30 weeks.
• Start thinking seriously about your hospital bag.