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

8 min read

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 before taking an antacid, ask a pharmacist, midwife or GP and tell them you are pregnant. Sudden breathlessness or palpitations need checking straight away, and severe difficulty breathing or chest pain needs 999.

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.

Weeks to go	10
Length	About 39.9cm crown to heel
Weight	Around 1.3 kilograms
Size comparison	A large cabbage
Lanugo	Fine downy hair now beginning to fall away

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're 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 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. You can get some antacids from a pharmacist, but some are not suitable during pregnancy, so before taking one, ask a pharmacist, midwife or GP and tell them you are pregnant. Do not take antacids within 2 hours of taking folic acid or iron supplements. Heartburn that does not go away when you take antacid medicine can be a sign of pre-eclampsia, so call your midwife or maternity unit immediately (or 111 if you cannot get through), especially if you also have a severe headache, vision problems, pain just below your ribs, sudden swelling of your face, hands or feet, or vomiting. Your GP may also prescribe another medicine to reduce stomach acid.

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'). Breathlessness that comes on suddenly, being out of breath when you're lying down, or breathlessness with dizziness or heart palpitations needs to be checked straight away: call your midwife or maternity unit, or NHS 111. Call 999 or go to A&E if you have severe difficulty breathing, pain in your chest or upper back, a very fast heartbeat, or you pass out.

When to get help

Some symptoms in pregnancy can be a sign of something serious and need checking quickly. This is who to contact, and how soon.

Call 999 if:

you're bleeding from your vagina and the bleeding is heavy (soaking a period pad soon after putting it on), or you also have severe pain in your tummy, pain in your shoulder, or feel sick, faint, dizzy or lose consciousness
you think your baby is coming now and you have a strong urge to push (ask for an ambulance)
you have severe difficulty breathing (you're gasping, choking or not able to get words out) or your chest feels tight or heavy
you have pain and swelling in one leg and you also feel short of breath or have chest pain. A blood clot in the leg can travel to your lungs, which can be life-threatening
you have possible signs of sepsis, such as breathing very fast, being confused or having slurred speech, blue, pale or blotchy skin, a rash that does not fade when you press it, or a very high or very low temperature. Being pregnant makes sepsis more likely
you do not feel you can keep yourself safe (a mental health emergency is as serious as a physical one)

Always call 999 if you think it's a life-threatening emergency, no matter what stage of pregnancy you are.

Call your midwife or maternity unit now if:

your baby is moving less than usual, you cannot feel your baby moving anymore, or there is a change to your baby's usual pattern of movements
you have light bleeding or spotting, even if you have no pain or only mild tummy pain
you have stomach pain that is severe or does not go away after you've rested for 30 to 60 minutes, or stomach pain with regular cramping or tightenings, lower back pain, or pain when you pee
you're less than 37 weeks pregnant and you have a gush or trickle of fluid from your vagina (this could be your waters breaking), regular contractions or tightenings, period-type pains, or backache that's not usual for you
your waters break, even if labour has not started
you have signs of pre-eclampsia: a severe headache that does not go away with simple painkillers, vision problems (such as blurred vision or seeing flashing lights), pain below the ribs, sudden swelling of the face, hands or feet, feeling very unwell, heartburn that does not go away with heartburn medicines, or being sick (vomiting)
your skin is very itchy (for example, it keeps you awake at night), the palms of your hands or soles of your feet are itchy, or the itching is worse at night. This can be a sign of a liver condition called intrahepatic cholestasis of pregnancy (ICP) that needs urgent treatment
your breathlessness comes on suddenly, you're out of breath when you're lying down, or you're breathless and also have chest pain or feel dizzy
you have pain or swelling in one leg, usually in the calf or thigh. This could be a blood clot (deep vein thrombosis, or DVT), which is more likely when you're pregnant
you have a high temperature (38C or above), or you feel hotter than usual or shivery. A high temperature can be a sign of an infection, so it's important to get it checked

If your baby's movements change, do not wait until the next day: call immediately, even if it's the middle of the night. Do not use a home doppler to check the heartbeat yourself. Even if you hear a heartbeat, this does not mean your baby is well.

If you cannot reach them, or you're not sure what to do, call NHS 111.

Speak to your midwife or GP if:

you're worried about your mental health, or stress, anxiety or low mood are affecting your day-to-day life. If you need urgent help for your mental health, call 111 and select the mental health option, or ask for an urgent GP appointment

Go to sleep on your side. From 28 weeks, the safest position to go to sleep is on your side, either left or right. Research suggests that, after 28 weeks, falling asleep on your back can double the risk of stillbirth. This includes daytime naps. If you wake up on your back, just turn onto your side and go back to sleep.

Your week 30 checklist

This week:

Try the dietary strategies to manage heartburn.
Before taking an antacid, ask a pharmacist, midwife or GP, and tell them you're pregnant.
Sleep propped up if heartburn disturbs your rest.
Celebrate reaching 30 weeks.
Start thinking seriously about your hospital bag.

Sources & further reading

General information, not individual medical advice. Speak to your GP, midwife or health visitor about your baby’s needs.