How do babies breathe in the womb?

Your baby won’t take their first proper breath until they are born. While they are still in the womb, the placenta will give them the oxygen they need and take away the carbon dioxide they produce through the umbilical cord.

During pregnancy, your baby’s lungs are filled with fluid and don’t inflate with air until birth. When your little one does arrive, their first breath will often sound like a gasp.

This is nothing to worry about – it is just your newborn reacting to the sudden change in their environment and filling their little lungs up with air.

At what stage can babies breathe on their own?

Throughout your pregnancy, your baby’s lungs will be developing. This process is usually not complete until your little one is close to reaching full-term at 36 weeks, which is why babies who are born prematurely can often need help with their breathing.

Between around 24 week and 36 weeks of pregnancy, their lungs will start to develop alveoli – small air sacs which fill up with oxygen. But as long as the umbilical cord and placenta is working properly, your baby will get all the oxygen they need in the womb and will only need to breathe air when they are born.

If your doctor or midwife believes you are in premature labour or are at risk of going into labour early, you may be given steroid injections to speed up your baby’s lung development and help them grow stronger.

Once your baby’s lungs are fully developed, they still cannot breathe in the womb as they are surrounded by amniotic fluid and their lungs are full of liquid. They can however practice breathing from about 10 to 12 weeks of pregnancy.

These practice breaths are not crucial for survival and won’t actually provide your baby with any oxygen. However, they do help them get used to the actions they will need to take to breathe once they are born. 

Can babies drown in the womb or during a water birth?

Your baby’s lungs are meant to be filled with fluid during pregnancy so they cannot drown. They will get all the oxygen they need from the placenta and umbilical cord.

If there is a problem with the placenta or umbilical cord, this can cause babies to be deprived of oxygen which can cause serious issues.

If you choose to have a water birth, your baby can be safely delivered underwater. Your baby will continue to get all the oxygen they need from the umbilical cord and won’t take their first breath until they are taken out of the water and the change in environment encourages them to inhale the air around them.