Tommy's PregnancyHub

Your premature baby's heart and blood flow

Finding out that your baby has a heart problem can be upsetting and worrying. But try to remember that many problems can be treated.

Your baby's heart pumps blood around their body, delivering oxygen and nutrients wherever they’re needed. The blood then passes back to the heart, which pumps it to the lungs where it gets a fresh supply of oxygen. This oxygen-rich blood passes back to the heart, before being pumped around the body again.  

Conditions related to the heart

Patent ductus arteriosus (PDA)

When babies are in the womb, their blood gets oxygen from the placenta. Their lungs don’t start working until the umbilical cord is cut after birth.  

Before birth, a blood vessel called the ductus arteriosus diverts blood away from the lungs. This blood vessel closes a few days after birth. In premature babies, it’s common for this closure to be delayed. This is known as patent ductus arteriosus (PDA). 

In most cases, this delay does not cause any problems and the blood vessel will often close by itself by the time your baby is the same age as a full-term newborn baby.  

However, in some cases, having a persistent PDA can make it difficult for a baby to come off respiratory support. In these cases, they may need medicine or surgery to close the blood vessel. 

Congenital heart disease (CHD)

The medical term ‘congenital heart disease’ describes a range of heart problems that affect how the heart works. They happen when the heart doesn’t develop properly in the womb. 

It is usually diagnosed by an ultrasound scan, called an echocardiogram (sometimes called ‘echo’ for short). 

Some types of CHD, such as small holes in the heart, don’t need treatment if they’re likely to improve on their own.

Other heart problems are more serious and need treatment. Surgery isn’t always possible or safe for very premature babies. If your baby is too small for surgery, the healthcare team will delay treatment to give your baby time to grow and develop.  


Bradycardia is a drop in a baby’s heart rate, which lasts 10 seconds or longer. It sometimes happens in premature babies who stop breathing for short periods of time (or apnoea).  

Bradycardia usually gets better when apnoea is treated. The healthcare team may use caffeine treatment or ventilation to reduce or treat apnoea.   

Low blood pressure (hypotension)

Low blood pressure is quite common in premature babies and doesn’t always need treatment. If your baby’s blood pressure falls too low and they have blood circulation problems, they may need treatment to increase the blood flow to their organs. The healthcare team may raise your baby’s blood pressure with extra fluids or medicines. 

What does this mean for my baby?

Don’t be afraid to ask the staff any questions you need to that will help you understand what is happening. This will help you make informed decisions about your baby’s care. Be involved with as much, or as little, as you feel comfortable with.

Find out more about your role in caring for your premature baby.

It can be very stressful if your newborn has heart and blood flow problems. Find out more about coping with this.

NHS Inform. Understanding how your heart functions. (Page last reviewed: 13 February 2020) 

MSD Manual. Patent Ductus Arteriosus (PDA). (Page last reviewed: Nov 2018.)
Pammi M (2020) Premature newborn care. BMJ Best Practice.
NHS. Congenital heart disease. (Page last reviewed: 12 June 2018. Next review due: 12 June 2021)
Chu PY et al. (2017) Congenital Heart Disease in Premature Infants 25-32 Weeks' Gestational Age. J Pediatr. 2017; 181: 37‐41.

Ballout RA et al. (2017) Body positioning for spontaneously breathing preterm infants with apnoea. Cochrane Database of Systematic Reviews 2017; Issue 1. Art. No.: CD004951. DOI: 10.1002/14651858.CD004951.pub3.
NICE (2019) Specialist neonatal respiratory care for babies born preterm. NICE guideline 124. National Institute for Health and Care Excellence.

Ballout RA et al. (2017) Body positioning for spontaneously breathing preterm infants with apnoea. Cochrane Database of Systematic Reviews 2017; Issue 1. Art. No.: CD004951. DOI: 10.1002/14651858.CD004951.pub3.

Ibrahim H, Sinha IP, Subhedar NV. (2011) Corticosteroids for treating hypotension in preterm infants. Cochrane Database of Systematic Reviews 2011, Issue 12. Art. No.: CD003662. DOI: 10.1002/14651858.CD003662.pub4.

Review dates
Reviewed: 23 August 2021 | Next review: 23 August 2024