Tommy's PregnancyHub

Your premature baby: heart and blood flow

It’s worrying if you discover that your baby has a heart problem, but most defects are treatable and some do not even need treatment.

Your baby's heart beats very quickly to pump the blood around her body, delivering oxygen and nutrients wherever they are needed. The heart and its functions are closely linked to breathing, in the cardiovascular system.

Congenital heart disease (CHD)

Sometimes the heart does not develop normally in the womb, leading to congenital heart disease. If this is the case the precise problem will be diagnosed by a special ultrasound scan called echocardiography.

Some forms of congenital heart disease do not need treatment, such as small holes in the heart, while others are life-threatening and will need surgery to correct the problem.

Patent ductus arteriosus

Around the time of birth a blood vessel that is used to divert blood away from the lungs when the baby is in the womb (the ductus arteriosus) closes so that blood can be pumped to the lungs from the moment of birth. It is common for this closure to be delayed in premature babies. This is known as patent ductus arteriosus.

In most cases, this delay does not cause a problem to the baby and the duct will often close by itself by term equivalent age. However, in a small number of cases it can cause problems.

If your doctor thinks this is the case then they may use a medicine to try to close the duct, or may suggest surgery.


Sometimes when babies have periodic breathing or apnoea their heart slows down. This is known as bradycardia. Usually it is very short-lived and gets better as soon as the apnoea resolves. The team will try to prevent bradycardia by preventing apnoea with respiratory support and by giving caffeine.

Low blood pressure (hypotension)

Occasionally a premature baby or sick term baby's blood pressure is too low. It is important that the baby's blood pressure remains at the right level and does not fluctuate too much. If it drops too low, this could affect brain development, so the healthcare team may raise her blood pressure with extra fluids or drugs.

The following organisations can give you more information about the topics covered in this section.

  1. PubMed Health Medical Encylopedia (accessed Oct 2016) Patent Ductus Arteriosus, PubMed Health,
  2. BMJ Best Practice (accessed Oct 2016) Premature newborn care, Treatment, details,
Review dates

Last reviewed: 5 October, 2016
Next review: 5 October, 2019