Congenital Heart Defects (CHD)
Checking the heart is the most important part of our ultrasound scans. Fetal echocardiography is included with every scan from 12 to 34 weeks
What are Congenital Heart Defects or Congenital Heart Disease (CHD)?
A congenital heart defect (CHD) is a problem with the structure of the baby’s heart. This type of anomaly presents already at birth. The cardiac anomalies can involve the chambers of the heart, the septum between right and left parts of heart, the valves of the heart, and the vessels (arteries and veins) connected to the heart. CHD can disrupt the normal flow of blood through the heart, brain, body or the lungs.
There are different terms describing CHD and in majority of the cases they used as synonyms:
- congenital heart defects
- congenital heart disease
- cardiac anomalies
- cardiac abnormalities
- heart defects
- cardiac defects
- fetal cardiac conditions
5 reasons why CHD are the most important fetal abnormalities
1) Congenital Heart Defects (CHD) are the most common fetal anomalies. CHD are much more common that Down’s syndrome
According to data of British Heart Foundation one in every 145 babies born in the UK is affected by congenital heart disease (incidence rate 6.9 per 1,000 deliveries).
It is estimated that in the UK there are about 4,600 babies born with cardiac anomalies each year.
2) Cardiac anomalies are variable and many of them are severe
There are more than 100 different CHD. Some mild CHD will correct themselves spontaneously, whilst others can be treated non-surgically.
Complex cardiac anomalies like Hypoplastic Left Heart Syndrome can have serious short and long-term outcomes, and some like Transposition of the Great Arteries can be lethal if not treated immediately after birth.
British Heart Foundation survey shows that nearly 6 in 10 parents say they have been forced to work less or give up their careers entirely following their child’s cardiac diagnosis, with over half admitting this has put a significant strain on their family’s finances.
3) Most heart defects occur out-of-the-blue in low risk pregnancies, without any previous family history of CHD. Unfortunately, in many cases there is no identifying cause for the baby’s heart abnormality.
There are some situations that increase the risk of heart defect developments in babies, such as a previously conceiving a child with CHD, increased nuchal translucency thickness, maternal diabetes and some medications.
Unfortunately in majority of the cases there is no any identifying cause for the baby’s heart abnormality and children with CHD are commonly born for healthy parents, which have no any family history of congenital heart disease.
4) CHD are commonly undiagnosed before birth
There are different reasons why it is difficult to diagnose CHD before or even after birth.
Public Health England NHS Fetal Anomaly Screening Programme (2018) accepts as minimal standard prenatal detection of 50% serious cardiac anomalies. Common severe CHD which this document includes are:
- Transposition of the Great Arteries (TGA)
- Atrioventricular Septal Defect (AVSD)
- Tetralogy of Fallot (TOF)
- Hypoplastic Left Heart Syndrome (HLHS)
It means that one of two babies with those severe cardiac anomalies can be born without established diagnosis of CHD.
5) Prenatal diagnosis of CHD improves the baby’s outcome
It is well recognised that proper diagnosis of heart anomaly before birth will significantly improve baby’s outcome. Prenatal detection of CHD will give the parents an opportunity to:
- be referred to Fetal Medicine Unit for further counselling
- meet Fetal/Paediatric Cardiologist to discuss the type and severity of the heart condition and options of cardiac surgery
- to be aware about possible outcome for the child
- to be delivered in special tertiary centre delivery ward (usually large hospitals)
- baby to be transferred after delivery to Cardiac Surgery or Paediatric Cardiology department for treatment
What do we check during our fetal echocardiography for every baby:
At 12-13 weeks the fetal heart is about the size of corn grain, however, we check the presence and size of the four heart chambers and the presence and size of two great arteries and their crossing. The majority of severe heart anomalies can be detected; however it is impossible to see all the ‘holes’ in the heart.
After 20 weeks our baby’s heart examination checklist includes:
Heart position, size and heart rate.
- left atrium
- right atrium
- left ventricle
- right ventricle
- atrial septum
- ventricular septum
- mitral valve
- tricuspid valve
- foramen ovale
- aortic valve
- pulmonary valve
Great arteries and veins
- transverse aorta (aortic arch)
- pulmonary artery
- ductus arteriosus
- caval veins
- ductus venosus
- pulmonary veins