Private screening for congenital conditions

Congenital abnormalities – also referred to commonly as ‘birth defects’ – are those that babies are born with. They are most commonly the result of random abnormal development but can sometimes be inherited. 

All babies are unique, and the ways in which a condition will affect their life will vary. When a baby is born with a condition at birth, they can experience structural defects, typically of the heart or other organs, or have a chromosomal condition, such as Down’s syndrome. We are able to offer you a test for both these types of congenital abnormalities in pregnancy. 

Chromosomes are the "blue prints", or "DNA", that make us what we are. Humans have 23 pairs of chromosomes, or 46 in total. A small number of birth defects are caused by chromosomal anomalies, and while some of the differences that might accompany these – such as a condition that affects the heart – can be addressed, managed, or treated after a baby has been born, an underlying chromosomal anomaly will always be present.

Chromosome abnormalities affect the number of chromosomes so there may be too many (the usual case) or too few.

• Down’s syndrome: This is a condition in which the foetus develops an extra chromosome or an extra piece of a chromosome. This extra copy changes how a baby's body and brain develop, and can lead to some level of learning difficulties in life.
  
  Chromosomes are present in nearly every cell of our bodies; therefore, Down’s syndrome can affect any organ system, and it can affect digestive, speech and other physical systems. Each child with Down’s syndrome is unique, and their abilities will be, too. 
  
  In the vast majority of cases, Down's syndrome does not run in families. While anyone can have a baby with Down’s syndrome, your chance increases as you get older. 
   
• Edwards’ syndrome and Patau syndrome: In these chromosome conditions, the effect on organ function is so severe that the baby may not survive the pregnancy, or may have significant issues following birth. 
  
  Trisomy 18 (Edwards’ syndrome) and Trisomy13 (Patau syndrome) are associated with a high rate of miscarriage. Babies with these conditions are typically affected by significant brain abnormalities and often have congenital heart defects as well as other birth defects. 

Most structural birth defects are random anomalies that can involve any organ system; for example, the brain, spine, face, heart, kidneys, extremities, lungs or gastrointestinal tract. These may be either major or minor. 

In most cases, the cause of the defect is unknown and is not linked to an abnormality in the chromosomes – it simply reflects the complexity of development from a single cell to a fully functioning person. 

A detailed foetal ultrasound scan, when performed by a skilled clinician, can detect the vast majority of major birth defects. For example, a high-quality ultrasound can detect nearly all open spinal defects, so that a normal result virtually eliminates the possibility of a significant spinal condition. 

While major anomalies involving other organ systems can also generally be identified, some minor defects may remain undetected. 

Screening for congenital anomalies is a routine part of your pregnancy care, and ultrasound scanning  alongside blood tests are a highly effective way of assessing the possibility of birth defects. 

• 12 week nuchal translucency pregnancy scan: This 'first trimester combined screen' is carried out between week 11 and 14, and can include a blood test for even greater accuracy.  
• 20 week anatomy and anomaly pregnancy scan: This comprehensive 'second trimester scan' is carried out between 18 and 22 weeks.

Non-Invasive prenatal tests (NIPTs): If you are in a high-risk category, in terms of family history or if you are over 35, or if you simply want a more accurate test, you may decide to have a non-invasive prenatal screening test, such as Illumina. This is an advanced screening test, not usually offered on the NHS, and offers a high degree of reassurance. 

The range of chromosome anomalies tested for varies from one NIPT to another, and has been increasing. 

We are one of very few private clinics in the UK currently offering a choice of different tests to suit different needs. Learn more about the differences between the various tests we offer.

The most accurate test for a chromosomal condition such as Down's syndrome, Edwards' syndrome or Patau's syndrome is an amniocentesis. This test involves removing and testing a small sample of cells from amniotic fluid – the liquid that surrounds the baby in the womb.

However, it is an invasive test, and we only recommend it in the unlikely situation that a non-invasive test reveals a very significant risk, as the procedure itself carries a very small risk of miscarriage.