PRENATAL GENETIC COUNSELLING

What is prenatal genetic counselling?

The reasons for testing and the different types of tests done during your pregnancy can be confusing. Prenatal genetic counselling helps you understand the complexities of prenatal tests, and the interpretation of the results. As these tests determine the risk of your baby having a birth defect or genetic condition, you are provided with emotional support to help you make informed medical and personal choices regarding your pregnancy.

What are prenatal tests?

Prenatal tests are performed during pregnancy and provide valuable information about your baby’s health. These tests determine the potential (or risk) for your baby to be born with a birth defect and/or a genetic condition.

Why is prenatal testing offered?

• Everyone is at risk of having a child with a birth defect (±5% of births in South Africa).
  
  
  
• Prenatal testing is used to identify women with high risk pregnancies (high risk for a baby with a birth defect or genetic condition) to ensure immediate access to appropriate support.
  
  
  

What is your risk for a birth defect or genetic condition in your pregnancy?

• The basic risk for a birth defect or genetic condition in your pregnancy is defined by your age (maternal age). The different tests performed during your pregnancy (prenatal tests) are used to adjust this basic risk to identify pregnancies at a significantly increased risk. 
  
  
  
• This risk may differ if you have a personal or family history of a genetic disorder, chromosomal abnormality, birth defect or developmental delay.  Your age risk will be adjusted based on the actual condition diagnosed and associated inheritance (how it runs in the family).
  
  
  

Who would benefit from prenatal genetic counselling?

• You would benefit from prenatal genetic counselling if you can say yes to one of the following:
  
  
• Pregnant and over the age of 35 years, often referred to as advanced maternal age (AMA).
  
  
• Family history of a genetic disorder, chromosome abnormality, birth defect or developmental delay.
  
  
• From an ethnic group at higher risk for a genetic condition.
  
  
• Personal or family history of miscarriages or stillbirths.
  
  
• Couples that are close relatives or first cousins.
  
  
• You have a medical condition, or take medication that could affect the baby.
  
  
• Exposure to substances that may cause birth defects  i.e. radiation.
  
  
• Infections during pregnancy that may cause birth defects i.e. rubella, chicken pox, or cytomegalovirus.
  
  
• Use of alcohol or drugs during your pregnancy.
  
  
• A prenatal screening test(s) has indicated an  increased risk for a chromosomal abnormality or birth defect.
  
  
• You are worried about your chances of having a child with a birth defect or genetic disorder.
  
  

DIFFERENT TYPES OF PRENATAL TESTS

There are two types of prenatal tests, screening and diagnostic, and they differ based on the outcome:

• Screening tests are non-invasive and identify pregnancies at a greater risk for a birth defect or genetic condition, but they are not not conclusive.  If your risk is increased you will probably be offered a prenatal  diagnostic test.
• Diagnostic tests are mostly invasive tests and confirm the presence or absence of a specific genetic condition.