Down Syndrome Screenings

Tests can determine if your baby has a chromosomal abnormality

During pregnancy, a monthly visit to your healthcare provider ensures that both you and baby are healthy and thriving. Several routine tests will be done to monitor your health and keep a check on your baby’s development and growth.

Additional tests for chromosomal or genetic disorders are offered to those mothers who fall within the risk profile and further diagnostic testing may be necessary once screening test results have been received.

About Down Syndrome

Down syndrome is a genetic disorder which occurs when a baby receives an additional chromosome 21 – one from both parents plus an extra copy, caused by abnormal cell division. The condition causes several physical, intellectual and mental developmental delays and disabilities. It can also cause heart and gastrointestinal system complications as well as hearing loss, vision problems and other health issues. Severity differs among individuals. With early intervention and care, most people with Down syndrome can live happy, fulfilling and independent lives.

Testing and Risk Factors

During a routine antenatal visit, your doctor will discuss possible screening tests for Down syndrome and other genetic conditions. These tests determine if there is a likelihood that your baby could have a condition. Based on the results, further diagnostic testing may be required to provide a definitive answer. The decision to have tests done remains a personal choice.

• You will be offered pregnancy screenings in the following situations:
• Advanced maternal age (women over 35)
• History of chromosomal abnormalities (if you previously had a baby with a chromosomal abnormalities)
• Ultrasounds anomalies – abnormalities in your first pregnancy scan
• Family history of genetic disorders – maternal or paternal
• Multiple pregnancy – twins or higher order multiples
• Any other reason your doctor feels an NIPT should be done

Screening Tests

• Non-Invasive Prenatal Testing (NIPT) screens for Down syndrome and other chromosomal abnormalities. A sample of the mother’s blood is taken and used to analyse DNA from the baby (crossed over from the placenta) for various chromosomal conditions. The result indicates a low or high risk for the condition. The test can be done as early as nine weeks of pregnancy.
• The Triple Test or maternal serum test is a blood test that can be done between 15 and 20 weeks. The test measures the levels of three substances in a pregnant woman’s blood that could indicate neural tube defects and chromosomal abnormalities. If a fourth chemical is added, the test is called a quadruple test. A screen ‘positive’ indicates the need for additional testing.
• Nuchal Translucency (NT) scan is an ultrasound scan conducted between 11 and 14 weeks. A fold of skin at the back of the baby’s neck will be measured. A thicker than normal fold may indicate Down syndrome and further testing may be offered.

Always check what tests are covered on your within your medical aid plan. A NIPT is covered for members with medium and high-risk pregnancies. A Prescribed Minimum Benefits (PMB) form must be completed by your doctor, together with a letter of motivation and supporting information detailing your maternity risk condition.

Diagnostics Tests

These tests will only be considered if the above screening tests indicate a higher risk or positive result. Tests are not covered under the standard maternity care plan but your doctor can request them as part of the high-risk maternity benefits.

There is a small risk of miscarriage with diagnostic testing and your doctor will discuss this with you. Both tests take about 20 minutes. These results are final and no further tests will be required.

• Chorionic Villus Sampling (CVS) can be done from 10 weeks. A doctor, guided by ultrasound, uses a needle to remove a piece of placental tissue. The tissue is tested for chromosomal abnormalities
• Genetic amniocentesis is usually done between 15 and 20 weeks. Amniotic fluid is taken from the uterus using a fine needle and tested for several conditions

Preparing for and Receiving Results

Results may take a few days and it is normal to feel anxious and worried as you await them. Contact your dedicated Maternity Programme midwife for counselling and support.

It can be heart-breaking to learn that there is a problem with your baby and completely normal to experience a range of emotions, from anger to extreme sadness, after receiving a positive result for Down syndrome. Your healthcare provider will ensure that you and your partner receive all the necessary information to make an informed decision.

• The decision to keep your baby or abort the pregnancy is a personal one that only you can make
• Ask your doctor for a referral to a genetic counsellor for support and advice
• Before baby’s birth, learn as much as you can about Down syndrome, caring for a baby with the condition and early interventions and health care options for your child

Speak to your healthcare provider and medical aid how you can benefit from prenatal preventative screenings.

Resources: https://downsyndrome.org.za; https://www.mayoclinic.org/; https://www.webmd.com/; https://www.webmd.com/; https://www.pregnancybirthbaby.org.au/; https://www.nhs.uk/; https://www.mediclinicinfohub.co.za/