The Expert Guide to Pregnancy Screening Tests

As an expecting mother, you want to do everything you can to ensure you have a healthy pregnancy and your baby gets the best start in life. Pregnancy screening tests enable you to detect any health risks and disorders early, to allow you to make informed treatment choices or other important medical decisions. Follow our expert guide to identify which tests are mandatory and which are need-based.

The Necessary

Hepatitis B Screening

Hepatitis B can be transmitted from mother to baby. While not known to cause birth defects in infected infants, the disease can develop into cirrhosis of the liver and even liver cancer later in life. If the mother is a known hepatitis B carrier, a vaccine will be administered to the baby immediately after delivery to minimise the risk of infection.

Method: simple blood test
When: first prenatal visit

Syphilis Screening

If the mother has syphilis, the foetus can be infected through the placenta during pregnancy (known as congenital syphilis). Early treatment will lower the likelihood of stillbirth and deformities.

Method: simple blood test
When: first prenatal visit

HIV Screening

A mother who carries the Human Immunodeficiency Virus (HIV) can transmit the virus to her baby during childbirth and by breastfeeding. Early detection allows doctors to manage the risk of transmission by having a planned caesarean section. If you test positive, know that it does not mean you have Acquired Immune Deficiency Syndrome or AIDS; furthermore, with appropriate treatment, HIV is a manageable chronic condition.

Method: simple blood test
When: first prenatal visit

The Need-based

Thalassaemia Screening

Thalassaemia is a genetic blood disorder affecting the production of normal haemoglobin. Patients suffering from thalassaemia may require a blood transfusion every month throughout their lives and in severe cases, a bone marrow transplant is the only possible cure.

Method: you should already have undertaken a pre-pregnancy screening blood test that determines if you and your partner have the gene for thalassaemia. If both of you tested positive, it is recommended that you undergo chorionic villus sampling, where the obstetrician extracts a small amount of placenta tissue with a biopsy needle. These samples are then sent for testing.

Down Syndrome Screening

Women over 35 years of age have a higher risk of carrying a child with Down syndrome. It is recommended that expectant mothers above the age of 35 undergo a screening test to determine whether the baby is at risk. First Trimester Screening, sometimes called OSCAR (One-stop Clinic for Assessment of Risk for Foetal Anomalies), is the most common test to assess the risk of Down syndrome. A relatively new genetic test called NIPT (Non-Invasive Prenatal Test) is now available as well.

Both of the above are screening tests only, meaning they assess the risk of Down syndrome in an unborn child but cannot produce definitive results. Women at high risk must then decide whether to run a diagnostic test; note that procedures to obtain samples for testing, such as amniocentesis (withdrawing a small sample of amniotic fluid surrounding the foetus) or chorionic villus sampling, generally carry a small procedural risk of miscarriage. Your obstetrician will be able to advise on the best course of action.

Other Genetic Disorder Screenings

Based on your family and medical history, your doctor might recommend other tests to ensure you have all the information on hand to do what’s best for yourself and the baby. It is worth noting that genetic screenings are voluntary, not compulsory.