1.JUL.2021 5 MIN READ | 5 MIN READ

Prenatal screenings can help detect complications during pregnancy, which in turn, makes it possible for expectant mothers and their babies to receive the appropriate treatment and care.

Pregnancy is often associated with a rollercoaster of emotions. From feeling joyful and excited, to being anxious, it is no surprise that mummies-to-be have quite a bit going on in their heads as they prepare to welcome their bundle of joy into this world.

To ease anxiety and provide peace of mind about the baby’s development among mummies-to-be, prenatal screenings are available. Read on to find out more about the key ones to look out for.

Why are prenatal screenings conducted?

Prenatal screenings are offered to pregnant women of all ages. These screenings are mostly non-invasive, and through them, a mother-to-be will be able to understand how the pregnancy is progressing.

For example, prenatal screenings can reveal potential complications with the pregnancy that could put the health of mother and baby at risk. These tests can also detect birth defects or chromosome abnormalities early.

Prenatal screenings are not just for first-time mothers to get peace of mind; they are important for every pregnancy.

Why should I consider prenatal screenings?

Pre-natal screening
As you experience the milestones in each pregnancy, you’ll soon realise that each passing week is crucial for your baby’s development.

A healthy, normal full-term birth can be compromised due to pregnancy-related chronic conditions such as gestational diabetes, pre-eclampsia (high blood pressure, fluid retention and protein in the urine), infections and some genetic conditions. Some babies may have to be delivered prematurely due to circumstances such as uncontrollable maternal high blood pressure or other maternal medical conditions. Babies born pre-term are more likely to develop medical problems such as feeding difficulties, trouble breathing and have a low birth weight.

With regular antenatal visits and pre-natal screenings that include blood pressure and urine dipstick checks, many of these complications can be identified at an early stage and treated early to maintain the health of both mother and child.

Screenings to be considered

Medical advancements have made it possible for doctors to identify existing causes for concern during a pregnancy with the help of modern medical equipment.

Some of the common pre-natal tests and screenings can be scheduled at various points of your pregnancy. Let’s take a closer look at some of them:

Throughout your pregnancy

Ultrasound scan

The obstetrician and gynaecologist (O&G) will perform an ultrasound scan during your pre-natal visits. This is used to detect, check development of the foetus, measure its growth and physical structures. It can also help in identifying the location of your placenta.

Doppler ultrasound

During routine pre-natal visits, a Doppler ultrasound is used as well. This device uses sound waves to detect the movement of the baby’s blood vessels. The joy of hearing your baby’s heartbeat is actually the sound waves picked up by a Doppler ultrasound as it detects the movement of blood through the baby’s blood vessels.

Routine urine test

During pre-natal visits, mummies will be given a plastic cup to collect a sample of your midstream urine. Through a quick dipstick analysis of your urine sample, common medical conditions such as pre-existing diabetes, pre-eclampsia and urinary tract infections can be detected.

Blood pressure test

A nurse or your O&G will measure your blood pressure during your pre-natal visit. A high blood pressure reading could be a possible symptom of pre-eclampsia and your doctor might suggest additional tests for an accurate diagnosis.

First trimester (Weeks 1 – 12)

Non-invasive Prenatal Testing

Noninvasive Prenatal Testing
Non-invasive Prenatal Testing (NIPT) involves a simple blood test that is taken from an expectant mother from the 10th week of her pregnancy onwards. This test has zero risk of harm to the foetus. From the mother’s blood sample, the genetic laboratory is able to detect the minute free foetal DNA circulating in the mother’s blood. This can accurately detect Down Syndrome and genetic conditions with an accuracy of about 99.5%. The gender of the foetus can also be determined with the test.

Down Syndrome is a genetic condition in which a person has an extra chromosome 21, which can cause physical and mental developmental delays and disabilities. It is one of the most common genetic/chromosomal syndromes. The risk of a baby born with Down Syndrome increases with the mother’s age.


The Down Syndrome One-Stop Clinic for Assessment of Risk test, more commonly known as OSCAR, involves a nuchal translucency ultrasound scan conducted between 11 – 13 weeks of gestation and a lab test. It measures the thickness of the nuchal translucency located at the back of the baby's neck. Its accuracy is around 80% and it also has a zero risk of harm to the foetus.

Second trimester (Weeks 13 – 26)

Oral Glucose Tolerance Test

Oral Glucose Tolerance Test
As the name suggests, an Oral Glucose Tolerance Test (OGTT) measures your body’s ability to handle glucose. During this test, your blood will be drawn 3 times at 1 hour intervals to measure your fasting blood sugar level as well as your body’s tolerance to glucose after drinking a glucose solution. The test will be able to detect if you’re diabetic, pre-diabetic or have gestational diabetes. If any of these conditions are identified, careful management of the medical condition can help to reduce the risk of potential pregnancy complications, including pre-term birth. OGTT is usually done at 28 weeks of gestation.

Third trimester (Weeks 27 – 40)

Group B Streptococcus Test

A vaginal swab test can identify the presence of Group B Streptococcus (GBS) in the vagina. While the presence of GBS is usually asymptomatic, it can be transmitted to the baby during childbirth. GBS can cause serious lung and brain infections in the baby. If GBS is found to be present, your O&G will prescribe a course of antibiotics during labour.

Speak to your doctor

Ultimately, your O&G will be the best person to discuss these pre-natal screenings with. During your conversation with the doctor, consider asking the following questions to get a better understanding of the different screenings that will be conducted. They include:

How accurate are the results?

Are there any health risks towards both mother and baby if the mother were to be screened?

What happens if a medical condition or abnormality has been identified?

Pre-natal screenings are tools that can ease anxiety in parents-to-be, and help pregnant mothers receive appropriate pre-natal care. With the guidance of their O&G specialists, any necessary lifestyle changes during their pregnancy can be recommended to ensure that mummies and their unborn babies are healthy until the time they are due to be born.


Article reviewed by Dr Ting Hua Sieng, obstetrician & gynaecologist at Parkway East Hospital


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Ting Hua Sieng
Obstetrician & Gynaecologist
Parkway East Hospital

Dr Ting Hua Sieng is an obstetrics and gynaecology (O&G) specialist practising at Parkway East Hospital, Singapore.