The prenatal diagnostics available at Mount Elizabeth Hospital range from early trimester screening to mid-trimester serum screening for Down syndrome. Whether the fetus is suspected of having a birth defect, growth restriction, or if the pregnancy is high risk due to the mother’s physical condition and age, we are fully equipped to diagnose and monitor the situation. We use high quality 2D fetal imaging, growth surveillance and biophysical fetal assessment, as well as fetal blood sampling or amniotic fluid aspiration to detect any infection or inherited disorders.
Our prenatal diagnostics services include:
Foetal Anomaly Scan
An ultrasound scan at around 18 - 20 weeks to check for fetal congenital anomalies, this is sometimes called the mid-pregnancy scan. At this stage, the fetus is large enough and the major organ systems are also adequately formed to be inspected. During the scan, the baby will be checked on the following:
- Shape of the head and the brain structures
- Correct alignment of the spine and that the skin covers the spine
- Long bones of the limbs, hands and feet, fingers and toes
- Cleft lip
- Size and symmetry of the heart chambers, heart valves and the orientation of the great blood vessels
- Kidneys and bladder
In addition, the position of the placenta and the sufficiency of amniotic fluid are also checked. This thorough examination of the fetal structures pick up major abnormal feature so that early action can be taken.
Also known as the amniotic fluid Test (AFT), this is mainly performed to diagnose chromosomal abnormality. Common abnormalities include Down syndrome, Edwards syndrome and Turner syndrome. AFT is also performed to detect sex of the fetus, fetal lung maturity and fetal infection.
When doing AFT a small amount of local anaesthetic is first administered to relieve the pain felt during the insertion of the needle. Using the guidance of ultrasound, the needle is inserted through the mother’s abdomen, through the uterus wall and into the amniotic sac. The needle will be placed safely away from the fetus and will extract 20ml of amniotic fluid.
For prenatal genetic diagnosis, the fetal cells in amniotic fluid sample will be cultured, fixed and stained, and the chromosomal make-up will be examined under the microscope. The amniotic fluid will be cultured for any growth of micro-organism for diagnosing in utero fetal infection.
Chorionic Villus Sampling
Chorionic villus sampling is a prenatal test done between 10 - 12 weeks of pregnancy to discover genetic defects in the fetus. A small sample of placental tissue (chorionic villus) is removed for analysis and can be performed in two ways, either through the cervix or through the abdomen. One benefit of chorionic villus sampling is that the test can be done very early in the pregnancy, resulting in early intervention for any genetic deficiency in the fetus.
Fetal Blood Sampling
Fetal blood sampling (FBS) is usually done between 20 - 23 weeks of pregnancy. During the procedure blood is drawn from the umbilical cord of the fetus. Similar to the AFT and CVS, a small hollow needle is inserted through the abdomen and uterus into the umbilical cord. FBS is generally conducted to detect for chromosomal disorders, genetic diseases and viral infections.