ANTENATAL DIAGNOSIS & COUNSELLING
Our aim is to provide comprehensive counseling and diagnostic testing for fetal defects. These are invasive tests designed to confirm chromosomal and genetic disorders. The decision as to whether to proceed with these invasive tests is unique for each couple. As a result, we are committed to providing the information and support that patients need to make the right choice.
These tests are usually offered to women who have an increased chance of having an abnormal baby eg women who have had a previous Down Syndrome child or other chromosomal disorders, women over 35 years old, or women who know that they or their baby’s father have an unusual chromosomal arrangement. It is not routinely offered to all women.
- Amniocentesis is a minimally invasive procedure in which a small amount of amniotic fluid is removed from the sac surrounding the fetus for testing. In this procedure, under direct ultrasound guidance, a fine needle is inserted into the womb through the abdomen. The fluid is then sent to a laboratory for analysis. Different tests can be performed on a sample of amniotic fluid, depending on the genetic risk and indication for the test.
- This is usually performed between 16-20 weeks of pregnancy.
- Amniocentesis is associated with a 0.03-0.5% risk of miscarriage.
- The results will usually be made available within 2 weeks. In the unfortunate instance in which you have an abnormal result, we will gladly discuss the diagnosis and implications with you and give you ample time to make an informed decision as to the best course of action.
Chorionic Villus Sampling (CVS)
- The placenta supplies essential nutrients and oxygen to the growing fetus and also removes toxic waste products from the fetus’s blood. The placenta is composed of chorionic villi which share the fetus’s genetic material.
- A sample of chorionic villi is removed from the placenta for testing during the CVS procedure.
- CVS can detect whether a fetus has chromosomal conditions such as Down syndrome and a host of other genetic disorders (eg. cystic fibrosis, sickle cell disease and thalassemia).
- The main advantage of CVS over amniocentesis is that it can be performed at an earlier stage (around 11-12 weeks) of pregnancy so the diagnosis can be made earlier.
- The results usually take about 7 to 10 days.
- CVS is however associated with a higher risk of miscarriage (0.5 – 1%) than amniocentesis.
DETAILED ANTENATAL ULTRASOUND SCANS
- From 18 weeks up to preferably before 24 weeks, a routine detailed fetal anomaly scan of the fetal spine, skull, brain, heart, lungs, kidneys, arms and legs is usually performed. This is done to ensure that all the major organs have developed normally.
- Most women give birth to normal healthy babies but all women have a small risk of delivering a baby with structural problems, especially with advancing maternal age. This scan detects the majority of significant structural abnormalities. In addition to looking at fetal anatomy, assessment of normal fetal growth and placental position are also checked
3D & 4D scans
- Our sister clinic GynaeMD Women’s & Rejuvenation Clinic performs 3D and 4D scans which are designed to give more lifelike views of what the developing fetus looks like. They are not meant to replace the routine second trimester screening scans. 3D and 4D scans are best performed between 26 to 30 weeks of pregnancy.
FETAL WELLBEING ASSESSMENT – growth scan, Doppler studies
These tests comprise of ultrasound scans, fetal movement charts and cardiotocography (CTG) and are designed to assess fetal wellbeing.
- Serial ultrasound scan are used to assess the estimated fetal weight, fetal parameters (head circumference, abdominal circumference, femur length), amniotic fluid levels and placental location. They are performed from 24 to 41 weeks to exclude fetal macrosomia or growth retardation. Colour doppler ultrasound on the other hand measure fetal blood circulation and umbilical cord blood flow to ensure the correct direction of flow and determine placental function.
- Fetal movement charts are performed by mothers at home by counting the number of fetal movements over a specific time period. This helps to reassure mothers that their baby is doing well. Mothers should then be seen if there is any decrease in fetal movement.
- The CTG is an electronic measurement of your baby’s heart rate which correlates to fetal wellbeing.