Obstetric Ultrasound Scans

Obstetric ultrasound employs sound waves to generate an image of your baby inside the uterus. Ultrasound is a very efficient, safe and painless imaging modality to examine the fetus and as such, is considered to be an indispensible obstetric tool and plays an important role in the care of every pregnant woman.

Viability scan
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Viability scan is best done before 10 weeks of pregnancy. Apart from diagnosing and confirming early pregnancy, this scan can also confirm the location of pregnancy to be within the uterus.

Dating scan
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Dating scan done between 8 to 13 weeks of pregnancy is most accurate in the prediction of the due date of the baby. This is done by measuring the length of the baby from the head to the buttocks (crown-rump length). Presence and type of multiple pregnancies can be accurately diagnosed with this scan as well.

First trimester screening for down syndrome

Also known as OSCAR (One Stop Clinic for the Assessment of Risk), the First Trimester Screening assesses the risk of the baby inside your uterus having Down Syndrome. The most accurate way of estimating the risk of carrying a Down Syndrome baby is by combining the information from (1) the age of the mother, (2) the findings from an ultrasound scan at 11 to 13+6 weeks pregnancy (the nuchal translucency scan) and (3) information obtained from the levels of two hormones (free ß-hCG and PAPP-A) in the mother’s blood. In pregnancies affected by Down syndrome, there is a tendency for the levels of free ß-hCG to be increased and PAPP-A to be decreased. The nuchal translucency scan is an ultrasound scan performed between 11 and 13+6 weeks of pregnancy, during which the fluid at the back of the baby’s neck (the nuchal translucency) is measured. All babies will have some fluid here but in babies with Down Syndrome, the fluid tends to be increased. The fetal anatomy will also be examined as there are some physical abnormalities that may be diagnosed at this stage of pregnancy. The fetal skull and brain, the nasal bone, the arms, the legs, the stomach, the spine, the abdomen and the bladder will be examined. This scan should be done by a trained personnel accredited by the Fetal Medicine Foundation.

Fetal anomaly screening scan 
The Fetal Anomaly Screening Scan is a detailed scan that is done at around 18 to 21 weeks. The main purpose of this scan is to examine the structural anatomy of the fetus to check for major anomalies; paying special attention to the brain, face, spine, heart, lungs, stomach, bowel, kidneys, limbs, genitalia and umbilical cord. The fetus is also examined for minor variations of normal anatomy (soft markers) which are found more commonly in babies with chromosomal abnormalities. In addition, the growth of the fetus, the amount of amniotic fluid, placental position and uterine blood flow are also assessed during the scan.

Growth scan
Growth scans can be done in the second half of pregnancy to assess the growth and well-being of the baby. During the scan, the baby’s head, abdomen and thigh bone are measured, the amount of amniotic fluid around the baby is assessed, the baby’s activity is observed and the position of the placenta is recorded.

Doppler ultrasound scan for fetal surveilance
Doppler Sonography is a special ultrasound application used to evaluate the blood flow between the placenta to the fetus like the Umbilical Artery; as well as blood flow within major fetal vessels like the Middle Cerebral Artery and the Ductus Venosus. For fetuses that are detected not to be growing as well as expected, Doppler Sonography is used to detect early signs of oxygen deprivation. The findings will help to assess the condition of the fetus and to time the delivery of an intrauterine-growth-restricted fetus. Other important applications of Doppler Sonography are the detection of fetal anemia and management of pregnancies complicated by twin-twin transfusion syndrome.

Cervical length surveillance and cervical cerclage
In women at high risk for preterm delivery (cervical incompetence, multiple pregnancies, previous preterm birth, abnormalities of the uterus or previous cervical surgery), the length of the cervix can be measured using the ultrasound scan. Shortened cervical length may increase the risk of preterm delivery. In cases that are indicated, a stitch may be placed at the cervix (cervical cerclage) to prevent premature dilation.

3D and 4D ultrasound scans

3D Ultrasound Scan provides a three dimensional image of your baby. 4D Ultrasound Scan is four – dimensional – the fourth dimension being time. 4D takes three – dimensional 3D ultrasound images and adds the element of time to the process. This allows you to see your unborn baby in amazing real time detail. Around 12 weeks into the pregnancy, you can see your whole baby. The best time to see the baby’s facial features is between 25 to 32 weeks of pregnancy. 3D and 4D ultrasound scans are specially meant for mothers who want a keepsake photo or video of their unborn child.

All ultrasound scans are done with a monitor within view of the mother and her partner, allowing the mother to view the fetus and watch as the ultrasound is completed. The mother will be given a keepsake of the baby. For 3D/4D scans, we will record a short DVD of your baby for you to take away with you.

Incorporated in 2005, Singapore Medical Group (SMG) is a private specialist and primary healthcare provider with a network of more than 20 medical specialties. The Group is committed to its promise of providing patient centred medical care and experience to every individual. SMG has more than 27 clinics and a growing network of SMG Associates clinics all across the island.