OBSTETRIC ULTRASOUND SCANS
Obstetric ultrasound scans refer to scan done during pregnancy. Ultrasound scan machines make use of sound waves to generate an image of your baby inside the uterus. Unlike X-ray, it does not have any radiation; hence ultrasound scans are very safe for the fetus. In addition, ultrasound is a very efficient and painless way to examine the fetus and as such, is considered to be an indispensible obstetric tool and plays an essential role in the care of every pregnant woman.
In our clinic, the images of the scans are projected onto a TV monitor within the view of the pregnant woman and her partner. This allows the parents-to-be the precious opportunity to see and bond with their unborn child in comfort.
Viability scan is best done before 10 weeks of pregnancy. This scan is important as it not only can confirm an early pregnancy, it can determine if the location of pregnancy is within the uterus. One potential life-threatening complication of pregnancy is ectopic pregnancy where the pregnancy is located outside the uterus. Ectopic pregnancies are usually located in the fallopian tubes. If the ectopic pregnancy is diagnosed early enough, medical or surgical treatment can be instituted such that the fallopian tubes can be kept intact.
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 (FTS) 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 risk of a mother carrying a Down Syndrome baby is calculated 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 like the nuchal translucency, the presence or absence of nasal bone, the fetal heart rate etc and (3) the levels of two hormones (free ß-hCG and PAPP-A) in the mother’s blood.
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. 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 medical 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 19 to 21 weeks of pregnancy. The main purpose of this scan is to examine the structure 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 and placental position are also assessed during the 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 surveillance
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. 3D is akin to taking a photo of the fetus while 4D is like taking a video. This allows you to see your unborn baby in amazing real time in great 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.