Pregnancy ultrasound
What is a pregnancu ultrasound?
A pregnancy ultrasound is a painless, non-invasive imaging test that uses sound waves to create pictures of the developing fetus.
Pregnancy ultrasounds provide your doctor with valuable information.
Ultrasound is a safe examination for you and your baby.
Assessments are done on specific timelines of your pregnancy.
Should you have any other questions or concerns, please do not hesitate to ask the sonographer who will assist you and/or contact your obstetrician or GP.
First Trimester Early/Viability Scan
When
Between 6-10 weeks of pregnancy.
How
Transabdominal or transvaginal, depending on how far you are in the pregnancy.
Why
To make sure that the pregnancy is in the correct position (within the uterus)
To confirm the viability of the pregnancy. That magical moment when the heartbeat is detected as a bit of flicker in the foetal pole may be detected at the 6-week examination.
Your estimated due date (EDD) is calculated based on gestational age.
To determine the number of embryos/babies present
12-Week Scan
When
Can be done between 11 weeks 4 days to 13 weeks 6 days.
How
The scan is usually performed both transabdominal and transvaginal.
Why
To date the pregnancy accurately (via foetal measurement).
To diagnose multiple pregnancies. It is essential to know whether each twin has its own placenta or shares a placenta. In cases where a placenta is shared, your pregnancy will be monitored more closely.
To diagnose significant foetal abnormalities, some major abnormalities may be visible at this stage; however, a 20-week anomaly scan will still be necessary.
To assess the risks of Trisomy 21 (Down’s syndrome), trisomy 13 and 18 by assessing several markers, including nuchal translucency/neck fold and nasal bone.
Detailed Anatomical Scan
When
Detailed scans are done between 20 and 24 weeks and are often referred to as foetal abnormality scans.
How
The scan is usually performed trans-abdominally.
Why
A detailed anatomical scan is done to monitor the development of the organ systems and the physical structure of your baby.
The site of the placenta is determined to identify placenta previa (a placenta that lies close to or over the cervix).
The amount of amniotic fluid is checked - too much or too little is associated with certain conditions or abnormalities.
We also look for “soft markers”, which are subtle changes in your baby’s anatomy that may indicate an underlying chromosomal abnormality.
To evaluate blood flow to the uterus and between the placenta and your baby. Various blood vessels in your baby will be assessed using colour Doppler technology.
Growth Scan
When
Performed from 28 weeks of pregnancy and is used to monitor growth and screen for problems relating to the placenta and amniotic fluid. Your obstetrician/GP will assess whether it is necessary for a growth scan by considering your previous pregnancy history.
How
The scan is usually performed trans-abdominally; however, placental position check scans are performed transvaginally.
Why
Determine the growth, weight, and health of your baby
Placental position and appearance are evaluated.
Measurement of the amniotic fluid volume.
The blood flow to the placenta and various foetal blood vessels is evaluated with colour Doppler.
A quick surveillance of your baby’s vital organ anatomy will also be done to assess for significant abnormalities, which may only show in the third trimester.