- Performed at 12 weeks
- This scan is a combined blood test and ultrasound.
- The blood test “maternal serum test” measures naturally occurring proteins whilst the ultrasound measures the amount of fluid in the skin at the back of the baby’s neck.
- Together with other information supplied by the patient such as weight, allow calculation of risk factor for chromosomal abnormalities.
For your ultrasound and blood test
- It is recommended that patients wear loose comfortable clothing with easy access to the abdomen area (without zippers, buttons, jewellery or metallic accessories)
- Arrive 10-15 minutes prior to the appointment to complete paperwork
- The patient is required to drink fluids and refrain from going to the toilet, ensuring the patient is not uncomfortably full.
- There may be a need to have a blood test after the ultrasound examination and this will be discussed on the day.
- A sonographer will call the patient name and escort the patient through to the examination room
- The sonographer will provide information about the procedure prior to commencing the scan, providing ample time to answer any questions the patient may have.
- The patient will be asked to lay down on the examination table
- The abdomen is exposed and water-based gel is applied to the skin
- A transducer is glided gently over the abdomen by the Sonographer. Patients generally are able to view the image of the foetus on the imaging screen.
- The patient may be asked to perform different movements/positions during the procedure.
- The sonographer will take many measurements of the baby such as the head size, length of baby and the fluid at the back of baby’s neck, as well as looking at the placenta and the cervix.
- The patient may be asked to perform different movements / positions
- The patient will be asked if the sex of the baby would like to be known. This information will only be provided if requested.
Risks or Side Effects
- The ultrasound has no known harmful effects on the mother or the baby.
- If the test indicates an ‘increased risk’ of chromosomal abnormality, this does not mean there is a problem with the baby. In fact, an ‘increased risk’ is quite common (1-20 births). Further testing may be required or considered, such as chorionic villus sampling.
- Alternatively, a test indicating low-risk, means the risk of the baby having a chromosomal abnormality is low, but it does not mean that there is no risk.