First trimester pregnancy screening
12-week scan · nuchal translucency scan · dating scan · first trimester combined screening
An ultrasound of the baby at 11 to 13 weeks plus a blood test for the mother. Together they check how the baby is growing and the chance of some chromosome conditions.
Offered to all pregnant women at 11 to 13 weeks.
⏱ Duration: the ultrasound usually takes 20 to 30 minutes, plus a blood test
Be sure to tell your doctor
How to prepare
- Timing. Strictly between 11 weeks and 13 weeks and 6 days. After that, this screening is no longer done.
- Bladder. Ask your clinic. Sometimes you are asked to come with a full bladder, sometimes the opposite.
- Blood test. The blood test is usually done on the same day, or 1 to 2 days before the ultrasound, as the lab requires.
What to bring
- Your pregnancy record or referral
- Results of past ultrasounds
How it goes
- You lie on your back with your belly uncovered
- The doctor puts on gel and looks at the baby through your belly
- The baby's size, heartbeat, and the fluid at the back of the neck are measured
- Sometimes a vaginal probe is used for more accuracy
- Blood is taken from a vein, if not done yet
What you'll feel
- It does not hurt. You will feel the probe pressing
- You can see your baby on the screen and hear the heartbeat
Afterwards
- A program calculates the risks from the ultrasound and blood test. Results come in a few days
- A high risk is not a diagnosis. The doctor will explain which follow-up tests are needed
Contact a doctor straight away if
- Bleeding or pain low in the belly: see a doctor without waiting for the screening
Common questions
Is ultrasound harmful to the baby?
No. Ultrasound has been widely used in pregnancy for a long time, and it has no radiation.