The 19-20 week scan - Morphology scan
An ultrasound examination of your pregnancy is often recommended at 19-20 weeks gestation.
At this stage the sonographer or doctor can:
- Confirm that the fetal heart is beating
- Detect multiple pregnancies
- Measure the fetal size
- Assess the position of the placenta
- Check the volume of amniotic fluid around the baby
- Look for fetal abnormalities
Why scan the pregnancy at 19 weeks?
At 19-20 weeks gestation there are usually good views of the limbs as well as the internal organs.
It is sometimes called a "morphology scan" because we are looking at the fetal shape.
It is sometimes called a "structural scan" because we are looking at the structure of the fetus.
It is sometimes called an "anomaly scan" because fetal abnormalities are looked for at this time.
Why do I need a full bladder?
Fluid in the bladder provides a clear "window" to the pregnancy.
It also makes the uterus rise up from behind your pubic bone.
Your bladder does not need to be uncomfortably full, so feel free to empty some if you need to.
Can I find out the sex of the baby?
Ultrasound examination is never 100% accurate at determining the fetal sex.
But if you want to know the sex, please let us know at the beginning of the examination so that we have several opportunities to view the region, and improve our accuracy for you.
What sorts of abnormalities can be detected?Below is a list of different types of congenital abnormality, and how likely scanning is to identify each problem.
What happens if a problem is found?
If the scan finds a problem you will be told at the time of the scan that there is a problem and what we can see so far.
A full discussion of the problem may require further views, or views on another day when the baby is in a different position or is a bit bigger.
Often you may need to come back to the practice for a further scan and discussion with a specialist.
Most problems that need repeat scanning are not serious.
In about 5- 10% of scans we are unable to achieve every view that we need, and you will be asked to wait a little while of come back on another day.
How safe is ultrasound?
Ultrasound uses sound waves, not ionizing radiation like x-rays.
There have been many long term studies which have shown that ultrasound is completely safe to foetuses. There have been no adverse effects on babies from an examination before birth.
Follow-up studies have shown normal growth and development, normal eyesight and hearing and a normal range of school performance in children who had ultrasound examinations when in utero.