30/06/2020
๐ถ YOUR ANATOMY SCAN ๐ถ
This detailed ultrasound scan, sometimes called the mid-pregnancy or anomaly scan, should be carried out between 18 and 20+6 weeks/days pregnant.
The scan checks the physical development of your baby, although unfortunately it cannot pick up every condition.
The 20-week scan is carried out in the same way as the 12-week scan. It produces a 2-dimensional (2-D) black and white image that gives only a side view of the baby. The NHS screening programme doesn't use 3-D or colour images.
The scan is a medical examination and youโll be asked for permission before it is started.
Make sure you understand what's going to happen, and feel free to ask any questions at any point.
The 20-week scan is offered to everybody, but you donโt have to have it if you donโt want to.
๐ง What does the scan look for?
The 20-week scan looks in detail at the baby's bones, heart, brain, spinal cord, face, kidneys and abdomen.
It allows the sonographer to look for 11 rare conditions. The scan is a screening tool and not diagnostic so cannot find everything that might be wrong.
The 11 specific conditions are:
anencephaly
open spina bifida
cleft lip
diaphragmatic hernia
gastroschisis
exomphalos
serious cardiac abnormalities
bilateral renal agenesis
lethal skeletal dysplasia
Edwards' syndrome, or T18
Patau's syndrome, or T13
In most cases, the scan will show that the baby appears to be developing as expected, but sometimes it might be suspected or found that something is outside โnormalโ parameters & more investigations might be needed.
Some conditions can be seen more clearly than others. For example, some babies have a condition called open spina bifida, which affects the spinal cord.
This can usually be seen clearly on a scan, and will be detected in around 9 out of 10 babies who have spina bifida.
Some other conditions, such as heart defects, are more difficult to see. Scanning only picks up 50% of babies effected by heart defects.
Some of the conditions that can be seen on the scan, such as cleft lip, will mean the baby may need treatment or surgery after they're born.
In a small number of cases, some very serious conditions are found โ for example, the baby's brain, kidneys, internal organs or bones may not have developed properly.
In some very serious, rare cases where no treatment is possible, the baby will pass away soon after they're born or may die during pregnancy.
๐ง What happens at the 20-week scan?
Most scans are carried out by specially trained staff called sonographers. The scan is carried out in a dimly lit room so the sonographer can get good images of the baby.
You'll be asked to lie on a couch, lower your skirt or trousers to your hips and lift your top to your chest so your abdomen is uncovered.
The sonographer or their assistant will tuck tissue paper around your clothing to protect it from the gel, which will be put on your tummy.
The sonographer then passes a handheld probe over your skin to examine the baby's body. The gel makes sure there's good contact between the probe and your skin. A black and white image of the baby will appear on the ultrasound screen.
Having the scan does not hurt, but the sonographer may need to apply slight pressure to get the best views of the baby. This might be uncomfortable.
The sonographer needs to keep the screen in a position that gives them a good view of the baby. The screen may be directly facing them, or at an angle.
Sometimes the sonographer doing the scan will need to be quiet while they concentrate on checking your baby. But they'll be able to talk to you about the pictures once they've completed the check.
The appointment for the 20-week scan usually takes around 30 minutes.
Sometimes it's difficult to get a good picture if the baby is lying in an awkward position or moving around a lot, or if you're above average weight or your body tissue is dense. This does not mean there's anything to worry about.
You may need to have a full bladder when you come for the appointment. The doctor or midwife looking after you will let you know before you come. If you're not sure, you can contact them and ask.
