20 week scan

At this point you’re halfway through you pregnancy and ready for your 20 week scan, also known as the anomaly scan.

This big moment in your pregnancy is similar to the dating scan that you had a few weeks ago, where the sonographer covered your tummy in gel and used a scanner to show you an ultrasound on a screen.

The 20 week ultrasound is the second of two pregnancy scans that you will have in a normal pregnancy (although you will have additional scans if the doctors have any concerns or detect a problem). The name, however, is a bit of a misnomer because you can have this scan anytime between 18 weeks pregnant and 21 weeks pregnant.

Keep reading the following article to learn other facts about the 20 weeks scan that may surprise you!

Are there risks involved with the 20 week scan?

First, you should know that ultrasounds during pregnancy are completely safe for you and the baby; there are no known health risks or side effects to having the pregnancy scans that you will need to check on your baby’s development during pregnancy.

However, there is one risk that you should be aware of before having the 20 week scan or anomaly scan. First, sometimes the sonographer can make a mistake when identifying the sex of the baby. In fact, some medical centres have a policy of not revealing the gender unless the parents specifically ask to know, just to help avoid mistakes. It can be a major inconvenience to expecting parents to learn that their baby is a different gender many weeks later into the pregnancy.

What will you see in the anomaly scan?

Whether the gender is clear or not, your little one will appear on a screen in a black and white image. It will look a little bit like an X-Ray, with the bones showing up as white, the tissues and organs as grey, and the amniotic fluid as black. 

The whole process of the 20 week scan should take about 20 minutes and your medical care providers will tell you what they are seeing as they look. In some medical centres they will allow the patients to watch the entire process, but at others they only show the baby in the first few minutes and then provide pictures of the scans to the parents later.

What are the costs of the 20 week scan?

All required pregnancy scans, including the 20 week ultrasound, should be completely paid for by NHS within the UK. However, the costs associated will depend on where you live and what kind of healthcare coverage you have. Talk to your healthcare providers to check the costs in your case. 

However, the NHS does not cover 3D or colour images, so if you want either of these services you can ask your healthcare provider what the expenses will be. Also, most medical centres will offer images of your ultrasound for £3 – £5.

What are doctors looking for in the anomaly scan?

The 20 week scan is much more than a photo op, however. It is a vital chance for your doctors to check that your little munchkin is growing and developing properly. The doctor will be able to look for many different developmental issues, such as:

  • Cleft lip/palate
  • Kidney function
  • Spinal development and skin covering
  • Chromosomal abnormalities
  • Brain problems and cranial malformations
  • Abdominal wall and skin covering organs/diaphragmatic hernia
  • Chambers and beating of the heart and the circulatory system
  • Stomach and digestive function
  • Small head or thigh circumference and leg and arm length
  • Blood vessels in the umbilical cord
  • Too much fluid in the brain

Just with this quick anomaly scan, your doctors can easily identify these and several other developmental issues or reasons for concern, with varying levels of accuracy. For example, there is over 88% accuracy for finding nervous system disorders, 84% for renal conditions, and about 40% for heart and blood circulation problems.

What if something is wrong? 

The majority of 20 week scans will turn up completely normal, with only 15% of women requiring a second scan or further testing. Of that 15%, a much smaller portion of women and foetuses will end up having an actual disorder or developmental problem.

In the case that the sonographer does find some item of concern, they will let you know at the moment. In most cases, you will have a second ultrasound with a specialist within 3 days of the first. They may also order other types of tests, such as a foetal echo scan if they suspect a heart problem.

In a worst-case scenario, in the 20 week scan your doctors may identify a condition that is dangerous or life-threatening to you or your growing baby. Depending on the condition, you may need to prepare yourself and your partner for difficult conversations and decisions, such as foetal surgery, surgery after birth, or even the need to terminate the pregnancy.

Finally, although it could lead you to make some serious decisions about your pregnancy, the 20 week scan is a very important step that you need to complete at the halfway point. Every expecting mum needs to go through it and very few of them discover any problems. So try not to be nervous and focus on the fact that with the 20 week scan you have a wonderful opportunity to see you little one for the second time, and possibly even learn if you’re expecting a boy or a girl. If you didn't have enough and want to see your baby again, you can also ask your doctor about the possibility of having a 4D scan!