What are scans actually for?

The first scan you have in pregnancy is an exciting moment for every parent to be. Until now, it’s often difficult to even believe that you are pregnant.. peeing on a stick just doesn’t seem like proof enough! And without a bump or feeling them wriggling inside, a small part of us wonders if we’re just imagining the whole thing!

But, scans in pregnancy aren’t ACTUALLY for us to just take a quick peep, find out the gender and take home a photograph. So, what are they for?

12 Week Scan

For most women, your first scan, - known as the ‘dating’ scan, the ‘nuchal scan’ or the ’12 week scan’, will take place somewhere between 11-13+6 weeks of pregnancy (as estimated by your last period). The sonographer looks for several things during this scan, and as with anything in pregnancy and birth- each part of this is optional (as is having scans at all!).

·        Anatomy- the sonographer will check for a beating heart, and check the developing anatomy of the baby at this stage (the umbilical cord, skull and brain, arms, legs, hands and feet, some of abdominal organs such as the stomach).

·        Dating- the sonographer will take measurements of baby to give a more accurate estimated due date. A due date by scan is more accurate than dating by your last period, though still not necessarily a completely reliable method of knowing when your baby will be born! (More on due dates here.)

·        Checking how many babies are in there! If you’re expecting twins, this will be when you find out!

·        Check the position of the placenta- your placenta can ‘implant’ to anywhere in your uterus! Knowing where it is can be helpful in knowing what to expect during the rest of pregnancy. An anterior placenta (at the front) might mean that you feel less movements overall or that you feel movements a little later in pregnancy. (Any concerns with movements please speak to your midwife asap). If your placenta is low down, they might like to keep an eye on it at future scan to check it has moved upwards as the uterus grows.

·        All pregnant women will be offered a Nuchal Translucency screening as part of this scan. As the fetus develops, it will have a sac of fluid at the back of his/her neck. In babies with down’s syndrome, the level of fluid is higher. Your sonographer will measure the level of fluid, and combined with the results of a blood test and other factors such as your age, they are able to estimate the likelihood of your baby having down’s syndrome, Edward’s Syndrome or Patau’s Syndrome (More on those here). This is a screening test, not a diagnostic test- so result may look something like ‘1/1000’ chance. A chance of 1/150 or less would be considered ‘high’. As with anything in pregnancy and birth, this is an optional part of the scan, and entirely up to you as to whether you opt for it or not.

20 Week Scan

In the UK your next scan will be between 18-21 weeks, sometimes known as the ‘anomaly scan’ sometimes known as the ’20 week scan’. So what’s this one for?

·        The main purpose of this scan is to check baby’s development. The sonographer will look in detail at baby’s organs, and take measurements to check they are developing as expected and growing well and proportionately. (You can find out what they look for specifically here). If this scan identifies any suspected problems, you will be told straight away, and referred to a specialists usually within 3-5 days.

·        They will check the blood flow in the placenta and umbilical cord, as well as the position of the placenta- which your midwife will need to know before birth.

·        The fluid levels around baby will also be checked, to see that there is enough for them to move around freely.  

·        Then of course, if you want to know, they may be able to tell the sex of the baby at this scan!

You may be offered other scans throughout your pregnancy for a variety of reasons too. But yes, scans are super exciting and a lovely moment to connect with your baby, but they share with us very important information too!