An ultrasound scan sends sound waves through to your uterus, these waves then bounce off your baby as echoes. These echoes are then turned into an image on a screen which shows in detail your baby, his movements and position. Clever hey!
On the screen you will see white areas, which are hard tissues such as bone, grey area which are soft tissues and black areas which is the amniotic fluid surround your baby. The person who is performing your scan, known as the sonographer will interpret all this information when looking at your baby.
The first scan at roughly 11-13 weeks is always going to be the most exciting, this will be the first time you get to see your baby! The sonographer will most likely print your first image of your baby, it can take pride of place on the fridge for the next 9 months! The purpose of this first scan is to check how many babies your are carrying (congratulations if it’s twins!) and to check that your baby is developing normally. You will also be given your expected due date. The sonographer will also look to check that your baby’s heart if beating and at the basic anatomy of your baby. Unfortunately this first scan won’t be able to tell you the sex of your baby.
During the second trimester of your pregnancy you will be offered an anomaly scan. This will happen at approximately 20 weeks. The purpose of this scan is to take a more detailed look at your baby to ensure he or she is developing correctly. The anomaly scan sometimes need to be repeated a few weeks later, particularly if your baby isn’t behaving himself! This can happen if your baby is in an awkward position. If you are keen to find out the gender of your baby, the sonographer will usually be able to tell you at this scan.
During the third trimester, your midwife or consultant may request a further scan. This can happen if you previously had a low birth weight baby, are expecting twins, have complications such as high blood pressure or diabetes, are expecting a baby which measures smaller than expected or are measuring larger than expected.
An abdominal ultrasound scan is generally painless. It can be a little uncomfortable when the transducer is pressing on your tummy, this is usually because you have a full bladder. This is requested before ultrasound scans to assist the sonographer to see your baby better. If you are in pain, tell your sonographer. She may allow you to empty your bladder a little to ensure you are more comfortable. Luckily by the time you get to the third trimester the need for a full bladder is not necessary as your baby is much bigger.
It’s natural of course to worry that you ultrasound scan will show a problem. Sometimes a clear diagnosis can be seen on scan, such as with spina bifida, or the scan may show minor changes which need investigating, but are often nothing to worry about. If your sonographer finds something unusual during your scan she will refer you to a consultant within 24 hours and possibly onto a fetal medicine specialist. Once your have been referred, the consultant may carry our additional tests to give you a definitive answer.
Some people have expressed concerns over the safety of ultrasound scans. Be reassured that ultrasound scans have been used throughout pregnancy for a great many years and to date nobody has found them to be harmful. There are specific guidelines the sonographer has to follow and there have been no research linking ultrasound to such things as low birth weight, childhood cancers, dyslexia or hearing conditions. However, ultrasounds should only be performed when necessary.
For further support contact the charity Antenatal Results and Choices (ARC).