Ultrasound Scans

As soon as you find out that you are pregnant, you will need to make an appointment to see your GP. From here you will receive a schedule of antenatal appointments which will include routine ultrasound scans. As with all aspects of your antenatal care, you can choose to opt out of these scans; however they are very important in monitoring the health of you and your baby, so it would not be considered responsible to do so.

What is an ultrasound scan and how do they work?

Ultrasound scans are not just used during pregnancy. Sometimes referred to as sonograms, they are used to produce an image of the internal organs to allow doctors to diagnose and treat a range of conditions or illnesses. During pregnancy, ultrasound scans are used to produce images of the baby in the womb, and to highlight abnormalities or potential complications.

Most ultrasound scans during pregnancy are transabdominal, meaning across, or through the abdomen. However, occasionally during pregnancy you will be asked to have a transvaginal ultrasound - across or through the vagina. This is rare, but could be required if you have an ectopic pregnancy or if there are other perceived complications with your pregnancy.

The person who conducts these scans is called a sonographer. Transabdominal ultrasounds work by running a small handheld device, known as a transducer, backwards and forwards across your tummy. The device emits sound waves which are bounced back as an echo from the baby inside your womb, this enables the computer to produce a detailed image of your baby on a screen. The sonographer will lubricate your tummy first with a clear gel, so that the transducer can be moved around smoothly.

In the case of a transvaginal ultrasound, the process is similar but the transducer is placed into your vagina. A lubricating gel is used and the image is produced in the same way.

Hard tissues such as your baby's skeleton will show up white in the image because they show the largest echoes, soft tissues such as organs, muscle and flesh show up different shades of grey and finally fluids are seen as black on the image because the sound waves are able to pass through them.

What do they look for at ultrasound scans during pregnancy?

In the UK, all pregnant women have two routine ultrasound scans. The first of these is conducted between 8-14 weeks and is known as the dating and nuchal translucency scan. The sonographer will give you an estimated due date for your baby, based on the measurements of the foetus. They will also measure the nuchal translucency (fluid present at the back of the baby's neck), which will provide the risk factor of the baby having Down's syndrome. The nuchal translucency can only be performed between week 8 and 14 of pregnancy. If the sonographer finds that it is too early to do this test then you will be asked to attend another appointment at a later date. It is very important that you do not miss these appointments.

Provided that it isn't too early to tell, your first scan will also confirm the number of foetuses present. The closer you are to 12 weeks, the easier it will be for the sonographer to detect a multiple pregnancy.

The second routine antenatal scan is known as the anomaly scan. This scan must take place between 18 - 20 weeks plus 6 days. The main purpose of this scan is to ensure that the baby is the right size for this stage in pregnancy and to check for any structural abnormalities such as cleft lip, brain problems (these are rare) or heart defects. If any abnormalities are found then your sonographer will explain what needs to happen next. In addition, the sonographer will confirm whether your placenta is safely up and away from the opening of your cervix. If it is low-lying then you will be asked to attend another appointment at a later date to check whether it has moved out of the way.

Some hospitals offer you the chance to find out the sex of your baby at the second scan. Give yourself time to think about this in advance of the appointment so that you are sure whether or not you want to be told.

If you have any complications in your pregnancy then you might be asked to attend additional scans. At each of these scans the growth of your baby will be monitored, as will the specific area of concern that the antenatal team are monitoring.

Additional ultrasounds, 3-D photo and 4-D video scans are available privately and are becoming more popular. Do your research before choosing to purchase either of these.

Is it safe to have routine ultrasounds scans?

Ultrasound scans use sound waves, and not radiation, so they are considered to be harmless to both the mother and the baby.

What do I need to do to prepare for an ultrasound scan?

It is important that your routine scans take place at the right time during your pregnancy. For this reason you must not wait too long after finding out that you are pregnant before visiting your GP. He or she will then refer you to your local hospital or antenatal clinic for your dating and nuchal translucency scan. Your first scan must take place between week 8 and 14 of your pregnancy. Remember that from the date of your missed period you are already 4 weeks pregnant so you should make an appointment with your GP quite soon after this.

Once your appointment for the scan has been made, you should receive a letter of confirmation. This letter will also tell you what to bring to your scan. As with all antenatal appointments you should bring your maternity notes if you have been provided with them (you will get these from your midwife at your first appointment with them). For your dating and nuchal translucency scan you will be asked to arrive with a full bladder as this pushes the uterus up and enables a clearer image to be obtained. Your letter from the hospital should advise you on how much to drink. For later scans you will probably not be asked to have a full bladder, as it could actually restrict the view for the sonographer.

Going for scans can be emotional and quite worrying. Don't focus too much on the potential problems that scans can identify, look at them as a positive way of ensuring that your baby gets the best possible attention. Try to make sure that your partner can come with you so that they can share the experience. It can be quite magical to see your unborn child for the first time and often parents are taken by surprise with the emotion of it all!

Don't panic if your baby doesn't appear to be moving when you see them on the screen, remember that they spend a lot of their time asleep while they're lying snug in your uterus! The baby may need to move in order to give the sonographer a better view. If he or she needs encouraging then you may be asked to give a little cough and shake your hips from side to side in order to get them to change position.

Most hospitals now offer a photo of your scans. You will need to pay for these so make sure that you have some money with you as they make a wonderful keepsake for the future. It is also very exciting to be able to show them to your friends and family!