Ultrasound scans use sound waves to create a picture of your baby on a TV screen. The scans are safe and can be carried out at any stage of your pregnancy.
Most ultrasounds are 'transabdominal ultrasounds'. This means that the ultrasound probe is rubbed gently on your tummy (abdomen) to produce a picture of the baby on the screen.
Transvaginal ultrasound scan
If you are in early pregnancy (6 to 12 weeks) you may need to have a 'transvaginal ultrasound scan'. This means that the ultrasound probe is placed gently inside your vagina.
This scan is safe for your baby. It can be the best way to get a clear view of your baby’s heartbeat in the first trimester, especially between 6 to 12 weeks.
What happens during a scan
Ultrasounds are usually performed by specially trained sonographers or radiographers. They normally take about 20 to 30 minutes.
You will be brought into a darkened room. The darkness makes it easier for the person doing the scan to clearly see the picture on the screen.
You will be asked to lie on a couch and lift up your top to show your tummy. You may need to roll down the waistband of your trousers. The person doing the scan may tuck some tissue paper into your waistband. This is to protect your clothes from the ultrasound gel.
Next, they will put the ultrasound gel onto your tummy. The gel helps the probe to move. As the probe moves over your tummy, an image will appear on the screen. The pictures you see are in black and white.
You may see an outline of your baby. You may not be able to tell where your baby is in the image. It is normal for the pictures to look a little cloudy or blurry at first. The person doing the scan will often point things out to you like the baby’s heartbeat and head.
The scan does not hurt. But the probe may need to be pressed quite firmly on your tummy. This can be uncomfortable if your bladder is full.
Types of scans
The two most common pregnancy scans offered are:
- dating scans - usually before 15 weeks, this checks details such as your baby's weight and expected date of birth
- fetal anatomy scans - usually at 18 to 22 weeks, this checks how your baby is developing in the womb, including any possible birth defects
Most ultrasound departments will allow you to bring a support person with you for your scan. Check this with your maternity unit. Children are usually not allowed.
Extra scans during pregnancy
Extra scans are only done when there is a medical reason. Most pregnant women will probably only have 1 or 2 scans.
If a possible problem is found
If a scan shows a possible problem, you may need to have extra scans and more tests. If you're offered more tests, you will be given information about them. This will help you decide whether or not to have them. You can discuss this with your midwife or consultant.
Your obstetrician may also refer you to a more specialised obstetrician. You might need to meet this obstetrician in a different maternity hospital.
If your scan shows a possible problem, the time, place and type of birth may need to be carefully planned. This is to make sure you and your baby are kept as safe as possible.
It can be upsetting when your scan suggests that there is a problem with your pregnancy or your baby. Your midwife, obstetrician and GP are there to support you. Ask them to explain everything to you in detail.
Reasons for extra scans
You may need extra scans if:
- you have bleeding
- you have worries about your baby's movements
- your baby's growth needs to be monitored
Extra scans may also be needed to check:
- the position your baby is lying in
- the position of the placenta (afterbirth)
- the amount of amniotic fluid around your baby
Most maternity hospitals do not routinely do scans to determine the sex of your baby.
Private ultrasound scans
You may choose to pay for extra scans during your pregnancy.
You may do this because you want:
- to have your scan earlier in your pregnancy
- more reassurance - for example, if you had a previous pregnancy loss
- to find out the sex of your baby
- a 3D or a 4D scan – these may give a better view and show your baby's face in more detail
- more photos of your baby or a video recording
There are no known risks to you or your baby from having extra scans.
Extra scans may not give you much more information than your regular scans. They can be expensive and you will need to book the scan yourself.
Your GP, midwife or obstetrician will tell you where you can get private pregnancy scans in your area.
If a concern is found on a private scan, follow-on services may not be available there. You will need to contact your maternity hospital. Make sure you have a copy of the scan report.