Each pregnancy ultrasound scan is pretty exciting (you get to see your baby) and slightly scary (just what will you see?), so it’s a good job to get prepared.
Chances are you’ve squinted at a friend’s grainy ultrasound picture, nodded and wondered just exactly what you were looking at. Now it’s your turn for the scans and excitement.
How do ultrasounds work?
You get what ultrasounds do, but how do they work? Impress your partner by understanding the lingo.
Firstly, the device the sonographer holds against your bump is called a transducer.
This sends high frequency sound waves in your abdomen, where your baby’s tucked away. These waves bounce off your baby and back to the computer to be translated into a picture, that’s what comes out as the white area.
‘You could be given extra scans in your pregnancy if particular issues are a concern,’ says Dean Meredith who is a sonographer at The Portland Hospital, London. ‘Growth issues such as growth restriction or large for dates would warrant extra scans or issues such as diabetes, if you are pregnant with multiples, any fetal anomalies or an unusual placental position are detected.’
These are sometimes offered between six and 11 weeks if you have a history of miscarriage, if you are experiencing bleeding or pain, or if you've had fertility treatment.
The sonographer may use a special scanning probe, which is placed in your vagina, as ordinary equipment may not be able to detect your baby yet.
Dating or 12-week scan
This is offered to help doctors accurately date your pregnancy and is done between 11 and 16 weeks. You will probably have a 'pelvic' ultrasound, where the transducer is placed on the skin over your pelvis.
Done between 10 and 13 weeks, this scan tells you your risk of having a baby with Down's syndrome by measuring the size of the groove at the back of your baby's neck often done in conjunction with the dating scan. Your doctor will use the scan measurement, your age and a blood test to calculate your risk.
Offered to most women around 19-20 weeks, this is a detailed scan that makes sure your baby is developing properly and pick up any problems or abnormalities.
After 20 weeks
You may be offered extra scans if you have a complication, such as placenta previa. If there’s a family history of birth defects, such as heart defects, you may also have later checks, as you will if you are expecting twins or triplets.
The benefits of 3D and 4D scans
Both 3D and 4D scans are considered just as safe as a 2D scan, because the image is made up of sections of two-dimensional images converted into a picture.
However, the benefits of having more scans just for the fun of having another glimpse at your baby isn’t clear. With 3D and 4D scans, you have the benefit of seeing your baby's skin covering her internal organs. You may also get to see the shape of your baby’s mouth and nose, or see her yawn or stick her tongue out.
‘3D/4D scanning allows us to see the baby in a format that we are used to seeing such as in a photo or film,’ says Dean.
‘2D is essentially taking a slice through the mother and baby that is only a few millimetres thick and is useful to see the internal structures of the baby.3D/4D only really works if the baby is in a good position and is an excellent way of looking at the facial structures giving an insight into how baby may look once she’s born.’
Ask at your hospital to see what’s available to you.