Many pregnant women have at least one scan throughout their pregnancy. Some women don’t like the practice while some are indifferent to it. Many doctors recommend ultrasounds to their patients during pregnancy but only with a valid medical reason.
An ultrasound scan is a procedure where a device (transducer) passes sound waves through your uterus. These waves then bounce off the baby just like an echo would and the echoes are converted into an image showing the baby’s movements and position. Bones will appear white because they make the biggest sound waves since they are hard tissues. Soft tissues look grey and fluids black. These different shades are what the sonographer uses to interpret the image.
A first scan can be an emotional and exciting experience since you get to see what your baby looks like in there. Some ask to print the image and have it as a keepsake. If you are interested in taking this image home with you make sure you let the sonographer know at the beginning of the scan. Also find out if you’ll need to pay extra for it because some hospitals charge for this service.
What ultrasounds are for
The purpose of an ultrasound depends on the stage of pregnancy you are in. It can be used to:
- Find out whether you are having one baby or multiple
- Check the baby’s heartbeat
- Detect an ectopic pregnancy. This is when an embryo implants in the fallopian tube instead of the womb.
- Find out the actual age of the fetus. This is done by measuring the baby.
- Determine the amount of amniotic fluid you have and the position of the placenta
- Examine the baby and find out whether all organs are developing properly
- Find out the cause of any bleeding
- Find out why a blood screening test gave abnormal results
- Evaluate your baby’s risk of Down’s syndrome. This is done using the nuchal translucency scan by measuring the amount of spinal fluid at the back of the baby’s neck. It is done at 11 weeks plus two days to 14 weeks plus one day.
- Diagnose any abnormalities such as spina bifida
- Show you the sex of the child. This may however be dependent on the position of the baby.
When are they done?
Your first scan should ideally be a dating scan between 11 and 13 weeks plus six days. It will confirm your due date. This test is very important if you will be doing tests for Down’s syndrome because the dates have to be accurate for accurate results. You can however have an early scan at around six or seven weeks if you are experiencing any problems, like vaginal bleeding.
The nuchal translucency (NT) scan (for Down’s syndrome) comes between 11 weeks and two days and 14 weeks plus one day. Alternatively, it is done when the baby is between 45mm and 84mm.
You may be asked to do an anomaly scan at 20 weeks to check the baby’s development. If the sonographer doesn’t find all that they are looking for it can be repeated at 23 weeks.
The doctor may recommend that you get a growth scan between 28 and 40 weeks if you are having twins, previously had a small baby, measuring larger than expected, measuring less than expected or have any other complications.
How are they done?
The sonographer puts some gel on your tummy and moves a hand-held device, known as a transducer, over your tummy. The waves from this device create the images. You may need to have a full bladder if in early pregnancy so as to help the ultrasound waves get to the womb.
In the event that you are overweight or the baby is deep in your pelvis, the sonographer will have to slide the transducer into your vagina to get a better picture of the baby. They will still use a gel to help it slide in and it will be covered with something like a condom so don’t worry about infections.
Generally, ultrasounds are considered safe. There haven’t been any findings of negative effects if they are carried out correctly. That is why medical experts recommend that they be carried out by trained professionals and only for clear medical reasons. You don’t really need to have one though so relax!