As long as your pregnancy is not a high-risk one, you will only have about four ultrasound scans in the nine months. If there are risks to either you or your baby, your doctor will order more ultrasound scans done. This is to help him see what goes on in your uterus as it is hidden from plain sight.
Your First Ultrasound Scan
A first scan can be very exciting because it gives you a first glimpse of your baby. Your sonographer may even print out the image of your baby and give it to you as a keepsake. However, you will need to ask at the start of your scan, and your hospital may charge for this service.
Some private ultrasound clinics will allow you to print a copy of your baby. It's great to have that first photo to keep and share. But the purpose of the scan is to check how many babies you're carrying, and whether they're developing normally. Your first scan won't be able to tell you the sex of your baby just yet. A first-trimester scan will only check that your baby's heart is beating. It will also look at the basic anatomy of your baby’s head, abdominal wall, and limbs.
When Are Ultrasound Scans Usually Carried out?
During your first trimester, you may have an early scan at about six weeks or seven weeks. However, your doctor will only offer you an early scan if you're experiencing problems, like pain or vaginal bleeding.
Your first scan is more likely to be a dating scan when you're between about 10 weeks and 14 weeks pregnant. This will confirm your due date and check whether you are having twins. The dating scan is especially important if you're having screening tests for Down's syndrome. This is because you need a correct due date to make the result accurate.
You can have a nuchal translucency (NT) scan for Down's syndrome between 11 weeks and 14 weeks of your pregnancy. Or when your baby measures between 45mm (1.8in) and 84mm (3.3in). In most cases, this is combined with a blood test for increased accuracy.
Your Second Trimester Ultrasound Scan
In your second trimester your doctor will offer an anomaly scan between 18 weeks and 21 weeks. This is to check that your baby is developing normally. If the anomaly scan shows that your placenta is lying low in your womb, you may need a follow-up scan at 32 weeks.
Most of the time, the placenta has moved into a better position by the time you're 32 weeks pregnant. However, if your sonographer can't get a clear picture, she may offer you a transvaginal scan to confirm the position of your placenta.
Your Third Trimester Ultrasound Scan
In your third trimester, your doctor or midwife may recommend that you have a growth scan between 28 weeks and 40 weeks. This will be if you:
- previously gave birth to a small baby
- are having twins
- have other complications, such as diabetes or high blood pressure
- are pregnant with a baby who measures smaller than expected
- are unexpectedly bigger and your midwife suspects that there's too much fluid around your baby
Resource: Web MD
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