What is a Foetal Ultrasound Scan?
Simply put, a foetal ultrasound (or sonogram), is an imaging technique that uses soundwaves to produce images of your developing baby in the uterus. Typically, it will be used to evaluate how your baby is growing, and generally monitor your pregnancy. Your first ultrasound will usually be done during the first trimester to confirm the pregnancy and estimate how long you’ve been pregnant. This first test is very useful, as it confirms important information about your body and pregnancy that your health professionals can consider as your baby develops.
There are two main types of ultrasound examinations used:
- Transvaginal, where a wand-like device called a transducer is inserted into the vagina to send out soundwaves and gather the reflections. This type is used most often during early pregnancy, but may also be performed if a transabdominal ultrasound did not provide enough information.
- Transabdominal, where a traditional transducer is moved over your abdomen, reflecting images back onto a screen for your health professional to examine. Other variants of this type are available, including 3D ultrasounds that can be used to detect facial abnormalities, or Doppler ultrasounds which can measure changes in ultrasound waves and provide details on a baby’s blood flow.
What Are Ultrasound Scans Used For In Early Pregnancy?
Foetal ultrasounds in your first trimester are invaluable for giving your doctors foundational knowledge of both your baby and pregnancy, which they will then build upon as the pregnancy progresses. Your first sonograms will usually be used to evaluate the presence and size of the pregnancy, determine the number of foetuses, and estimate the gestational age of the foetus. It can also be used for early genetic screening, or to discover abnormalities within the uterus, cervix or foetus itself— which might be more difficult to resolve later in the pregnancy. Your health professional might use ultrasound in early pregnancy to:
- Confirm the location of the pregnancy. Some foetuses can develop outside the uterus, in the fallopian tubes. Known as an ectopic pregnancy, early ultrasound scans can help detect these pregnancies and resolve them before they cause any potential complications.
- Evaluate the growth of your baby. Ultrasound can be used to monitor your baby’s movements, breathing and heartrate. Doppler scans can ensure the baby’s blood flow is normal, and evaluation can determine if there are any suspected abnormalities.
- Identify birth defects. Early ultrasounds can help your doctor discover or screen for complications. 3D ultrasounds can determine if facial abnormalities are present by presenting three-dimensional data as a two-dimensional image. Echocardiography can provide detailed images of a baby’s heart, which can confirm or rule out congenital heart defects.
- Study the placenta and amniotic fluid levels. The placenta provides your baby with vital nutrients and oxygen-rich blood. Too much or too little amniotic fluid surrounding the baby in the uterus might require special attention, and an ultrasonic examination can help evaluate this.
- Investigate complications. If you’re experiencing excessive bleeding, or other complications of the uterus and cervix, an ultrasound might help determine the cause. Scans can pick up fibroids, pre-cancerous growths, and large clumps associated with deep infiltrating endometriosis.
If your healthcare provider doesn’t suggest an ultrasound, but you’d like the reassurance that one can provide, discuss this so you can work together to determine what’s best for you and your baby.