Pregnancy Scans and 3D/4D Ultrasounds

If you’re expecting a baby, you will probably have an ultrasound in your first semester - this helps your doctor or midwife have an idea of your estimated due date. You will probably have another ultrasound around 20 weeks of pregnancy called the anatomical scan. In this second ultrasound your caregiver will be checking that your baby’s organs are developing normally as they should be.

Sometimes doctors and midwives will request a third ultrasound closer to the end of your pregnancy, if there are any concerns regarding your baby’s growth, position (such as breech) or the health of your placenta. If you are high risk or pregnant with twins, additional scans may be recommended. Part 2 of this blog will discuss the accuracy of ultrasounds for estimating due dates and size of your baby.

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Potential Concerns with Ultrasounds

Even though the appropriate use of ultrasound is deemed to be safe during pregnancy, experts like Shazam Vaezy, Ph.D., an FDA biomedical engineer have concerns regarding over-exposure: "Although there is a lack of evidence of any harm due to ultrasound imaging, prudent use of these devices by trained health care providers is important. Ultrasound can heat tissues slightly, and in some cases, it can also produce very small bubbles (cavitation) in some tissues."  (1)

Since the long-term effects of tissue heating and cavitation are not known, the FDA in the U.S. therefore recommends that prenatal ultrasound scans be performed only when there is a medical need.

3D/4D Ultrasounds

3D/4D ultrasounds are not standard prenatal tests. A 3D ultrasound creates a three-dimensional image of your baby, while 4D ultrasounds create a live video so you can watch your baby smile or yawn.

A 3D ultrasound may be occasionally recommended by your OB if there is a particular area of concern. In some cases 3D scans allow doctors to detect a problem which can be addressed while baby is still in the womb. However, the most frequent reason pregnant couples go for a 3D scan is to bond with their baby. This can be especially cool for dads and help them feel more connected during the pregnancy!

While ultrasounds are safe, too much exposure may not be good for your baby. In some private clinics your baby may be exposed for up to an hour in order to get a good video. This has raised controversy over the increasing number of pregnant parents who opt for keepsake videos.

Health Canada Warnings

The Society of Obstetricians and Gynaecologists of Canada (SOGC) and the Canadian Association of Radiologists (CAR) have issued a warning against "entertainment" ultrasounds in a joint policy statement issued in 2014: “The CAR and SOGC strongly oppose the non-medical use of fetal ultrasound and encourage governments to join with our organizations to find appropriate means to deal with this public health issue…Both Health Canada and the Food and Drug Administration (FDA) in the U.S. have recommended against commercial and entertainment ultrasound. Health Canada recommends that ultrasound should not be used to take a picture of the fetus solely for non-medical reasons.. or to learn the sex of the fetus solely for non-medical reasons...The fetus should not be exposed to ultrasound for commercial and entertainment purposes, and it could be considered unethical to perform these scans​.” (2)

Additional Considerations

The potential for false-positive diagnoses is also a major concern, according to the SOGC. It can lead to unnecessary investigations and incredible anxiety for pregnant couples. Some parents, having experienced a scare during their previous pregnancy as a result of a scan, opt out of standard prenatal ultrasound tests altogether during subsequent pregnancies. This is more likely for parents who have decided that they will not terminate a pregnancy irrespective of any medical condition their baby may have.

Ultimately, parents today want to be informed and it is a good idea to do your research and discuss with your OB or midwife. Part 2 of this Blog will discuss the accuracy of ultrasounds for estimating your due date and for evaluating baby’s size.

Source:
1.      http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm095508.htm
2.      http://www.car.ca/uploads/About/JOINT_CAR-SOGC_Stmt_Non-Med-Use_Fetal_US_EN_20140220.pdf