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Ultrasounds and Sonograms

Congratulations on your pregnancy. It's an exciting time that can also be fraught with anxiety.

One key way to put your mind at ease and keep both you and your baby safe is to have regular checkups. Ultrasounds can help detect any possible complications early on, and are also a special first glimpse at your unborn child.

Unlike x-ray imaging, ultrasound scanning does not use ionizing radiation and has an excellent safety record, making it suitable for fetal scans.1 The sound waves used during an ultrasound scan cannot be heard and the power is very low.

They are conducted by a doctor or ultrasound specialist who checks the health of the baby, uterus, and placenta.2

90% of pregnant women in most of the developing world have at least 1 ultrasound during their pregnancy.3

It is advisable to have several scans over the course of your pregnancy to check on the baby's progress and monitor the well-being of both mother and baby.

Below is a description of each of the scans and what the ultrasound specialist or doctor will be monitoring.

1st scan

  • Approximately 6-10 weeks. The first signs of pregnancy can be seen as early as 5 weeks.
  • Confirms that the pregnancy is viable.
  • Checks for a heartbeat.
  • Checks for twins or multiple births.
  • Rules out any internal bleeding.
  • From 8 weeks onward, you should be able to confirm your due date through your scan. This is known as a “dating scan.”

2nd scan

  • Also known as the “nuchal translucency (NT) scan.”
  • Approximately 11-13 weeks.
  • Checks the early structural development of the fetus
  • Neck thickness can show indications of a chromosomal abnormality, although it cannot give you a definitive answer.
  • Checks the health of the umbilical cord.

3rd scan

  • Approximately 18-20 weeks.
  • Also known as the “morphology scan.”
  • This is considered the most important scan, as your baby is developing vital organs such as its heart, lungs, and kidneys.
  • Rules out physical defects.
  • Around 3% of all fetuses have a major birth defect.4
  • If a defect is detected, your doctor will inform you of the possible implications for you and the baby, as well as create a plan going forward to check more regularly on the baby's development.
  • The cervix is also inspected to see if the mother is at an increased risk of early labor. If so, you can talk to your doctor about what provisions can be taken to try to keep the pregnancy as close to full term as possible.

4th scan

  • 32 weeks.
  • This is the “growth scan.”
  • Some obstetricians and gynecologists don't consider this scan compulsory unless a birth defect has been detected.
  • At this scan, the ultrasound specialist or doctor will check to see that the baby is growing normally and at the rate expected.
  • They also check that there is enough fluid around the baby and that the right volume of blood is passing to the baby.

These are the four main baby sonograms you might expect during your pregnancy. Most women with healthy pregnancies have two scans, a dating scan and a morphology scan.5

If your pregnancy has been diagnosed as complicated/high-risk, or if you are expecting multiple births, then you will be given specific advice and may need to come in for more private ultrasounds.

Here at BronxDocs

We know what a special and scary time expecting a baby can be. Ultrasounds are particularly exciting and daunting for expectant parents. It's the first time you see your baby, the first time you hear their heartbeat, and the first time you watch them move. These are moments to treasure, but there's always a possibility, however small, that you may run into complications. We want to celebrate the excitement with you, and handle any unwanted news with care and sensitivity.

3D ultrasound scans

At BronxDocs, we have 3D and 4D sonogram technology. We know you're impatient to see and get to know your little one. Ultrasounds have developed astoundingly within the past 20 years. The level of detail available to expectant parents now would have been unthinkable a generation ago. In a 3D ultrasound, you can already see the baby's features and make a guess at whose nose they inherited! A 4d sonogram captures the baby's movements.

While they are available from about 16 weeks, 3D ultrasounds also aren't a perfect technology. If there isn't a lot of fluid around the baby the images can look a little strange. But don't worry. It's just a technical issue and generally not an indication of a defect in your baby. The best time to get a pretty image is from about 24 weeks.

While ultrasounds are safe and painless, the FDA recommends limiting ultrasounds to medical purposes. So, if you want a 3D or 4D image, mention it before your next scan to see if the two can coincide.


1. FDA. “Ultrasound Imaging.” (2019) Retrieved from: Oct. 2019.

2. FDA. “Ultrasound Imaging.” (2019)

3. Women's and Children's Health Network. “Pregnancy: Ultrasound scan during pregnancy.” (Aug. 2018) Retrieved from: Oct. 2019.

4. CDC. “Data & Statistics on Birth Defects” Retrieved from: Oct. 2019.

5. What to Expect Editors: “Ultrasound During Pregnancy” (2019) Retrieved from: Oct. 2019.

Additional Sources:

Pregnancy Birth and Baby. “Ultrasound Scans.” (Feb 2018) Retrieved from: Oct. 2019.