When you’re expecting, you’ll have a lot of different tests at different times throughout your pregnancy to ensure you and your baby are healthy and developing properly. One of the most important testing benchmarks in your pregnancy is known as the 20-Week Anatomy Scan, or Anatomy Ultrasound. Here’s how it’s done and what it entails.
What Is the Anatomy Scan?
Around the 20-week mark of pregnancy, you’ll be scheduled for an ultrasound that will take a detailed look at baby to ensure they’re developing correctly. Your sonographer, or ultrasound technician, will do a thorough examination of baby, from counting their limbs all the way to examining their internal organs. At this point in pregnancy, baby is already so developed you’ll be able to see each of your little one’s tiny toes—and your sonographer might even be able to tell baby’s gender if you want! Pretty cool, huh?
Here are the basics of what your sonographer will measure and document during the ultrasound:
- Baby’s size: By taking measurements of certain bones and head circumference, your sonographer will be able to estimate baby’s height and weight. At this point your baby should be around 8 inches in length and weigh around 9 ounces.
- Face: Your sonographer will ensure baby’s facial features are formed properly, specifically their lips. The reason? They’re looking for cleft lip, a condition which causes an opening on one or both sides of the lips and requires special medical attention after birth.
- Brain: Baby’s brain and skull are measured and examined to see if baby has any rare conditions or cysts which could affect the brain or its development (it’s important to note that many fetal cysts disappear by the 28th week of pregnancy).
- Heart: Your technician will count baby’s heart chambers, check out the blood flow to and from the heart, and record their heart rate.
- Spine: Baby’s spine will be evaluated to ensure the vertebrae are properly aligned, and that baby’s skin covers the spine at the back.
- Kidneys and bladder: At this point both kidneys should be formed, and your sonographer will be able to tell if baby’s bladder is working properly.
- Limbs: Baby’s arms, legs, fingers and toes should be formed and countable.
Another thing they’ll check out? The position of your placenta and the blood flow through the umbilical cord. If your placenta is located low in your uterus, there may be concerns that it could cover all or part of the cervix (known as placenta previa), which can cause issues during delivery. Your provider will keep an eye on the position of your placenta as your baby and belly grow. Many times the placenta will move out of the way in time for delivery.
How Is the Anatomy Scan Done?
This ultrasound is typically done using an external transducer (or ultrasound wand) that uses high-frequency sound waves to generate a picture of baby and your uterus. Your sonographer will use a warm gel on your belly, and guide the wand around to look at baby and take measurements and photos. There’s also a chance your sonographer may use a transvaginal ultrasound wand to get a closer look at your cervix. If so, they’ll cover you with a sheet and with your permission, the wand will be inserted into the vagina. While both types of ultrasound wands can get a bit uncomfortable, neither will cause you any pain. If you need a break during your scan, just ask.
Since there are so many important things to look at and measurements to take, you should know that this isn’t always a quick appointment. Plan on at least 45 minutes to an hour of your time watching your little baby bounce around on the screen.
Another factor that can make your appointment longer or shorter? Your baby’s cooperation. If they’re positioned in a way that makes it difficult to see or measure, your technician might ask you to turn different ways, tilt your chair, or even ask you to get up and walk around to see if baby changes positions. If they are still unable to get the important measurements, they may ask you to come back for a follow-up appointment.
What Happens if There’s a Concern?
If your ultrasound shows anything that could be of potential concern, your doctor will order additional tests to have a more detailed look at baby’s development. Many times they’ll schedule more check-in ultrasounds as your pregnancy progresses, which means more chances to see your little one!
While it’s incredibly easy—and understandable—to feel alarmed if more tests are ordered, try your best to breathe, mama. Remember that sometimes baby is simply in a poor position to get a proper visual or measurement. Ultrasounds aren’t always the most reliable tool in making an exact diagnosis, but they’re a wonderful way to keep a close eye on your little one’s development and ensure they get proper care before and after delivery. You’re in good hands!