20 Week Ultrasound – What to Expect
The 20 Week Ultrasound, a.k.a. the ’20-week anatomy scan’, is a sonogram in mid-pregnancy to confirm that your baby is growing normally. Ultrasound technicians find and measure the baby’s internal organs, baby’s growth and check for spina bifida or anencephaly. The tech will also check to see if there is sufficient amniotic fluid.
After you leave, a specialist will look at the scan and let you know if they find any possible problems.
Some parents-to-be would rather know ahead of time if their baby has any chromosomal abnormalities. The most common reason people want to get an ultrasound is finding out the sex of the baby.
Is the 20 Week Ultrasound (Anatomy Scan) Safe?
Some pregnant women choose not to have an ultrasound at all. Unless one is medically indicated (for example, you’re measuring small), they figure the possible risks outweigh the benefits.
Ultrasound technology and the effect it has on a growing fetus is not well understood. We know that the ultrasound waves cause cavitation (pitting) in cells and that babies are generally bothered by the procedure.
Ultrasound technicians often have trouble getting a good image because of the baby’s position, or the baby is moving away or putting his/her hands in front of his/her face.
The American Congress of Obstetricians and Gynecologists (ACOG) states that:
Currently, there is no reliable evidence that ultrasound is harmful to a developing fetus. No links have been found between ultrasound and birth defects, childhood cancer, or developmental problems later in life. However, it is possible that effects could be identified in the future. For this reason, it is recommended that ultrasound exams be performed only for medical reasons by qualified health care providers.
The FDA recommends against extra “keepsake” (3-D or 4-D) ultrasound photos or home doppler use, saying:
The long-term effects of tissue heating and cavitation are not known. Therefore, ultrasound scans should be done only when there is a medical need, based on a prescription, and performed by appropriately-trained operators.
What Will The 20-week Ultrasound Show?
Most of the images on the screen are relatively difficult to interpret for the untrained eye. It can look like a lot of grey, white and greyer smudges.
The technician is looking for organs and outlines; the technician can point things out to you if you ask.
Most of the time, you can find out the baby’s gender. Sometimes they will alter your due date based on the 20-week scan, but dating is notoriously unreliable this late in pregnancy. It’s also difficult to tell where the cord is during pregnancy on a scan, but sometimes they will check and tell you.
You may certainly be able to see the baby’s head and profile and may be able to see the baby’s fingers and toes.
What Should I Wear?
Wear pants or a skirt that you can easily unbutton and pull down and a shirt you can easily lift up.
Typically you keep all your clothes on, but expose the belly, down closer to your pubic bone. Especially if you get another sonogram later in pregnancy, they may need to do the imaging lower.
Why Isn’t the Technician Talking to Me?
The technician’s job can be tricky, especially if your little one is moving a lot. You don’t want to be under the wand forever, so he/she may also be trying to work quickly.
Ultrasound techs are people, too, so if you got a quiet one, you may have to ask to be more involved. It’s not his/her job to interpret the findings.
The technician is not supposed to tell you that everything is fine or that there are problems because he/she’s not trained to determine that. Even so, a friendly one will chat with you and point out the baby’s body parts.
Can I See the Screen?
While the tech is taking measurements, she may need to face the screen away from you for some time. You can definitely ask to see what they see and get the screen turned toward you at intervals.
The images are hard for most of us to interpret, but a good and kind tech will point things out. If not, you should just ask. “What’s that line of little white spots?” (Probably the spine) or “where’s the baby’s hands?” If you want to see, just ask.
When Can I Find Out My Baby’s Sex?
Most of the time, the technician can find the baby’s genitals and tell you if it’s a boy or girl. He/she’s looking for three lines to indicate a baby girl and little appendage for a baby boy.
The umbilical cord can look like a penis, and especially if baby is moving a lot, it’s not always perfect, even in these modern times. People do sometimes get a surprise on birth day.
How Does it Work?
High-frequency sound waves that bounce off the baby and your other insides get pieced together to form an image on the screen. You lay down and expose your belly.
The technician puts some cold gel on the transducer (wand) and then moves it slowly but almost constantly around your belly.
The baby feels the ultrasound waves and doesn’t like them, so don’t be surprised if it’s hard to get the right angle or see what you want to see because baby is moving or putting his/her hands in the way.
How Should I Prepare for the 20 Week Pregnancy Ultrasound?
There’s not much you need to do. Wear comfy clothes. Sometimes it helps if you have a full bladder because it raises baby more fully out of your pelvis to simplify imaging.
Disclaimer: Pregnancy by Design’s information is not a substitute for professional medical advice or treatment. Always ask your health care provider about any concerns you may have.
American College of Obstetricians and Gynecologists (2017). Ultrasound Exams. Retrieved from https://www.acog.org/Patients/FAQs/Ultrasound-Exams.
Food and Drug Administration. (2014). Avoid Fetal “Keepsake” Images, Heartbeat Monitors. Retrieved from https://www.fda.gov/consumers/consumer-updates/avoid-fetal-keepsake-images-heartbeat-monitors.
Free Video Guide on Creating Your Birth Plan! The Complete Guide to Writing Your Birth Plan is a step by step walk-through of the most important aspects of creating an effective birth plan. The guide covers everything you need to know from interviewing a provider, comfort measures and additional 1-page birth plan to talk over with your provider. Get free access today!