What to Expect at Your 20-Week Ultrasound

I was so excited for my 20-week ultrasound. I hadn’t seen the baby growing in my belly since my 12-week scan, and I knew this would probably be my last chance to have a look at the little bean before D-day. But, here’s the thing: There’s a lot more to it than determining your baby’s gender. “The 20-week ultrasound is one of the most important doctor’s visits of the entire pregnancy,” says Anna Barbieri, MD, an ob-gyn in private practice in New York City. “It checks for the correct development of all of your baby’s organs, and it will significantly reduce the chance that your baby would be born with a major birth defect.” With all that in mind, here’s your chance to read up and go into your 20-week scan prepared.

What is the 20-week ultrasound for?

This ultrasound (also known as the anatomy scan) is done to check out the structure of your baby’s organs (think the brain, spine, heart, stomach, and kidneys), in order to make sure everything is developing normally and there are no abnormalities, says Melissa Goist, MD, an ob-gyn at The Ohio State University Wexner Medical Center, in Columbus, Ohio. She’ll check your baby’s fingers and toes, too, and count and measure the bones to make sure that your baby’s growth is on track. Additionally, she’ll check on the location of the placenta to make sure that you don’t have placenta previa, a condition that occurs when the placenta covers the cervix. “It can result in certain complications, like bleeding, and requires earlier delivery by C-Section,” says Dr. Barbieri. 

Will I definitely find out my baby’s sex?

Your baby’s genitals are well formed at this point, so as long as he or she cooperates the technician should be able to determine whether you’re having a boy or a girl. However, science and technology have come a long way and Dr. Barbieri notes that most people are able to find out their baby’s gender by blood work as early as 11 weeks and by ultrasound at 16 weeks. 

What if the ultrasound shows a problem?

If your doctor sees an abnormality, she’ll most likely schedule more tests. Dr. Barbieri says that it really depends on what the abnormality is to determine the appropriate test. “For example, a structural heart abnormality may require additional testing with a fetal echocardiogram [a specialized cardiac ultrasound],” she explains. “Some abnormalities suggest the presence of a genetic syndrome, such as Downs, or an infection like CMV, which can then be hopefully ruled out with an amniocentesis.”

Before you start stressing out, though, remember that the 20-week ultrasound is usually a very happy occasion. You get to see your baby! 

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