Anticipation is a big part of pregnancy. You wonder what your baby will look like, and more important, whether he or she will be healthy. An ultrasound offers an early peek inside the womb, and a chance to learn a bit more about your baby’s expected due date and well-being.
A first-trimester ultrasound is usually done 7 to 8 weeks from the first day of your last menstrual period, says Rebecca Jackson, MD, assistant professor of obstetrics and gynecology at the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, PA. “The main thing is to confirm pregnancy dating to make sure we have an accurate due date, to make sure that we’re able to see the baby’s heartbeat, and to see if there’s one, or more than one, fetus.”
Your doctor can also use this test to screen for genetic problems, as well as to find any issues with your uterus or cervix. If you’re anxious to learn the baby’s sex, you’ll have to wait a bit longer. The gender reveal, as well as more info about your baby’s anatomy, will come at your next ultrasound, which happens between weeks 18 and 22 of your pregnancy.
The typical ultrasound creates a two-dimensional cross-sectional image of your baby. Some facilities advertise 3D and even 4D ultrasounds, which produce a more photograph-like image of your baby. These high-tech scans aren’t necessary, but they may be preferable if you suspect your baby has an abnormality like a cleft palate that’s harder to see clearly with 2D imaging.
A prenatal ultrasound can be done in one of two ways — transabdominally (over your belly) or transvaginally (into your vagina). You may get a transvaginal ultrasound if it’s very early in your pregnancy, because it produces a more accurate image of your still tiny baby.
For a transabdominal ultrasound, you’ll come in with a full bladder. A full bladder tilts your uterus up and moves your intestines out of the way for easier viewing.
The technician will put some gel on a handheld device called a transducer and move it across your belly. The transducer releases sound waves, which bounce off the fetus’s bones, fluids, and tissues to create an image of the baby in your womb. You’ll be able to see your baby on a video screen.
During a transvaginal ultrasound, you’ll undress from the waist down and put your feet up in stirrups, just like you would for a pelvic exam. The technician will cover the transducer with a condom-like sheath and lubricant before placing it inside your vagina.
Having an ultrasound during your pregnancy is important, because it can give your doctor a lot of information about your baby quickly. “It’s very safe in pregnancy,” Jackson says. “There’s no risk.” If the technician discovers any problems, you may need to come back for a second ultrasound or other tests.
By the Numbers
1958: The year doctors performed the first ultrasound.
2: Number of ultrasounds, on average, women in the United States get during the course of their pregnancies.
120 to 160 beats per minute: A normal fetal heart rate.
75%: How accurate ultrasound is at determining the baby’s sex in the first trimester.
100%: How accurate ultrasound is at determining the baby’s sex in the second trimester.
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