Depending on your doctor, expect to have your first ultrasound sometime between 6 and 12 weeks, says Santa Monica–based ob-gyn Sheryl Ross, MD. Baby grows quickly and will look very different in just a few short weeks, so don’t panic if you don’t see as much detail at an earlier ultrasound (the below image is about 12 weeks). The first ultrasound dates and confirms the pregnancy, as well as detects any potential problems. Here are some key things to know before you go.
To determine gestational age, your doctor will measure the “crown to rump length” (top of head to bottom of tush). At 12 weeks, the average size is 5–6 centimeters.
Underdeveloped or absent nasal bones have been linked to a high rate of Down syndrome. Your doctor examines the nasal bones to begin ruling out any potential problems.
The thickness of the nuchal (or neck) fold is another marker for chromosomal abnormalities. The results, along with a blood test, can be used to detect issues as early as 11 weeks.
See that tiny darkgray circle right under the chin in the chest cavity? That bubble is the stomach starting to form, and your doctor will look to make sure it’s on track.
Depending how she’s positioned, you may not see all of baby’s arms and legs in the profile view (above), but your doctor takes a variety of angles to check on all of them.
Trying to figure out what's what? Use this distinction: On an ultrasound, fluid appears black, while bone is bright white.
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