Why Is Baby’s Head So Big in the Sonogram?

Whoa! My baby’s head looks huge in the sonogram. Why is that?
ByStuart Fischbein, MD
OB-GYN
Updated
Feb 2017
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Nope, it’s not an optical illusion. Your baby’s head really is big in proportion to his body right now.

At 11 weeks of pregnancy, baby’s head is about half the length of his body. Gradually, the body lengthens out and by about 28 weeks of pregnancy, baby’s body and head look a whole lot closer to normal. But it still won’t be in the same proportion as your head is to your body. At birth, a baby’s head is typically about one-fourth of his body length. Yours is just one-seventh of your height.

No wonder babies seem so top-heavy!

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