An ultrasound exam is a procedure that uses high-frequency sound waves to scan a woman’s abdomen and pelvic cavity, creating a picture (sonogram) of the baby and placenta. Although the terms ultrasound and sonogram are technically different, they are used interchangeably and reference the same exam.

The data calculated below is based on a single baby and not twins. The best viewing time for twins is 24 to 26 weeks.