“A review of over 50 medical studies shows that ultrasounds do not pose any danger to moms or fetuses. They do not cause birth defects, childhood developmental or intellectual problems, or cancer.”

Most healthy women receive two ultrasound scans during pregnancy. "The first is, ideally, in the first trimester to confirm the due date, and the second is at 18-22 weeks to confirm normal anatomy and the sex of the baby," explains Mendiola.

Pregnancy care providers can detect an embryo on an ultrasound as early as six weeks into the pregnancy. An embryo develops into a fetus around the eighth week of pregnancy. If your last menstrual period isn't accurate, it's possible that it may be too early to detect a fetal heart rate.

How does early pregnancy look on ultrasound scan? For the first two weeks after a missed period early pregnancy appears on the scan as a small fluid filled bubble as the embryo (future baby) is too small to be seen yet.