But ultrasounds can also lift the lid on a few worries you might be having. The main reason for the ultrasound is to work out how many weeks pregnant you are, and to estimate your due date.
In September 2014, the American College of Gynecologists and Obstetricians along with the American Institute of Ultrasound in Medicine and the Society for Maternal-Fetal Medicine, released new guidelines for physicians and other health care providers for accurately estimating due dates for pregnant women.
For example, about one in 20 women will appear to be at high risk from the nuchal translucency ultrasound to assess the risk of Down's syndrome, but most of these babies will turn out not to have Down's syndrome. Now that you know all about ultrasounds scans, test your new-found knowledge by taking our quiz!
It's up to you whether you have an ultrasound - you don't have to if you don't want to.
But there can be other issues at play, such as when a woman has had sex with two men since her last menstrual period, for instance.
Or perhaps she had irregular cycles and needs to pinpoint a more specific date in a timeline to accurately plan for the baby's birth. Using a calendar type system, you figure a due date by adding 280 days to last menstrual period, or equaling 40 weeks.
Having an ultrasound in the first trimester of pregnancy can be a thrilling experience. Bear in mind that you may need a second ultrasound before you know for certain if all is well.