Obstetric ultrasonography, commonly referred to as prenatal or pregnancy ultrasound, creates pictures of a growing embryo or foetus using high-frequency sound waves. In addition to checking the placentas blood flow, the procedure also checks the mothers ovaries, uterus, and uterus. Obstetric ultrasound data is used by medical professionals to monitor pregnancy development, determine gestational age, and assist with delivery date prediction. A nuchal translucency (NT) test is an optional ultrasound performed in the first trimester of pregnancy. It helps determine your babys risk of congenital conditions like Down syndrome. Its highly accurate at detecting conditions when combined with other first-trimester screenings.