Routine ultrasound scanning of all pregnant women early in pregnancy is recommended by some, but not all authorities.

• Introduction to Ultrasound
• 1st Trimester Ultrasound Scanning
• 2nd and 3rd Trimester Ultrasound Scanning

A routine ultrasound scan early in pregnancy can be very useful, because it identifies those destined to miscarry, those with an ectopic pregnancy, multiple gestations, and those whose gestational age does not agree with their LMP, preventing misunderstandings and inappropriate intervention later in pregnancy. Early ultrasound scans are effective in detecting many fetal abnormalities.

Later in pregnancy, routine scanning can identify growth abnormalities, abnormalities in fetal position, some congenital anomalies, and can be a very satisfying experience for the mother and her partner.

Medically-indicated ultrasound scans may also be needed during pregnancy. Ultrasound is used to evaluate vaginal  bleeding or pain, and discrepancies between the measured size of the uterus and the expected size. It may be used to look for multiple gestations, such as twins or triplets, determine the position of the fetus, and assess fetal growth. Later in pregnancy, it may be used to evaluate fetal well-being, amniotic fluid volumes, and to estimate fetal weight.