For roughly 70 percent of all pregnant women, the first picture of their baby is a blurry ultrasound image. Most doctors use this sonar-based technology regularly, and a growing number of insurance plans cover at least one ultrasound test during pregnancy.
But what can a scan really tell you -- and your doctor -- about the baby? "A lot," says Frank Chervenak, M.D., director of fetal medicine at Cornell Medical Center, in New York City. Experts agree ultrasound can be an important tool for diagnosing conditions throughout pregnancy, from the causes of unexplained maternal bleeding during the first trimester to the levels of amniotic fluid in the last.
Because of the size and development of the fetus, most doctors prefer to do a routine scan during a woman's second trimester, usually at 18 to 20 weeks. This is a good time to gauge gestational age and growth, and to check for multiple fetuses. The doctor should also survey your baby's anatomy to try to ascertain any problems.
