Ultrasound is performed routinely during pregnancy. Early in the pregnancy it might be used to determine the size of the uterus or the fetus, to detect multiple or ectopic (outside the uterus) pregnancy, to confirm that the fetus is alive (or viable), or to confirm the due date. Toward the middle of the pregnancy (at about 16-20 weeks), ultrasound may be used to confirm fetal growth, to reveal defects in the anatomy of the fetus, and to check the placenta. Toward the end of pregnancy, it may be used to evaluate fetal size, position, growth, or to check the placenta.
When ultrasound is performed early in pregnancy, both transabdominal and transvaginal scans are generally performed. In the fourth through ninth months, only transabdominal scans are usually done.
During your obstetrical ultrasound you will be able to see your baby on the display screen utilized by the technologist. You will hear the baby’s heartbeat, as Doppler is part of the examination. In addition, you may note the technologist using computerized tools to measure various structures on the screen. These measurements, which include the baby’s head, abdomen, and legs, are used to assess the baby’s growth and confirm correct dating of the pregnancy. The baby’s anatomy is evaluated in detail as well.