For a clearer picture, the belly is covered with a gel and the woman may be asked to have a full bladder while the test is performed. This exam checks pregnancy dates, fetal growth and size, number of fetuses, placental location, and looks for major birth defects. Ultrasound is painless,but many women find that having a full bladder is quite uncomfortable. In early pregnancy, the uterus and fallopian tubes are closer to the vagina than to the surface of the belly. If ultrasound is needed very early in pregnancy, sound waves may be delivered by a probe inserted in to the vagina a technique called transvaginal ultrasound.
Ultrasound examination has many uses during pregnancy, answering a variety of medical questions.
Confirm more than one baby. Ultrasound may be used to see if a woman is pregnant with twins,triplets, or a larger number of fetuses. Verify due date. The size of the fetus,measured using ultrasound, helps doctors accurately estimate the baby's due date. Evaluate fetal growth.