Ultrasound is a technique that uses sound waves to take a picture of the fetus in the womb. Ultrasound works by bouncing sound waves off the developing fetus. Echoes from the waves are converted into an image, called a sonogram, on a TV monitor.
For pregnancy scanning, sound waves are usually sent by a hand-held devise, called a transducer, rubbed back and forth across the abdomen. If ultrasound is done in very early pregnancy, or on certain other occasions, a vaginal ultrasound may be needed by inserting a small probe into the vagina.
Ultrasound of the fetal anatomy may detect some major structural anomalies. Good visualization of the fetus can help rule out 90% of open spinal abnormalities and 70% of other abnormalities. The evaluation may be limited by position of the fetus, stage of pregnancy, amount of amniotic fluid, how easily the sound waves penetrate the maternal abdominal tissue, etc. It should be noted that ultrasound cannot detect all abnormalities with 100% accuracy.
Your doctor has referred you for a targeted (Level II) ultrasound. In our office, this is performed by Dr. Radha Cherukuri or Dr. Daniel Wechter who will discuss the results with you at your appointment.