Prenatal ultrasound, also called fetal ultrasound, obstetrics ultrasound, pregnancy ultrasound, baby ultrasound or OB/GYN ultrasound, is an imaging test that uses high-frequency sound waves to create images of a developing baby inside the uterus. Ultrasound is a key imaging method used in women's health. These ultrasound images also help examine the mother’s reproductive organs, either through the abdomen or through the vaginal cavity. It is a diagnostic procedure that helps detect abnormalities and conditions related to fetus development and pregnancy. Diagnostic ultrasound has no side effects and is considered safe when used appropriately during pregnancy.
During the first trimester of pregnancy, an ultrasound is performed to confirm a viable pregnancy, confirm heartbeat, discard molar or ectopic pregnancies, measure the crown-rump length and calculate gestational age, and assess abnormal gestation. These are sometimes referred to as pregnancy sonograms. This is usually performed using transvaginal ultrasound, which is also called endovaginal ultrasound, where a small, wand shaped ultrasound probe is inserted into the vagina to get clearer imaging of the tiny, developing fetus.
During the second trimester, prenatal ultrasound helps diagnose fetal malformations (being performed at weeks 13-14 for Down Syndrome and at weeks 18-20 for congenital malformations), structural abnormalities, verify growth and gestational age, confirm multiple pregnancy, confirm intrauterine death, identify abnormalities in amniotic fluid (polyhydramnios or oligohydramnios), and evaluate the fetal being.
During the third trimester, prenatal ultrasound is used to confirm intrauterine death, identify placental location, observe fetal presentation and movements, observe the placenta, evaluate fetal well-being and identify pelvic and uterine abnormalities of the mother.
2-D ultrasound is commonly used for diagnostic purposes, but3-D imaging is offered by most centers for an add on cost. The 3D baby ultrasound imaging allows parents to see their baby for the first time in a realistic view prior to birth.