At Maternal Fetal Medicine at Virginia Hospital Center, ultrasonography is performed by our group of medical sonographers, all registered through the ARDMS (American Registry for Diagnostic Medical Sonography). All our sonographers have completed a rigorous medical sonography curriculum, have passed a qualifying exam, take continuing medical education training, and undergo routine evaluations to assess their competency.
Our sonographers practice in conjunction with two Board-certified physicians, who have completed four years of an OB/Gyn residency and three years of Maternal-Fetal Medicine fellowship learning the nuances of the ultrasound diagnosis, treatment, and prognosis of many fetal disorders. The physicians speak with all patients having their first ultrasound in our office and personally scan each patient having her anatomy survey (see Second trimester ultrasound).
Ultrasound is extremely helpful in the first (0-14 weeks), second (14-28 weeks), and third (> 28 weeks) trimesters. Most women have at least one ultrasound exam during pregnancy.
First trimester ultrasound
In your first trimester, ultrasonography enables us to determine the location of the pregnancy, the number of fetuses, the gestational age, and viability of the pregnancy. We are also able to assess unanticipated vaginal bleeding.
We can identify twin (and triplet and beyond) pregnancies in the first trimester.
First trimester sonography called Nuchal Translucency Screening is used to assess the fetal neck to identify risk for Down Syndrome and other chromosomal abnormalities.
Finally, sonography in the first trimester is utilized to assess the uterus for fibroids, which are non-cancerous muscular growths more commonly identified in mothers over age 40. The ovaries and fallopian tubes are also easily imaged during the first trimester.
Second trimester ultrasound
Sonography in your second trimester determines or confirms gestational age. At this time, we can accurately determine the gender of your baby in virtually all pregnancies. The time for this examination varies from 45 to 75 minutes, depending on the position of the baby and the requirement for specific images. During this sonogram, frequently called the “Anatomy Scan,” we examine the baby’s head, heart, stomach, intestinal tract, kidneys, spine, arms, and legs. Screening for Down syndrome and other genetic abnormalities is also done during this time. In addition, we observe fetal movement and determine the placental location, cervical length, amniotic fluid volume, and the baby’s position and heart rate.
If you are having twins, your ultrasound will take twice as long because we are performing the full assessment on both babies. Therefore, the 20-week ultrasound for twins takes from 90 to 120 minutes. In addition to determining the size and position of each baby, we determine if the babies are fraternal (just like siblings), or identical (share the same DNA or genetic material).
Third trimester ultrasound
Sonography in your third trimester is most useful in determining the estimated weight and position of your baby. We again examine the location of the placenta, amount of amniotic fluid, and fetal heart rate. This exam, if you have been a patient in our practice previously, generally takes less than 40 minutes. If requested by your physician, we will perform an abdominal or vaginal sonogram to assess the length of the cervix and explain unanticipated vaginal bleeding. If the ultrasound is done late in the pregnancy (after 35 weeks), we can project the newborn weight.
Ultrasound after 40 weeks
In conjunction with non-stress testing (see section on Fetal Monitoring), your doctor may request an assessment of your amniotic fluid volume. After completing the non-stress testing portion of the exam, a brief ultrasound is done to determine the position of the baby, the location of the placenta, and the volume of amniotic fluid. This ultrasound should take no longer than 15 minutes. Unless requested by your physician, an estimation of the fetal weight is not performed.
(please see section on Fetal echocardiography)
Biophysical physical profile testing
If the fetal non-stress testing is suboptimal, we may perform a Biophysical profile. The testing incorporates the real-time assessment of fetal practice breathing and fetal movements of the spine, neck, arms, and legs. At this time, we also assess the amniotic fluid volume. This testing takes between 10 and 30 minutes.
Ultrasound as an adjunct to amniocentesis
(please see the section on Amniocentesis)
3-dimensional (and 4-dimensional) Ultrasound.
We employ 3D and 4D technology to help us to determine the severity and prognosis of a suspected birth defect.