Ultrasound - What Can We Learn?
Ultrasound is a painless, non-invasive procedure that uses sound waves to produce a visual image of the developing baby.
By looking at this visual image, the physician may be able to determine:
- How far along you are in your pregnancy
- Whether there is more than one baby
- Size and position of your baby
In most cases, a conductive jelly will be applied to the mother's abdomen and the transducer will be pressed onto your skin to obtain an image. The image will then appear on a monitor. A printout of your developing baby is provided to you.
All ultrasounds are performed by RDMS certified sonographers. An ultrasound uses sound waves to produce a visual image of your developing baby. Ultrasounds are extremely helpful in the first, second and third trimesters, and most women have at least one ultrasound exam during pregnancy.
In your first trimester, an ultrasound can enable us to determine the location of the pregnancy, the gestational age, and viability of the pregnancy. We are also able to assess unanticipated vaginal bleeding.
We can identify multiple gestation pregnancies (twin, triplet and beyond) 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. Sonography in the second trimester 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 fl uid volume, and the baby’s position and heart rate.
If you have a multiple gestation, your ultrasound could take much longer, because we are performing the full assessment on all 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 can give the probability that the babies are fraternal (just like siblings), or identical (share the same DNA or genetic material).
Ultrasounds that occur in your third trimester are most useful in determining the estimated weight and position of your baby. If the ultrasound is done late in the pregnancy (after 35 weeks), we can project the newborn weight. Sometimes it is necessary to perform a transvaginal ultrasound. In this case, the transducer is passed into the vaginal canal and is rotated to obtain an image. You may experience some pressure during this procedure.
The Maternal-Fetal Medicine & Genetics Center at St. Mary’s Hospital for Women & Children was the first in the Tri-State to offer Real Time 4-D Ultrasound. While 3-D sonography can show the contours of your developing baby, 4-D sonography offers live action images of your baby. This may provide additional information on the status of your baby.