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Weekend Doctor: Prenatal ultrasounds

By Lauren Nussbaum, RDMS
Women’s Health Sonographer
Blanchard Valley Obstetrics & Gynecology 

Ultrasound is an imaging modality that uses sound waves transmitted into the body to create a picture of internal structures. Ultrasound can be used to image a baby developing inside the womb and has become a routine part of prenatal care. Most patients will get at least two or three diagnostic ultrasounds throughout their pregnancy.

Expectant parents look forward to seeing their baby on the ultrasound screen. Many times, the baby can be seen sucking their thumb, waving their hand or kicking their feet with the ultrasound. With the advancement in 3D/4D ultrasound, the baby’s facial features can even be well visualized on some occasions. The opportunity to see the baby before they are born can be a bonding experience and is an exciting time for the expectant parents. 

Prenatal ultrasounds do serve a purpose other than bonding, however. Prenatal ultrasounds performed in a medical facility, such as an obstetric office or hospital, are ordered for diagnostic purposes to ensure that both the mom and baby are healthy and thriving. These ultrasound exams are performed by a diagnostic medical sonographer and read by the obstetrician or radiologist.

The routine fetal anatomy ultrasound is usually performed between 20 and 22 weeks of pregnancy, when the baby is developed enough to obtain the diagnostic information needed, but still small enough to allow for adequate angles to obtain all required views. Many times, this ultrasound is thought of as the “gender scan,” but there is so much more to it than revealing if a baby boy or a baby girl is on the way. 

The routine fetal anatomy ultrasound is usually the only time in the pregnancy that the baby is scanned from head to toe. The sonographer will obtain several measurements to confirm that the baby is growing appropriately. The baby’s internal organs will be assessed to ensure that these organs are developing properly and rule out any congenital abnormality. Several views of the baby’s heart will be obtained to rule out congenital heart defects. Special attention will be given to structures within the developing baby’s brain. The spine and limbs will be thoroughly evaluated. The baby’s facial structure will be assessed. The sonographer will pay close attention to several areas that are seen as “soft markers” for genetic abnormalities. 

If any abnormalities or soft markers are discovered, this would alert the care team to consider further testing for several genetic conditions. A referral may be made to a specialist for a more in-depth evaluation, based on the ultrasound results. 

The sonographer will also assess the placenta and umbilical cord, amniotic fluid level and maternal uterus and cervix during this ultrasound. This allows the care team to be aware of any maternal complication that may also arise in the pregnancy.

Ultrasound, especially the routine fetal anatomic survey, plays an important role in obstetrical care as it provides useful diagnostic information that aids the care team in providing quality care for a healthy pregnancy and delivery.