What to Expect at Your 20-Week Ultrasound (for Pregnant Women)

For pregnant women at their 20-week ultrasound, learning if your baby is a boy or a girl can be an exciting discovery. That is, if one chooses to know before the big day arrives.

However, this ultrasound can reveal much more than the sex of the fetus.

So, it’s a good idea for expectant mothers to properly prepare themselves for the 20-week ultrasound, which is sometimes referred to as an anatomy scan. Knowing what the ultrasound entails and what questions to ask healthcare professionals are important in preparing for this all-important procedure at the midway point of the pregnancy.

What is a 20-week ultrasound?

Ultrasound imaging bounces high-frequency sound waves at body structures or tissues and detects the echoes that bound back toward the source of the waves. The angle and frequency of these echoes allow for the creation of a live video feed image of the inside of the body. During pregnancy, these images can provide valuable information that helps doctors monitor the health of the fetus and the mom.

An ultrasound, sometimes referred to as a sonogram, is not an X-ray. Unlike X-ray imaging, there is no radiation exposure with an ultrasound image. Because of this, ultrasound is commonly used during pregnancy without harming the unborn baby. No links have been found between ultrasound and birth defects, childhood cancer or developmental problems later in life.

By the end of the 20^th century, obstetric ultrasonography became a routine part of maternity care throughout the developed world. Modern technology has sharpened ultrasound imaging, giving caregivers a clear picture of the fetus inside its mother’s womb and providing essential information about the baby’s development, position and health.

The American College of Obstetricians and Gynecology says women should have at least one ultrasound exam during pregnancy. The most notable is one performed between 18 and 22 weeks, and thus, the name “20-week ultrasound.” When done at this point in the pregnancy, the test allows the doctors and technicians to check the fetus’s health and development and detect many congenital anomalies.

There are two ultrasound methods - transvaginal and transabdominal. With the transvaginal method, a wand-like device called a transducer is placed in the vagina to release sound waves and gather images. The transabdominal fetal ultrasound is done by moving a transducer over the abdomen. The type of ultrasound exam performed depends on what types of images the doctor needs.

What information does a 20-week ultrasound provide?

The ultrasound provides a complete scan of the fetus, providing a view of the baby’s brain and spine, face, abdomen, limbs and all four chambers of the heart. Technicians can also take measurements to determine the development of the fetus. Information gleaned from ultrasounds include:

• The fetus’s position, movement, breathing and heart rate
• An estimate of the fetus’s size and weight
• The amount of amniotic fluid in the uterus
• The location of the placenta
• The number of fetuses

How to prepare for a 20-week ultrasound

There is little physical preparation needed for the 20-week ultrasound. Some doctors require the expectant mother to drink four to six glasses of water before the test so that the bladder is full. There is virtually no discomfort during the procedure. A typical prenatal ultrasound takes 30-45 minutes but could take longer if the baby is reluctant to pose.

Questions to ask at a 20-week ultrasound

It’s a good idea to prepare questions for the sonographer or doctor before going in for the ultrasound. Some of the more common questions that health experts recommend that you ask include:

• Are the baby's organs growing normally?
• Is the placenta healthy?
• Are there any signs of down syndrome?
• Should I worry if anything abnormal shows in the ultrasound?

This procedure can be both a joyous and stressful experience for expectant mothers. Knowing what to expect can help limit anxiety.

And, parents can look forward to leaving the ultrasound appointment with the first pictures and video of the baby to share with family and friends.