Love your ultrasounds

An ultrasound scan is your chance to “meet” your baby. Here’s why these scans are important and why you’ll love them too, writes Tina Otte

ULTRASOUND CAN BE used as a simple screening test or for a more in-depth diagnostic test. The use of ultrasound makes it possible to “see” inside the womb using sound waves. High frequency sound waves transmitted into the body bounce back from changes in density of different surfaces, such as those found in the body (fat, muscle, body organs and bone). Although ultrasound scanning is considered to be safe, some mothers still refuse to have one, as they feel there’s not enough long-term evidence of safety, and should only be done if a problem is suspected and a diagnostic ultrasound needs to be done. But there are many times when exposure to ultrasound gives valuable information that will clearly improve the outcome of a pregnancy.

HOW IS A SCAN CONDUCTED?

A transabdominal ultrasound is painless and noninvasive. The mother is usually required to drink plenty of fluids beforehand and asked to keep her bladder full. This will help to push the uterus out of the pelvic cavity in early pregnancy. The mother will lie flat on a bed and gel is applied liberally to her abdomen – this will help with the conduction of the sound waves. A transducer probe is moved back and forth along the mother’s abdomen, which picks up the sound waves, feeding them into a computer that then displays the image on a screen. Gradually, the uterine contours, bladder or placenta and foetus are revealed in a moving picture. The scan’s accuracy rate is dependent on the skill of the operator, and the interpretation of ultrasound varies among those who administer them. Since the development of ultrasound, methods and techniques have come a long way. Instead of looking at a screen that looks like it could be the surface of the moon, scans today can show your baby’s face in great detail. These are just some of the methods that use different imaging centres that perform the ultrasounds:

• A-mode (amplitude mode) – This is the simplest method of performing an ultrasound.

• B-mode or 2D mode – This is a twodimensional way of viewing the image of the foetus.

• 3D ultrasound – This is the most commonly use ultrasound technique by most obstetricians. This will show the three-dimensional picture of your growing baby.

• 4D ultrasound – This is similar to the 3D imaging, but provides the real-time image of the foetus.

ULTRASOUND MAY BE USED TO

• Confirm your due date by measuring the size of the foetus between 16 to 20 weeks’ gestation, or earlier.

• Check if you might be carrying more than one baby.

• Check for an intrauterine device that may have been in place as a method of birth control.

• Monitor the growth of your baby.

• Detect any abnormalities of the foetus.

• Offer a window in the womb during an amniocentesis or chorionic villus sampling.

• Measure the amount of amniotic fluid in the womb.

• May detect the source of any abnormal uterine blood loss.

• Check for a molar pregnancy, ectopic pregnancy or miscarriage if there has been no foetal movement by week 22, or if movements stop.

• In some cases, determine the baby’s sex. Success of this has a lot to do with baby’s position and the skill of the person doing the ultrasound.

• Assess the condition of the placenta if baby is small.

• Determine the state of the cervix to check whether it has started to dilate prematurely.