Ultrasounds

Expectant mothers may have questions around ultrasound so we have tried to answer the most popular questions below.

What are ultrasound scans used for?

Ultrasound scanning is used to help monitor and diagnose symptoms in many different parts of the body, including the kidneys, liver and heart.  It is most often used to examine conditions affecting the organs in a woman's pelvis - the uterus, Fallopian tubes and ovaries. Ultrasound scanning is not dangerous and has no side effects, so it is perfectly safe to use during pregnancy.

How do ultrasounds work?

A patient once said the ultrasound scanner looks like a small paint roller. I think this is an ideal description.  As it moves back and forth over the body, the scanner sends sound waves through the skin and muscles. These waves are reflected back at various strengths from the different parts of the body which paints the picture you see.  It is then turned into a 2D image that appears on a TV screen. The scan can then be put onto paper or CD for you to take with you.

How is an ultrasound scan performed?

The way the ultrasound scan is performed depends on the purpose of the examination. The scanner can be used externally on the skin, or through the vagina.

In a standard prenatal examination the patient will be asked to lie on their back or side on an examination table. Some special gel is spread over the exposed skin to ensure good contact with the skin.  This will help give a better picture. 

If all is well the examination itself should take around fifteen minutes.  If the baby is in an awkward position, you may be asked to get up and take a little walk or a drink to allow the baby to move around.  Sometimes the baby just doesn’t co-operate, and it is easier to just reschedule the appointment.

If a woman's pelvic organs are under examination, a transvaginal scan would provide a better image. This is a slightly more invasive procedure, but produces much more detail in the scan.  It is especially useful during early pregnancy.  A different type of transducer is used in this procedure, which is inserted three inches inside the vagina.  This gives a different view of the fetus but also includes the uterus and ovaries.  Although not as dignified as a standard ultrasound, it is also a valuable diagnostic technique, but only used if necessary.

Often you will be able to watch the screen as the scan unfolds, but not always.  The Sonographer or Radiologist will interpret your results and either give you a picture of the scan to take away with you or report directly to your physician.  These vary depending on the facility you visit.  Your Sonographer should let you know what to expect before starting the procedure.

Does an ultrasound scan hurt?

An ultrasound scan does not hurt at all, but the gel used for the examination can feel a bit cold!  The transvaginal scan may briefly feel a uncomfortable, but this passes quickly.

Where are ultrasound scans performed?

The examination has traditionally taken place in hospital, with patients being referred by their doctor. However, ultrasound is available in a small but growing number of medical clinics. Companies like Look Who’s Kickin’ also offer ultrasound services above and beyond what is normally provided by your medical practitioner.  This is so the parents-to-be can get more out of the experience.

When can they be performed?

The latest ultrasound scanners can detect the baby age after 8 weeks from the last missed period.  It can also determine the site of the pregnancy, whether intrauterine or ectopic at this time.  Not much more detail will be able to be seen until much later.

At 11 to 14 weeks the thickness of the skin at the back of the neck can be measured.  This is called ‘nuchal translucency’, and can be used to determine the risk of chromosome abnormalities. 

The sex can usually be determined after 16 weeks of pregnancy, but is normally seen at the dating scan at 20 weeks.  The 20 week point is also the best time to scan for anomalies, although if you are a high risk of this, a scan can be conducted earlier. 

From 18 weeks onwards, most organs can be examined.  The spine, skull, brain, organs, arms and legs can all be seen.

At 30 weeks it is possible to scan for the presentation of the fetus.  This determines of the baby is head down (vertex presentation), breech presentation or lying transversely.  This is a pivotal scan as the method of birth will be determined by the presentation of the baby.  At this time cesarean section is by far the most common method of birth for breech presentation.  This is also the time where the Sonographer can determine if the baby is growing as expected.

Having your ultrasound is your first opportunity to see your baby.  As a mother, you can feel it all the time, and the effects it has on your body.  Actually seeing him or her for the first time is a very emotional experience.  Having private ultrasounds is not in any way designed to replace the ones scheduled by your physician, but to add to them.  It will enable you to ‘meet’ your baby much more before he or she enters the world.  It is now accepted fact that bonds form earlier and stronger after an ultrasound, especially if you have a 3D/4D one, where you can see the baby in more of a recognisable form.  It also allows an expectant mother to share the experience with partners and loved ones, so they can all prepare for the new arrival!