Today's technology offers expectant parents and their doctors valuable information. Prenatal testing, however, can often be a source of tremendous stress and confusion. Jacques Abramowicz, MD, a fetal ultrasound expert and co-director of the Rush Fetal and Neonatal Medicine Center, offers the following information to help families better understand today's tests and the implications of their use:
Most children with Down syndrome are born to women under 35.
Although the incidence of Down syndrome increases with advancing maternal age, approximately 75 percent of babies with Down syndrome are born to women younger than 35 (more women in this age group have babies). Therefore, using maternal age alone is not an effective way to predict pregnancies that will result in Down syndrome. This is why screening tests are now offered routinely to all pregnant women, regardless of age.
Screening tests provide indications of risk, not diagnoses.
Doctors commonly use two tests to screen for genetic disorders like Down syndrome (as well as some forms of cardiac disease): the first trimester combined screening test, which is a blood test and an ultrasound to measure fluid behind the neck (known as nuchal translucency), and the quad screen, which is a blood test that evaluates four components of the blood. Apart, and together, these tests produce an assessment of a woman's likelihood of having a child with certain disorders. Women wanting a definitive diagnosis should undergo amniocentesis or chorionic villus sampling, which, with almost 100 percent certainty, can indicate if a baby has Down syndrome or some other genetic disorder.
Ultrasound does not carry the same risks as X-ray imaging.
Unlike X-rays, which use radiation to produce images, ultrasounds use sound waves. Although deemed safe in humans, ultrasound heats tissues and produces vibrations, and the long-term impact, if any, of these effects is unknown. To maintain safety, it is important to use ultrasound judiciously. It's also important for the person performing the ultrasound to pay close attention to indices that appear on screen, and to keep these within specific limits. This will ensure that potential bioeffects, such as temperature increases and vibrations, are minimal.
Skip the fetal glamour shots.
Ultrasound technology gives physicians the opportunity to examine babies in the womb. It can detect abnormalities in the skull, spine, heart and more. To guarantee safety and detection of abnormalities, this technology should be used only by trained professionals for diagnostic purposes in a clinical setting, not in a storefront ultrasound "studio."
When there's a concern regarding the findings of a standard ultrasound, a 3-D or 4-D (also called "live 3-D") ultrasound may be performed to help better delineate specific parts of the fetal anatomy. These are not routine procedures and should not be expected unless there is a clinical reason for performing these tests. When performed, a 3-D image (generally of the face) can be generated for the parents if the fetus is in the right position, there is sufficient fluid around the fetus and good images are obtained.
During a healthy pregnancy, two to three ultrasounds is the norm. Additional ultrasounds may be performed in cases of bleeding, suspicion of abnormalities or if there's a history of problems.
Get a second opinion.
If you received troubling results or if you having lingering questions about your unborn baby's health, definitely seek out another health care professional's opinion and ask to have the prenatal ultrasound repeated. This not only helps ensure that you get accurate information but also creates an opportunity to obtain different perspectives.
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Please note: All physicians featured in Discover Rush Online are on the medical faculty of Rush University Medical Center. Some of the physicians featured are in private practice and, as independent practitioners, are not agents or employees of Rush University Medical Center.
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