
During the past 25 years Dr. DeVore has examined over 100,000 fetuses. Many patients have been referred for Routine or Screening Ultrasound of the fetus in which the referring physician did not suspect the patient to be at increased risk for problems. When Dr. DeVore inquired as to whether the patient or her family had any concerns, the majority confided that their biggest worry was whether the unborn "baby was healthy." The following are questions that a pregnant woman should consider.
Birth defects occur in 1 in 33 newborn babies and may be readily identified because of the external features of the abnormality. Examples may be a spinal cord defect, missing arm or leg, cleft lip or palate, or abnormal facial or head features. However, the majority of serious birth defects are silent--- they involve organs which the pediatrician cannot adequately examine. Examples are:
v Early hydrocephaly (water on the brain) or other abnormalities of the brain
v Heart defects
v Obstruction of the kidneys
v Blockage of the stomach or intestines
v Abnormalities of the lungs
The California Birth Defects Monitoring Program reviews many of the concerns and implications of birth defects.
When birth defects are present, but not identified at birth, the child may not become ill until after it is sent home with the parents, only to return with a medical emergency. This is especially important with short maternal stays in the hospital following delivery. It has been demonstrated that the prenatal diagnosis of birth defects may improve the outcome of the child, especially when the birth defects involve the heart or spine.
When one considers whether a screening test should be offered to patients, it is important to use a Gold Standard to compare whether the test which is being considered is equal to or superior to screening tests currently in use. Examples of screening tests would be the PAP smear for cervical cancer, mammography for breast cancer, and the maternal serum Triple or QUAD screening test to identify fetuses at increased risk for Down syndrome and other birth defects.
From its early inception, fetal ultrasound has been a useful diagnostic tool when utilized by experts to identify serious birth defects. It has received much attention in the medical literature as well as the public press during the past 30 years. Numerous textbooks, and thousands of medical articles have been written describing its use to identify birth defects. Given its diagnostic potential, physicians in the early 1980's advocated the use of ultrasound to screen for birth defects in women who were low risk; having no family history, or not exposed to drugs or environmental toxins. While ultrasound appeared to have promise as a screening tool, it later became apparent that its potential benefit was limited by the experience of the physician or technologist performing the examination. Let us explore this in more detail.
Over 20 years ago (June 20, 1995), Heidi Evans of the Wall Street Journal wrote an article entitled, Doctors Who Perform Fetal Sonograms Often Lack Sufficient Training And Skill. In the article, a prominent Professor of Radiology, Roy Filly, at the University of California Medical Center in San Francisco stated,
The article also stated ,
Representative Pat Schroeder, who co-authored the 1992 Mammography Quality Assurance Act, which requires physicians and facilities to meet high standards before mammograms can be performed, stated the following about fetal ultrasound, "The only thing worse than not having a sonogram is having a bad one." In addition, the article reported that the poor quality of ultrasound imaging was documented in a study in 1992, by U.S. Healthcare, in which they reported that in 141 second-trimester sonograms-the sonogram that is most crucial for detecting defects in fetal structures-the heart, brain, spine and kidneys were most often poorly or inadequately imaged. In 1994, US Healthcare required obstetricians pass a certification program, of only which 36% passed!
In 1993, the Routine Antenatal Diagnostic Imaging With Ultrasound Study (RADIUS) was published in the American Journal of Obstetrics and Gynecology in which the benefit of routine fetal ultrasound screening of low-risk pregnant women was conducted in hospitals and physicians offices throughout the United States. When compared to obstetricians or radiologists who practiced in a community hospital, the RADIUS study found that there was a significantly higher detection rate of serious birth defects if the ultrasound study was performed by physicians who had extensive training in fetal diagnosis. For example, if the ultrasound was performed by an obstetrician or radiologist at a non-referral center, 0% of serious heart defects were detected! In another paper analyzing the implications of the RADIUS study, it was reported that if screening ultrasound were performed by experienced physicians, it was the most cost effective method for detecting birth defects. In this study, the author proposed matching the cost of the ultrasound to the experience of the physician. If, for example, the obstetrician rarely detected birth defects, as reflected by the results of the RADIUS study, they should only be paid $50 for the ultrasound examination. If their detection rate was higher, then they should be reimbursed accordingly. This concept would save patients and insurance companies millions of dollars annually. The most important conclusion from the RADIUS study is that if the ultrasound examination is performed by obstetricians, community-based radiologists, or their technicians, over 85% of major birth defects and virtually all (99%) serious heart defects are missed! This is due to lack of experience of the physician who must divide his or her clinical activities among many different areas, thus precluding the necessary time required to develop expertise in this area of medicine.
While obstetricians may use ultrasound to determine the fetal heart beat during the first 12 weeks of pregnancy, or examine the amount of amniotic fluid in the last 12 weeks of pregnancy, serious concern has to be raised if they perform an examination of the fetus between 16 and 24 weeks of pregnancy to examine fetal anatomy. Because of the poor performance detecting birth defects as described above, patients should ask themselves whether they should have their screening examination performed by a physician with expertise in examination of fetal anatomy?
If a birth defect is identified during the ultrasound examination, the findings are discussed with you in detail. Information will be offered to assist your obstetrician in rendering care for you and your unborn child to insure in the best possible outcome.