Current screening efforts, consistent with the NIH consensus statement, have addressed each of these problems and, as a result, are more acceptable on public health and ethical grounds. The change in approach to SCD screening over time, as new facts and treatment opportunities emerge, illustrates that programs must have the flexibility to change over time, as the situation changes.

Neural Tube Defects

Neural tube defects (NTDs) are major birth defects affecting the brain and spinal column. These defects range from uniformly fatal to severely disabling conditions, and include spina bifida. In 1973, it was reported that maternal serum alpha-fetoprotein (MSAFP) levels are elevated in pregnancies where the fetus is affected with an open neural tube. Alpha-fetoprotein (AFP) is a normal fetal protein that is usually present in maternal serum, so a higher than normal level indicates that the fetus is leaking fetal protein, usually, but not always, from an open neural tube. Follow-up tests such as amniocentesis and ultrasonography are required to confirm the diagnosis. By 1977, several companies had developed MSAFP kits, but the American College of Obstetricians and Gynecologists (ACOG) and other groups opposed their use because of the test's inherently high false positive rate. Others opposed the program because, since there is no identifiable high-risk groups for NTDs, all pregnant women would have to be screened. In addition, some individuals find the screening program unacceptable because the only option for preventing the birth of a child with an NTD is to terminate the pregnancy. Another concern was that some areas did not have the amniocentesis and ultrasonography facilities necessary to follow up a positive MSAFP test result. There are concerns, therefore, relating to the third, fourth, and fifth public health screening principles.

In 1985, ACOG, apparently driven by a concern about malpractice litigation, issued a strongly worded alert to its members advising them to investigate the availability of the tests in their area, familiarize themselves with the procedure and follow-up tests, advise every prenatal patient of the availability of the test, and document this discussion and the patient's decision. ACOG did not, at this time, change its recommendation that the test not be used routinely. Two years later, ACOG, citing greater understanding of MSAFP and improvement in follow-up tests, and new findings about the association of MSAFP with Down's syndrome, concluded:

MSAFP screening for neural tube defects detection should now be undertaken in United States communities having expertise in ultrasound, genetic counseling, and amniocentesis. In communities in which these facilities are limited, it is still prudent to inform pregnant women of the availability of MSAFP screening. … Those communities not having appropriate facilities should attempt to



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