Prenatal Screening for Neural Tube Defects: A Choice for All Lee N. Muecke Perspectives in Biology and Medicine, Volume 36, Number 1, Autumn 1992, pp. 87-96 (Article) Published by Johns Hopkins University Press DOI: https://doi.org/10.1353/pbm.1993.0022
For additional information about this article https://muse.jhu.edu/article/400943/summary
Access provided at 18 Nov 2019 02:27 GMT from Carleton University Library
PRENATAL SCREENING FOR NEURAL TUBE DEFECTS: A CHOICE FOR ALL LEE N. MUECKE*
Introduction
Although the association between elevated maternal serum alphafetoprotein and neural tube defects was first recognized in 1972 and is now well established [1], population-based screening programs have yet to gain broad acceptance in this country. Various obstacles appear to be responsible for thwarting the successful implementation of screening, including anxiety among screening participants [2], false positive results [2], cost-effectiveness [3—5], and fear of coerced termination of pregnancy [6]. On the basis of prevalence and required burden of care, neural tube
defects qualify as a significant public health problem. They occur commonly, with a collective incidence for anencephaly and spina bifida of 1-2 per 1,000 live births [7]. AU these infants will die in the neonatal period if afflicted with anencephaly, as will one-third of those with open spina bifida. The majority (65%), however, survive [8] with permanent physical and/or mental disability and require varying degrees of lifetime chronic care.
Screening of maternal serum alpha-fetoprotein levels is now based on well-developed technology. Alpha-fetoprotein, a glycoprotein synthesized by the fetus, crosses the placenta and appears in maternal serum and is optimally measured at 16-18 weeks gestation. Correct interpretation of the screening result requires accurate knowledge of the mother's gestational age and is determined from normative data [8]. Elevated The author gratefully acknowledges the helpful comments of Drs. Frank Greenberg,
Guy Parcel, and Denise Simons-Morton. Work done at Center for Health Promotion Research and Development, University of Texas School of Public Health, 1200 Herman Pressler, Houston, Texas 77030.
*Present address: Examination Team Physician, NHANES III, 1650 Research Boulevard, Rockville, Maryland 20850. © 1992 by The University of Chicago. All rights reserved.
003 1 -5982/93/360 1-0796$0 1 .00
Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 87
values are determined by setting cut-off points that provide optimal sensitivity and specificity, and usually range from 2.5 to 4 "multiples of the mean" in the baseline reference population [9]. Sensitivity of the tests for open neural tube defects (with a cut-off at three standard deviations) ranges from 96 to 100 percent, while specificity is greater than 99 percent [9]. The number of false positives and false negatives is determined by the exact cut-off point chosen [8]. Women who screen
positive routinely receive a repeat screening, and if truly elevated, are referred for serial diagnostic procedures including ultrasound, amniocentesis, and serum acetylcholinesterase determination [9].
The detection capability of screening maternal serum alphafetoprotein levels has steadily expanded. In addition to neural tube defects, a variety of birth conditions can now be detected. High values can detect numerous genetic defects including omphalocele, Turner's syndrome with cystic hygroma, teratoma, or may simply indicate a multiple pregnancy [7, 9]. In addition to screening for high values, low values of maternal serum alpha-fetoprotein are now identified as a risk factor for Down syndrome (Trisomy 21) [7]. Thus, in light of the increased utility and refined technology of maternal serum alpha-fetoprotein screening, the public's health would be greatly benefitted if barriers to implementation can be successfully overcome. Background Steinbrook [6] notes that in the late 1970s an enthusiastic American
public embraced the notion of large screening programs for neural tube defects. Momentum was lost, however, due to the perceived threat of unnecessary abortions and concerns over possible misinterpretations of test results. Specific concerns associated with testing became evident following the nation's first statewide effort, in California, to implement screening for neural tube defects. Implemented in April 1986, California has eighteen statewide "prenatal diagnostic centers" [6, 10] that pro-
vide follow-up evaluation of women with positive results. This program has been criticized by physicians on the basis of patient anxiety [2], difficulty in laboratory standardization [2], and variable access to screening due to differing policies of reimbursement. For example, state-
funded medical insurance in California covers the $40 screening fee while some private insurers do not [3]. Fortunately, concerns about labo-
ratory inaccuracies have been largely allayed over the last decade by technical advances [9], and adequate quality control can now be achieved with proper regulation of laboratories performing the screening. The medical community, though, has been reluctant to move forward
with public health application of this screening test. Only in response to growing public awareness, the American College of Obstetrics and 88
Lee N. Muecke ¦ Neural Tube Defects
Gynecology issued an alert in 1985 that all obstetricians should offer
this screening to their patients due to "professional liability implications" [H]. Such a position suggests an effort to protect physicians from allegations of malpractice, in the event that they fail to offer the test to a woman who subsequently bears an affected infant and holds her physician responsible for the unanticipated outcome. Despite the lack of unified support by the medical community at large, the Public Health Service Expert Panel on the Content of Prenatal Care currently recommends that all pregnant women receive testing [12].
Citizens who rely on health care in public facilities are overrepresented by lower socioeconomic strata and minorities. Consequently, they are the unfortunate victims of public health policy that denies them access to current medical technology. They are less likely than those privately insured to be informed of current medical advances and unlikely to be routinely offered maternal serum alpha-fetoprotein testing in public health facilities. In the absence of a strong consensus recom-
mendation from the medical community for routine screening of maternal serum alpha-fetoprotein in all pregnant women, testing is not likely to be encouraged nor as readily available in public health facilities as in the private sector.
Proposed Program as Solution The majority of perceived resistance to screening may be overcome by offering the test in conjunction with a program of support services based on (1) maximal personal autonomy and (2) effective medical
practice. These core values underlie any discussion of barriers to population-based screening. Successful implementation can be achieved by
pairing screening with a carefully planned set of services that offers comprehensive support to all women screened, but includes a focused
effort to screen women who choose to carry affected, high-risk pregnan-
cies to term.
By predicating the screening test on a set of management options that genuinely increases personal choice, it is likely that screening would meet less resistance from both the public and the medical community. If the resistance that has thwarted implementation can be overcome by allaying fear and focusing efforts on optimization of the infant's outcome, broad-based population screening can be achieved. This will enable women to benefit on a much larger scale, by giving them the auton-
omy to manage their pregnancies according to their own value systems. Key to this proposal is that all management options serve to optimize the infant's health, regardless of the management option selected. Offering the proposed program in conjunction with screening would not only provide the medical community with an opportunity to imPerspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992
89
prove the health of affected infants, but it would enable them to demonstrate a sincere intent to provide each woman with a genuine choice in
managing her pregnancy. Medically, this approach is not only ethical
but sensible. Current evidence [13] suggests that many afflicted infants do not receive optimal or even adequate care during critical periods such as delivery. Such a deficit in care may seriously compromise their lifetime level of functioning.
A proposal to support women who decide to bear handicapped in-
fants may be erroneously perceived as actually encouraging this process,
resulting in a largely increased number of handicapped infants. However, closer examination reveals this is not a logical consequence. Calculations using real figures from California's experience [10] indicate that less than 18 percent of women have chosen to continue their pregnan-
cies when diagnosed with a neural tube defect, irrespective of the severity of the detected handicap. One must realize that all of the women carrying fetuses to term would theoretically have delivered affected infants, whether or not they received screening. Those women who knowingly do so represent a subset of this population and not additional cases. Because no clearly defined high-risk women exist, other than
those with a personal or family history, there is no threat of selectively encouraging high-risk individuals to attempt pregnancy who may otherwise have refrained. The net result is a greater than 80 percent reduction in affected births that otherwise would have occurred.
Support Services A woman informed that she is carrying a fetus with a neural tube defect may experience the event as a crisis. She must not only deal with the grief resulting from the symbolic loss of her anticipated healthy baby, but also with the immediate decision regarding termination of the pregnancy. Women who emerge from the medical evaluation having chosen to carry their fetuses to term require three important, ongoing
support services for an optimal outcome: psychological support, medical support, and economic support. psychological support
After receiving the diagnosis and deciding to proceed with the pregnancy, expectant parents should receive counseling to deal with the symbolic loss of a healthy child and to revise expectations regarding the anticipated birth. A British study of women who knowingly chose to
abort after having their fetus diagnosed with neural tube defects or chromosomal abnormalities showed that 77 percent experienced an
"acute grief reaction" [14], and 46 percent continued to experience de-
90
Lee N. Muecke ¦ Neural Tube Defects
pressive symptoms six months later. Not only should women who choose to abort receive supportive counseling; women who choose to keep their
babies might be afflicted with a similar depressive reaction to their new diagnosis and would benefit greatly from counseling as well. In addition to grief, prospective mothers experience a great deal of anxiety. A study [15] in which women were encouraged to role-play at having a defective infant revealed them to have several concerns, includ-
ing the expense of medical care, the effect on siblings and the marriage, and their own ability to cope with the situation. Supportive counseling would thus be valuable and might include the use of role-playing scenarios or the establishment of a "buddy system" with an experienced parent. Access to adequate social support is essential in light of the stigma
associated with handicaps in our society [16]. Parents may also require counseling to support their own relationship [17], and counseling should include the father regardless of his marital relationship with the mother.
medical support
Women who screen positive for a neural tube defect and choose to complete their pregnancy should receive systematic medical care specifically designed to follow them through the time of delivery. Although it is customary to closely monitor a woman's health during any high-risk pregnancy, medical interventions that might not otherwise be employed can achieve an optimal outcome for the fetus [18]. In addition to improved prenatal management, the delivery of the handicapped infant represents another important opportunity to intervene on the child's behalf [9, 13, 18, 19]. A recent report issued by the U.S. Civil Rights Commission and based on a five-year study concluded that infants born
with disabilities consistently receive inadequate lifesaving medical care [20]. More importantly, they found that physicians are primarily responsible because they make unfounded judgments about the infants' future potential function that are often erroneous. Additional evidence corroborates the positive impact a timely intervention can have on the birth outcome. A recent ten-year study in Wash-
ington has shown that performing a cesarean section delivery prior to the onset of labor "significantly improved" [13] motor function in infants born with spina bifida by avoiding trauma to the exposed nerves. Luthy noted the improved outcome of these infants may also be attributed to coordination of perinatal events and the scheduled delivery. Cesarean section deliveries not only minimize trauma [9, 19] but also decrease the risk of infection [9] in the delivery of an infant with an
open neural tube defect. A physician choosing not to intervene in the prenatal care of a defective developing child must weigh heavily the risk Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 | 91
of denying a young life every reasonable opportunity to have an optimal outcome such as improved motor function. Parents of chronically ill children often strive many years for the most humble of achievements, such as the mere turn of a head when they walk in the room. From a strictly medical perspective, simple preservation of bladder function can
prevent a lifetime of bladder infections, required hospitalizations, and possibly total renal failure.
Optimal coordination of services suggests that a pediatrician, ideally a neonatologist, be present at delivery as in any high-risk pregnancy. Many of these infants will require resuscitation, which is best provided
by a pediatrician. This is likely not a standard practice, since the American Academy of Pediatrics does not explicitly require the person resuscitating a newborn to be a physician [7], but rather lists the required training and skills that a qualified individual must possess. Deliveries
occurring in indigent health care settings, especially outside of training centers, are not likely to have the benefit of an experienced pediatrician. Making pediatricians available at births involving neural tube defects offers a valuable opportunity to prevent illness and improve the health
of these children.
Cooperation between obstetricians, pediatricians, and neurosurgeons is essential to achieving an optimal medical outcome, and patients should not be left to coordinate such services. Ideally, the expectant
parents should meet with a chosen pediatric neurosurgeon prior to the delivery [21], as a great deal of anxiety can be prevented if questions are answered in a straightforward fashion when parents are not emotionally
overwhelmed. It is doubtful that prospective mothers in public health settings ever receive such anticipatory attention. Finally, mothers should be educated by qualified health personnel, optimally a trained nurse [22], regarding the future medical care of the infant. The intent here is to encourage the development of clear guidelines
and protocols for providing these services. Such standardization will assure a more equitable delivery of health services, but it can only be
achieved if the medical community develops specific policies regarding the need for a routine high standard of care (i.e., American Academy of Pediatrics and American College of Obstetricians and Gynecologists policy statements). Such policies would legitimize high-risk pregnancy continuation as an option for women. This message of support for continuing pregnancy is required more than ever in light of a current trend toward "nonaggressive management" [23] in the obstetric care of defective infants. economic support
Infants born with handicaps require specialized medical care and ser-
vices, the cost of which can easily overwhelm an average family budget. 92
Lee N. Muecke ¦ Neural Tube Defects
Medical care requirements for infants born with neural tube defects range from several days or weeks in the neonatal intensive care unit (as
in anencephaly) to a lifetime of chronic expenses, including repeated hospitalizations, doctor visits, and rehabilitation efforts (as in spina bi-
fida). Taplin notes that a working group report published by the Harvard University Press estimates the "lifetime cost of medical care" [3] for an American child with a neural tube defect is greater than $87,274 based on 1987 dollars, a finding comparable to his own analysis. Virtually all mothers without medical insurance for their newborns, and many
mothers who exhaust their finite insurance coverage, will find their babies receiving medical care underwritten by their state and county. Each pregnant woman should begin investigating available resources soon after the diagnosis of a neural tube defect in order to avoid financial
catastrophe. Tragically, some families allow their financial and personal lives to be devastated when suddenly faced with exorbitant hospital ex-
penses. Ironically, this is a particular risk for families in middle and upper socioeconomic strata, who may exhaust large personal resources before seeking public assistance. In addition, a growing problem exists with newly diagnosed women in the private sector, who lose their insurability due to the results of genetic screening [24] and subsequently must rely on public funding.
Optimal preparation for the infant's delivery should realistically include financial considerations. Women anticipating a neural tube defect delivery are likely to worry a great deal about costly medical bills [15],
and early identification of available financial options would minimize
this source of anxiety. Experienced social workers are specialists in locating appropriate community services and funding sources for patients. They could best perform this service through an organized and timely contact with the mother.
Economic Considerations: State-Funded Screening Program The savings in lifetime medical care realized by the voluntary termination of neural tube defect pregnancies, because of sheer magnitude, should logically far offset the expense incurred in the supportive perinatal care of the relatively few infants identified with a neural tube defect or other disorder in utero that will be carried to term. Efforts to clearly
demonstrate the financial gains associated with screening have been hampered by the difficulty of measuring the costs associated with lifetime chronic care. Consequently, the few screening cost-effectiveness studies performed have been somewhat equivocal. While one analysis of population-based screening for neural tube defects questions the feasibility of screening programs in light of a possible declining neural tube
defects incidence [4], the Centers for Disease Control projected a nearly Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 93
two-to-one ratio of benefits to screening costs [5] but assumed that all women screening positive would abort. Taplin, et al. [3], concludes that cost-benefit of screening may ultimately lie with the state rather than with a private insurer, due to the long-term nature of economic gains associated with preventive screening.
A state-funded program, rather than an effort in the private sector, is proposed for a variety of reasons. First, a screening program offered by the state would make this service available to a currently underserved population. Second, a statewide referral network would make screening available to an optimal number of individuals. Third, states are in a
unique position to establish a new "standard of care" for pregnant women by formulating specific policy in regard to required testing. Once the test gains greater public exposure, the medical community at large is likely to respond by adopting similar practices. States are also in an excellent position to provide critical regulation of the laboratories performing the screen, and can thus better assure quality and reliability of results. Finally, due to the long-term nature of potential economic gains, it is likely the proposed program would only be economically feasible if underwritten at the state level rather than by private insurers.
Taplin's cost-benefit analysis [3], based on a conservative estimate of neural tube defects incidence (just less than 7 per 10,000 births), indicates a public screening program would actually result in a net cost to
a private insurer. Unlike the state, a private insurer is not responsible for educational and residential care and would not reap direct fiscal
benefits from a screening program. When considering the costs of lifetime care, however, Taplin, et al., found it cost-effective for a state to perform such screening and concluded with a strong recommendation of statewide screening programs [3]. CALIFORNIA AS MODEL
Due to the relatively small number of women who will actually deliver affected infants and require the additional services proposed, the actual cost to provide the proposed support services is not prohibitive. Poten-
tial savings will be obtained from the large majority of women who
make the informed and genuine choice to terminate their pregnancy following the implementation of state-wide screening. These savings should far outweigh both the costs of offering the screening test to
pregnant women and of providing services to those who choose to de-
liver.
The scope of relative expenditure is best demonstrated by identifying
the actual number of women in the California Maternal Serum AlphaFetoprotein Program which would require the proposed services. From April 1986 to June 1989 (39 months), the California Alpha-Fetoprotein 94
Lee N. Muecke ¦ Neural Tube Defects
Screening Program screened 642,000 women [10]. Of these, 3.7 percent (23,463) received follow-up diagnostic procedures through California's alpha-fetoprotein prenatal diagnostic centers, and approximately 2 percent (457) of these women were diagnosed with neural tube defects. In addition, just over 2 percent (490) of additional women were diagnosed with other birth defects, including Down syndrome and ventral wall defects. In total 457 cases of neural tube defects were detected, yielding an annual average of 141 cases per year. Over the 39-month period, just under 18 percent of the 457 women who tested positive for neural tube defects (including anencephaly, open spina bifida, and encephalocele) chose to continue their pregnancies. The rest opted to terminate pregnancy [10]. Based on these statistics, only about 25 women per year
would actually choose to continue a pregnancy affected by a neural tube defect in the state of California. Through the improved utilization of existing resources, a few trained professionals could likely provide the proposed program of services to these women without large expenditures by the state. Conclusion
The optimal management of a pregnancy with a neural tube defect requires a multidisciplinary approach, involving psychological support services, coordinated medical care, and assistance with financial manage-
ment. Many of these services may currently exist, but they are inadequately accessed. Only when these services are offered in a cohesive and organized manner will women feel they are genuinely being given a choice regarding pregnancy continuation at the time of diagnosis. As genetic engineering and medical technology continue to make advances, we should increase efforts to intervene in affected pregnancies
when parents choose not to terminate pregnancy [18]. Most importantly, however, the proposed program of support services should facilitate general acceptance of broad-based screening of maternal serum alphafetoprotein. By providing practical solutions to concerns that have comprised a critical resistance to implementation, screening for maternal serum alpha-fetoprotein can be successfully implemented and ultimately benefit public health at large. REFERENCES
1.Bopart, I., et al. Maternal serum alpha-fetoprotein screening for neural tube defects. Prenat. Diagn. 5:77-83, 1985. 2.Stillman, P. C, and Hoffman, J. K. Alpha-fetoprotein anxiety. West. J. Med. 145 (3):393, 1986. 3.Taplin, S. H.; Thompson, R. S.; and Conrad, A. Cost-justification of maternal serum alpha-fetoprotein screening. Med. Care 26 (12): 1185-1202, 1988. Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992
95
4.Campbell, T. L. Maternal serum alpha-fetoprotein screening: Benefits, risks, and costs./. Fam. Pract. 25 (5):461-467, 1987. 5.Layde, P. M.; von Allemn, S. D.; and Oakley, G. P. Maternal serum alphafetoprotein screening: A cost-benefit analysis. Am J. Public Health 69:566573, 1979.
6.Steinbrook, R. In California, voluntary mass prenatal screening. Hastings Cent. Rep., 1986. 7.Frigoletto, F. D., and Little, G. A., eds. Guidelines for Perinatal Care.
Washington D.C: American Academy of Pediatrics and the American College of Obstetricians and Gynecologists, 1988.
8.ACOG Technical Bulletin. Prenatal detection of neural tube defects. 99:1-6, 1986.
9.Main, D. M., and Mennuti, M. T. Neural tube defects: Issues in prenatal
diagnosis and counseling. Obstet. Gynecol. 67 (1):116, 1986. 10.California Dept. of Health Services. Alpha-Fetoprotein Update for Prenatal Care Providers. Fall 1989.
1 1 . American College of Obstetricians and Gynecologists. Professional Lia-
bility Implications ofAlpha-Fetoprotein Tests. Washington, D.C: Dept. of Profes-
sional Liability, May 1985.
12.U.S. Dept. of Health and Human Services, Public Health Service. Car-
ing for Our Future: The Content of Prenatal Care. Washington, D.C: U.S. Government Printing Office, 1989.
13.Luthy, D. A.; Wardinsky, T.; Shurtleff, D. B.; et al. Abstract 5. In Pro-
ceedings of the Society of Perinatal Obstetricians, Annual Meeting in New Orleans, 1989.
14.Lloyd, J., and Laurence, K. M. Sequelae and support after termination of pregnancy for fetal malformation. Med. Pract. 290 (23):907-909, 1985. 15.Arnold, J. R., and Winsor, E.J. The use of structured scenarios in genetic counseling. Clin. Genet. 25 (6):485-490, 1984.
16.Richardson, S. A.; Boodman, N.; Hastorf, A. H.; and Dornbush, S. M.
Cultural uniformity in reaction to physical disabilities. Am. Social. Rev.
26:241-247, 1961.
17.Sabbeth, B. F., and Leventhal, J. M. Marital adjustment to chronic childhood illness: A critique of the literature. Pediatrics 73 (6):762—768, 1984.
18.Clark, S. L., and Devore, G. R. Prenatal diagnosis for couples who would not consider abortion. Obstet. Gynecol. 73 (6)4035-1037, 1989. 19.Shurtleff, D. B.; Luthy, D. A.; Benedetti, T. J.; et al. The outcome of
pregnancies diagnosed as having a fetus with meningomyelocele. Kinderchirurgie Suppl. 1:50-52, 1987.
20.U.S. Civil Rights Commission Report. Sept. 22, 1989.
21.Boehm, F. H. Management of the unanticipated neural tube defect in late pregnancy. Clin. Obstet. Gynecol. 27 (1):7883, 1984. 22.Worthington, S. Genetic screening. JOGN Nursing Suppl. March/ April:32s-37s, 1984. 23.Chervenak, F. A., and McCullough, L. B. Nonaggressive obstetric management: An option for some fetal anomalies during the third trimester. JAMA 261 (23):3439-3440, 1989. 24.Goodman, D. Discrimination linked to genetic screening. American Medical News 9 June, 1989, 25-27.
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Lee N. Muecke ¦ Neural Tube Defects
For additional information about this article https://muse.jhu.edu/article/400943/summary
Access provided at 18 Nov 2019 02:27 GMT from Carleton University Library
PRENATAL SCREENING FOR NEURAL TUBE DEFECTS: A CHOICE FOR ALL LEE N. MUECKE*
Introduction
Although the association between elevated maternal serum alphafetoprotein and neural tube defects was first recognized in 1972 and is now well established [1], population-based screening programs have yet to gain broad acceptance in this country. Various obstacles appear to be responsible for thwarting the successful implementation of screening, including anxiety among screening participants [2], false positive results [2], cost-effectiveness [3—5], and fear of coerced termination of pregnancy [6]. On the basis of prevalence and required burden of care, neural tube
defects qualify as a significant public health problem. They occur commonly, with a collective incidence for anencephaly and spina bifida of 1-2 per 1,000 live births [7]. AU these infants will die in the neonatal period if afflicted with anencephaly, as will one-third of those with open spina bifida. The majority (65%), however, survive [8] with permanent physical and/or mental disability and require varying degrees of lifetime chronic care.
Screening of maternal serum alpha-fetoprotein levels is now based on well-developed technology. Alpha-fetoprotein, a glycoprotein synthesized by the fetus, crosses the placenta and appears in maternal serum and is optimally measured at 16-18 weeks gestation. Correct interpretation of the screening result requires accurate knowledge of the mother's gestational age and is determined from normative data [8]. Elevated The author gratefully acknowledges the helpful comments of Drs. Frank Greenberg,
Guy Parcel, and Denise Simons-Morton. Work done at Center for Health Promotion Research and Development, University of Texas School of Public Health, 1200 Herman Pressler, Houston, Texas 77030.
*Present address: Examination Team Physician, NHANES III, 1650 Research Boulevard, Rockville, Maryland 20850. © 1992 by The University of Chicago. All rights reserved.
003 1 -5982/93/360 1-0796$0 1 .00
Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 87
values are determined by setting cut-off points that provide optimal sensitivity and specificity, and usually range from 2.5 to 4 "multiples of the mean" in the baseline reference population [9]. Sensitivity of the tests for open neural tube defects (with a cut-off at three standard deviations) ranges from 96 to 100 percent, while specificity is greater than 99 percent [9]. The number of false positives and false negatives is determined by the exact cut-off point chosen [8]. Women who screen
positive routinely receive a repeat screening, and if truly elevated, are referred for serial diagnostic procedures including ultrasound, amniocentesis, and serum acetylcholinesterase determination [9].
The detection capability of screening maternal serum alphafetoprotein levels has steadily expanded. In addition to neural tube defects, a variety of birth conditions can now be detected. High values can detect numerous genetic defects including omphalocele, Turner's syndrome with cystic hygroma, teratoma, or may simply indicate a multiple pregnancy [7, 9]. In addition to screening for high values, low values of maternal serum alpha-fetoprotein are now identified as a risk factor for Down syndrome (Trisomy 21) [7]. Thus, in light of the increased utility and refined technology of maternal serum alpha-fetoprotein screening, the public's health would be greatly benefitted if barriers to implementation can be successfully overcome. Background Steinbrook [6] notes that in the late 1970s an enthusiastic American
public embraced the notion of large screening programs for neural tube defects. Momentum was lost, however, due to the perceived threat of unnecessary abortions and concerns over possible misinterpretations of test results. Specific concerns associated with testing became evident following the nation's first statewide effort, in California, to implement screening for neural tube defects. Implemented in April 1986, California has eighteen statewide "prenatal diagnostic centers" [6, 10] that pro-
vide follow-up evaluation of women with positive results. This program has been criticized by physicians on the basis of patient anxiety [2], difficulty in laboratory standardization [2], and variable access to screening due to differing policies of reimbursement. For example, state-
funded medical insurance in California covers the $40 screening fee while some private insurers do not [3]. Fortunately, concerns about labo-
ratory inaccuracies have been largely allayed over the last decade by technical advances [9], and adequate quality control can now be achieved with proper regulation of laboratories performing the screening. The medical community, though, has been reluctant to move forward
with public health application of this screening test. Only in response to growing public awareness, the American College of Obstetrics and 88
Lee N. Muecke ¦ Neural Tube Defects
Gynecology issued an alert in 1985 that all obstetricians should offer
this screening to their patients due to "professional liability implications" [H]. Such a position suggests an effort to protect physicians from allegations of malpractice, in the event that they fail to offer the test to a woman who subsequently bears an affected infant and holds her physician responsible for the unanticipated outcome. Despite the lack of unified support by the medical community at large, the Public Health Service Expert Panel on the Content of Prenatal Care currently recommends that all pregnant women receive testing [12].
Citizens who rely on health care in public facilities are overrepresented by lower socioeconomic strata and minorities. Consequently, they are the unfortunate victims of public health policy that denies them access to current medical technology. They are less likely than those privately insured to be informed of current medical advances and unlikely to be routinely offered maternal serum alpha-fetoprotein testing in public health facilities. In the absence of a strong consensus recom-
mendation from the medical community for routine screening of maternal serum alpha-fetoprotein in all pregnant women, testing is not likely to be encouraged nor as readily available in public health facilities as in the private sector.
Proposed Program as Solution The majority of perceived resistance to screening may be overcome by offering the test in conjunction with a program of support services based on (1) maximal personal autonomy and (2) effective medical
practice. These core values underlie any discussion of barriers to population-based screening. Successful implementation can be achieved by
pairing screening with a carefully planned set of services that offers comprehensive support to all women screened, but includes a focused
effort to screen women who choose to carry affected, high-risk pregnan-
cies to term.
By predicating the screening test on a set of management options that genuinely increases personal choice, it is likely that screening would meet less resistance from both the public and the medical community. If the resistance that has thwarted implementation can be overcome by allaying fear and focusing efforts on optimization of the infant's outcome, broad-based population screening can be achieved. This will enable women to benefit on a much larger scale, by giving them the auton-
omy to manage their pregnancies according to their own value systems. Key to this proposal is that all management options serve to optimize the infant's health, regardless of the management option selected. Offering the proposed program in conjunction with screening would not only provide the medical community with an opportunity to imPerspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992
89
prove the health of affected infants, but it would enable them to demonstrate a sincere intent to provide each woman with a genuine choice in
managing her pregnancy. Medically, this approach is not only ethical
but sensible. Current evidence [13] suggests that many afflicted infants do not receive optimal or even adequate care during critical periods such as delivery. Such a deficit in care may seriously compromise their lifetime level of functioning.
A proposal to support women who decide to bear handicapped in-
fants may be erroneously perceived as actually encouraging this process,
resulting in a largely increased number of handicapped infants. However, closer examination reveals this is not a logical consequence. Calculations using real figures from California's experience [10] indicate that less than 18 percent of women have chosen to continue their pregnan-
cies when diagnosed with a neural tube defect, irrespective of the severity of the detected handicap. One must realize that all of the women carrying fetuses to term would theoretically have delivered affected infants, whether or not they received screening. Those women who knowingly do so represent a subset of this population and not additional cases. Because no clearly defined high-risk women exist, other than
those with a personal or family history, there is no threat of selectively encouraging high-risk individuals to attempt pregnancy who may otherwise have refrained. The net result is a greater than 80 percent reduction in affected births that otherwise would have occurred.
Support Services A woman informed that she is carrying a fetus with a neural tube defect may experience the event as a crisis. She must not only deal with the grief resulting from the symbolic loss of her anticipated healthy baby, but also with the immediate decision regarding termination of the pregnancy. Women who emerge from the medical evaluation having chosen to carry their fetuses to term require three important, ongoing
support services for an optimal outcome: psychological support, medical support, and economic support. psychological support
After receiving the diagnosis and deciding to proceed with the pregnancy, expectant parents should receive counseling to deal with the symbolic loss of a healthy child and to revise expectations regarding the anticipated birth. A British study of women who knowingly chose to
abort after having their fetus diagnosed with neural tube defects or chromosomal abnormalities showed that 77 percent experienced an
"acute grief reaction" [14], and 46 percent continued to experience de-
90
Lee N. Muecke ¦ Neural Tube Defects
pressive symptoms six months later. Not only should women who choose to abort receive supportive counseling; women who choose to keep their
babies might be afflicted with a similar depressive reaction to their new diagnosis and would benefit greatly from counseling as well. In addition to grief, prospective mothers experience a great deal of anxiety. A study [15] in which women were encouraged to role-play at having a defective infant revealed them to have several concerns, includ-
ing the expense of medical care, the effect on siblings and the marriage, and their own ability to cope with the situation. Supportive counseling would thus be valuable and might include the use of role-playing scenarios or the establishment of a "buddy system" with an experienced parent. Access to adequate social support is essential in light of the stigma
associated with handicaps in our society [16]. Parents may also require counseling to support their own relationship [17], and counseling should include the father regardless of his marital relationship with the mother.
medical support
Women who screen positive for a neural tube defect and choose to complete their pregnancy should receive systematic medical care specifically designed to follow them through the time of delivery. Although it is customary to closely monitor a woman's health during any high-risk pregnancy, medical interventions that might not otherwise be employed can achieve an optimal outcome for the fetus [18]. In addition to improved prenatal management, the delivery of the handicapped infant represents another important opportunity to intervene on the child's behalf [9, 13, 18, 19]. A recent report issued by the U.S. Civil Rights Commission and based on a five-year study concluded that infants born
with disabilities consistently receive inadequate lifesaving medical care [20]. More importantly, they found that physicians are primarily responsible because they make unfounded judgments about the infants' future potential function that are often erroneous. Additional evidence corroborates the positive impact a timely intervention can have on the birth outcome. A recent ten-year study in Wash-
ington has shown that performing a cesarean section delivery prior to the onset of labor "significantly improved" [13] motor function in infants born with spina bifida by avoiding trauma to the exposed nerves. Luthy noted the improved outcome of these infants may also be attributed to coordination of perinatal events and the scheduled delivery. Cesarean section deliveries not only minimize trauma [9, 19] but also decrease the risk of infection [9] in the delivery of an infant with an
open neural tube defect. A physician choosing not to intervene in the prenatal care of a defective developing child must weigh heavily the risk Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 | 91
of denying a young life every reasonable opportunity to have an optimal outcome such as improved motor function. Parents of chronically ill children often strive many years for the most humble of achievements, such as the mere turn of a head when they walk in the room. From a strictly medical perspective, simple preservation of bladder function can
prevent a lifetime of bladder infections, required hospitalizations, and possibly total renal failure.
Optimal coordination of services suggests that a pediatrician, ideally a neonatologist, be present at delivery as in any high-risk pregnancy. Many of these infants will require resuscitation, which is best provided
by a pediatrician. This is likely not a standard practice, since the American Academy of Pediatrics does not explicitly require the person resuscitating a newborn to be a physician [7], but rather lists the required training and skills that a qualified individual must possess. Deliveries
occurring in indigent health care settings, especially outside of training centers, are not likely to have the benefit of an experienced pediatrician. Making pediatricians available at births involving neural tube defects offers a valuable opportunity to prevent illness and improve the health
of these children.
Cooperation between obstetricians, pediatricians, and neurosurgeons is essential to achieving an optimal medical outcome, and patients should not be left to coordinate such services. Ideally, the expectant
parents should meet with a chosen pediatric neurosurgeon prior to the delivery [21], as a great deal of anxiety can be prevented if questions are answered in a straightforward fashion when parents are not emotionally
overwhelmed. It is doubtful that prospective mothers in public health settings ever receive such anticipatory attention. Finally, mothers should be educated by qualified health personnel, optimally a trained nurse [22], regarding the future medical care of the infant. The intent here is to encourage the development of clear guidelines
and protocols for providing these services. Such standardization will assure a more equitable delivery of health services, but it can only be
achieved if the medical community develops specific policies regarding the need for a routine high standard of care (i.e., American Academy of Pediatrics and American College of Obstetricians and Gynecologists policy statements). Such policies would legitimize high-risk pregnancy continuation as an option for women. This message of support for continuing pregnancy is required more than ever in light of a current trend toward "nonaggressive management" [23] in the obstetric care of defective infants. economic support
Infants born with handicaps require specialized medical care and ser-
vices, the cost of which can easily overwhelm an average family budget. 92
Lee N. Muecke ¦ Neural Tube Defects
Medical care requirements for infants born with neural tube defects range from several days or weeks in the neonatal intensive care unit (as
in anencephaly) to a lifetime of chronic expenses, including repeated hospitalizations, doctor visits, and rehabilitation efforts (as in spina bi-
fida). Taplin notes that a working group report published by the Harvard University Press estimates the "lifetime cost of medical care" [3] for an American child with a neural tube defect is greater than $87,274 based on 1987 dollars, a finding comparable to his own analysis. Virtually all mothers without medical insurance for their newborns, and many
mothers who exhaust their finite insurance coverage, will find their babies receiving medical care underwritten by their state and county. Each pregnant woman should begin investigating available resources soon after the diagnosis of a neural tube defect in order to avoid financial
catastrophe. Tragically, some families allow their financial and personal lives to be devastated when suddenly faced with exorbitant hospital ex-
penses. Ironically, this is a particular risk for families in middle and upper socioeconomic strata, who may exhaust large personal resources before seeking public assistance. In addition, a growing problem exists with newly diagnosed women in the private sector, who lose their insurability due to the results of genetic screening [24] and subsequently must rely on public funding.
Optimal preparation for the infant's delivery should realistically include financial considerations. Women anticipating a neural tube defect delivery are likely to worry a great deal about costly medical bills [15],
and early identification of available financial options would minimize
this source of anxiety. Experienced social workers are specialists in locating appropriate community services and funding sources for patients. They could best perform this service through an organized and timely contact with the mother.
Economic Considerations: State-Funded Screening Program The savings in lifetime medical care realized by the voluntary termination of neural tube defect pregnancies, because of sheer magnitude, should logically far offset the expense incurred in the supportive perinatal care of the relatively few infants identified with a neural tube defect or other disorder in utero that will be carried to term. Efforts to clearly
demonstrate the financial gains associated with screening have been hampered by the difficulty of measuring the costs associated with lifetime chronic care. Consequently, the few screening cost-effectiveness studies performed have been somewhat equivocal. While one analysis of population-based screening for neural tube defects questions the feasibility of screening programs in light of a possible declining neural tube
defects incidence [4], the Centers for Disease Control projected a nearly Perspectives in Biology and Medicine, 36, 1 ¦ Autumn 1992 93
two-to-one ratio of benefits to screening costs [5] but assumed that all women screening positive would abort. Taplin, et al. [3], concludes that cost-benefit of screening may ultimately lie with the state rather than with a private insurer, due to the long-term nature of economic gains associated with preventive screening.
A state-funded program, rather than an effort in the private sector, is proposed for a variety of reasons. First, a screening program offered by the state would make this service available to a currently underserved population. Second, a statewide referral network would make screening available to an optimal number of individuals. Third, states are in a
unique position to establish a new "standard of care" for pregnant women by formulating specific policy in regard to required testing. Once the test gains greater public exposure, the medical community at large is likely to respond by adopting similar practices. States are also in an excellent position to provide critical regulation of the laboratories performing the screen, and can thus better assure quality and reliability of results. Finally, due to the long-term nature of potential economic gains, it is likely the proposed program would only be economically feasible if underwritten at the state level rather than by private insurers.
Taplin's cost-benefit analysis [3], based on a conservative estimate of neural tube defects incidence (just less than 7 per 10,000 births), indicates a public screening program would actually result in a net cost to
a private insurer. Unlike the state, a private insurer is not responsible for educational and residential care and would not reap direct fiscal
benefits from a screening program. When considering the costs of lifetime care, however, Taplin, et al., found it cost-effective for a state to perform such screening and concluded with a strong recommendation of statewide screening programs [3]. CALIFORNIA AS MODEL
Due to the relatively small number of women who will actually deliver affected infants and require the additional services proposed, the actual cost to provide the proposed support services is not prohibitive. Poten-
tial savings will be obtained from the large majority of women who
make the informed and genuine choice to terminate their pregnancy following the implementation of state-wide screening. These savings should far outweigh both the costs of offering the screening test to
pregnant women and of providing services to those who choose to de-
liver.
The scope of relative expenditure is best demonstrated by identifying
the actual number of women in the California Maternal Serum AlphaFetoprotein Program which would require the proposed services. From April 1986 to June 1989 (39 months), the California Alpha-Fetoprotein 94
Lee N. Muecke ¦ Neural Tube Defects
Screening Program screened 642,000 women [10]. Of these, 3.7 percent (23,463) received follow-up diagnostic procedures through California's alpha-fetoprotein prenatal diagnostic centers, and approximately 2 percent (457) of these women were diagnosed with neural tube defects. In addition, just over 2 percent (490) of additional women were diagnosed with other birth defects, including Down syndrome and ventral wall defects. In total 457 cases of neural tube defects were detected, yielding an annual average of 141 cases per year. Over the 39-month period, just under 18 percent of the 457 women who tested positive for neural tube defects (including anencephaly, open spina bifida, and encephalocele) chose to continue their pregnancies. The rest opted to terminate pregnancy [10]. Based on these statistics, only about 25 women per year
would actually choose to continue a pregnancy affected by a neural tube defect in the state of California. Through the improved utilization of existing resources, a few trained professionals could likely provide the proposed program of services to these women without large expenditures by the state. Conclusion
The optimal management of a pregnancy with a neural tube defect requires a multidisciplinary approach, involving psychological support services, coordinated medical care, and assistance with financial manage-
ment. Many of these services may currently exist, but they are inadequately accessed. Only when these services are offered in a cohesive and organized manner will women feel they are genuinely being given a choice regarding pregnancy continuation at the time of diagnosis. As genetic engineering and medical technology continue to make advances, we should increase efforts to intervene in affected pregnancies
when parents choose not to terminate pregnancy [18]. Most importantly, however, the proposed program of support services should facilitate general acceptance of broad-based screening of maternal serum alphafetoprotein. By providing practical solutions to concerns that have comprised a critical resistance to implementation, screening for maternal serum alpha-fetoprotein can be successfully implemented and ultimately benefit public health at large. REFERENCES
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