Journal of Applied Genetics

, Volume 47, Issue 2, pp 151–158 | Cite as

The impact of prenatal diagnosis on neural tube defect (NTD) pregnancy versus birth incidence in British Columbia

  • Margot I. Van Allen
  • Erin Boyle
  • Paul Thiessen
  • Deborah McFadden
  • Douglas Cochrane
  • G. Keith Chambers
  • Sylvie Langlois
  • Patricia Stathers
  • Beverly Irwin
  • Elizabeth Cairns
  • Patrick MacLeod
  • Marie -France Delisle
  • Soo -Hong Uh
Article

Abstract

The birth incidence of neural tube defect (NTD) cases in British Columbia (B.C.), and elsewhere in North America, is reported to be declining. This decline is being attributed to folic acid (FA) supplementation and food fortification, but 2nd trimester prenatal screening of pregnancies for NTDs and other congenital anomalies has increased during this timeframe, as well. This descriptive, population-based study evaluates the impact of prenatal screening of NTD-affected pregnancies on (1) pregnancy outcome and (2) reporting of NTD births to the provincial Health Status Registry (B.C.H.S.R.); and it assesses (3) the use of periconceptional FA supplementation. NTD cases were ascertained from medical records of health centres providing care to families with NTD-affected pregnancies and newborns; and from NTD cases reported to the B.C.H.S.R. In 1997–1999, the B.C.H.S.R. published a NTD incidence of 0.77/1000. In this study, 151 NTD-affected pregnancies were identified, with an incidence of 1.16/1000. Partial Reporting of induced abortions in a NTD incidence 45.5% low than the actual incidence. Medical records were available for review on 144/151 pregnancies. Prenatal screening identified 86.1% (124/144) of NTD-affected pregnancies, with 72.6% (90/124) resulting in pregnancy termination, and 27.4% (34/124) continuing to term. Use of FA supplementation in the periconceptional period was recorded in 36.4% of pregnancies (39/107). Thus in B.C. the decline in the NTD incidence is due predominantly to pregnancy terminations following prenatal diagnosis, which reduces the NTD incidence by 60%, from 1.16/1000 to 0.47/1000. Continued efforts for primary and the option of secondary prevention of NTDs are recommended in order to improve newborn health in B.C. and elsewhere. These interventions need to be monitored, however, for optimal health care planning.

Key words

anencephaly B.C. Health Status Registry birth defects registry folic acid incidence of NTDs neural tube defects NTD pregnancy outcome prenatal diagnosis of NTDs prevention of NTDs spina bifida 

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References

  1. Allen WP, Stevenson RE, Thompson SJ, Dean JH, 1996. The impact of prenatal diagnosis on NTD surveillance. Prenatal Diagnosis 16: 531–535.CrossRefPubMedGoogle Scholar
  2. Berry RJ, Li Z, Erickson JD, et al. 1999. Prevention of neural-tube defects with folic acid in China. China-U.S. Collaborative Project for Neural Tube Defect Prevention. N Engl J Med 341: 1485–1490. (Erratum in: N Engl J Med, 1999. 341: 1864).CrossRefPubMedGoogle Scholar
  3. Brent RL, Oakley GP, Mattison Dr. 2000. The unnecessary epidemic of folic acid-preventable spina bifida and anencephaly. Pediatrics 106: 825–827.CrossRefPubMedGoogle Scholar
  4. Castilla EE, Orioli IM, Lopez-Camelo JS, et al. 2003. Preliminary data on changes in neural tube defect prevalence rates after folic acid fortification in South America. Am J Med Gen 123A: 123–128.CrossRefGoogle Scholar
  5. Centers for Disease Control and Prevention, 1992. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR 38: 264–267.Google Scholar
  6. Centers for Disease Control and Prevention, 2005. Spina bifida and anencephaly before and after folic acid mandate — United States, 1995–1996 and 1999–2000. MMWR 53: 362–365.Google Scholar
  7. Chambers K, Popkin J, Arnold W, Irwin B, Hall JG, 1994. Neural tube defects in British Columbia. Lancet 343: 489–490.CrossRefGoogle Scholar
  8. Cochrane DD, Wilson RD, Steinbok P, et al. 1996. Prenatal spinal evaluation and functional outcome of patients born with myelomeningocele: Information for improved prenatal counselling and outcome prediction. Fetal Diagn Ther 11: 159–186.CrossRefPubMedGoogle Scholar
  9. Cuckle H, Wald N, 1987. The impact of screening for open neural tube defects in England and Wales. Prenatal Diagnosis 7: 91–99.CrossRefPubMedGoogle Scholar
  10. Czeizel AE, Dudas I, 1992. Prevention of the first occurrence of neural tube defects by periconceptional vitamin supplementation. N Eng J Med 327: 1832–1835.CrossRefGoogle Scholar
  11. De Wals P, Rusen ID, Lee NS, et al. 2003. Trend in prevalence of neural tube defects in Quebec. Birth Defects Research (Part A) 67: 919–923.CrossRefGoogle Scholar
  12. Ethen MK, Canfield MA, 2002. Impact of including elective pregnancy terminations before 20 weeks gestation on the birth defect rates. Teratology 66 (supplement 1): 32–35.CrossRefGoogle Scholar
  13. Feldkamp M, Friedrichs M, Carey JC, 2002. Decreasing prevalence of neural tube defects in Utah, 1985–2000. Teratology 66(supplement 1): 23–28.CrossRefGoogle Scholar
  14. French, Levy-Milne, 2000. Folate intakes and knowledge of women of childbearing age. The status in British Columbia. MSc thesis, Vancouver, UBC, August 2000.Google Scholar
  15. Gallop Organization-March of Dimes, 1997. Preparing for pregnancy II. March of Dimes, Birth Defects Foundation. White Plains, NY.Google Scholar
  16. Gucciardi E, Pietrusiak M-A, Reynolds DL, Rouleau J, 2002. Incidence of neural tube defects in Ontario. 1986–1999. CMAJ 167: 237–240.PubMedGoogle Scholar
  17. Hall JG, Friedman JM, Keena BA, et al. 1988. Clinical genetics and epidemiologic factors in neural tube defects. Am J Hum Genet 43: 827–837.PubMedGoogle Scholar
  18. Health Canada, 2002. Congenital anomalies in Canada — a perinatal health report, 2002. Ottawa: Minister of Public Works and Government Services Canada, Ottawa.Google Scholar
  19. Health Status Registry, 1999. Selected vital statistics and health status indicators. Annual report 1999. Victoria, B.C.: Division of Vital Statistics.Google Scholar
  20. Honein MA, Paulozzi LJ, Mathews TJ, et al. 2001. Impact of folic acid fortification on the US food supply on the occurrence of neural tube defects. JAMA 285: 2981–2986.CrossRefPubMedGoogle Scholar
  21. Lowry B, 2001. Alberta Congenital Anomaly Surveillance System. Fifth Report, 1980–1998. Division of Vital Statistics, Alberta Registries, Edmonton, Alberta.Google Scholar
  22. Mills JL, Rhoads GG, Simpson JL, et al. 1989. The absence of a relation between the periconceptional use of vitamins and neural-tube defects. N Engl J Med 321: 430–435.CrossRefPubMedGoogle Scholar
  23. Mills JL, Signore C, 2004. Neural tube defect rates before and after food fortification with folic acid. Birth Defects Research (Part A) 70: 844–845.CrossRefGoogle Scholar
  24. Morin VI, Mondor M, Wilson RD, 2001. Knowledge on periconceptional use of folic acid in women of British Columbia. Fetal Diagn Ther 16: 111–115.CrossRefPubMedGoogle Scholar
  25. MRC Vitamin Study Research Group, 1991. Prevention of neural tube defects: results of the Medical Research Vitamin Study. Lancet 338: 131–137.CrossRefGoogle Scholar
  26. Oakly GP Jr, 1993. Folic acid preventable spina bifida and anencephaly. JAMA 269: 1292–1293.CrossRefGoogle Scholar
  27. Oakley GP Jr, 2002. Inertia on folic acid fortification: public health malpractice. Teratology 66: 44–54.CrossRefPubMedGoogle Scholar
  28. Oakley GP Jr, Bell KN, Weber MB, 2004. Recommendations for accelerating global action to prevent folic acid-preventable birth defects and other folate-deficiency diseases: Meeting of experts on preventing folic acid-preventable neural tube defects. Birth Defects Research (Part A) 70: 835–837.CrossRefGoogle Scholar
  29. Persad VL, Van den Hoff MC, Dube JM, Zimmer P, 2002. Incidence of open neural tube defects in Nova Scotia after folic acid fortification. CMAJ 167: 241–245.PubMedGoogle Scholar
  30. Roberts HE, Moore CA, Fernhoff PM, Cragan JD, Khoury MJ, 1994. The impact of prenatal diagnosis on the birth prevalence of neural tube defects, Metropolitan Atlanta, 1990–1991. Teratology 49: 386.Google Scholar
  31. Rosano A, Smithells D, Cacciani L, et al. 1999. Time trends in neural tube defects prevalence in relation to preventive strategies: An international study. J Epidemiol Community Health 53: 630–635.CrossRefPubMedGoogle Scholar
  32. State Birth Defects Surveillance Programs Directory, 2002. Neural tube defects (NTDs) rates, 1995–1999. Teratology 66: 59–128.CrossRefGoogle Scholar
  33. Stevenson RE, Allen WP, Pai GS, et al. 2000. Decline in prevalence of neural tube defects in a high-risk region of the United States. Pediatrics 106: 677–682.CrossRefPubMedGoogle Scholar
  34. Van Allen MI, Fraser FC, Dallaire L, et al. 1993. Recommendations on the use of folic acid supplementation to prevent the recurrence of neural tube defects. Can Med Assoc J 149: 1239–1243.Google Scholar
  35. Velie EM, Shaw GM, 1996. Impact of prenatal diagnosis and elective termination on prevalence and risk estimates of neural tube defects in California, 1989–1991. Am J Epidemiol 144: 473–479.PubMedGoogle Scholar
  36. Wilson RD, Van Allen MI, 1993. The use of folic acid for prevention of neural tube defects. J Soc Obstet Gynaecol Can 15 (March suppl): 41–46.Google Scholar
  37. Williams LJ, Mai CT, Edmonds LD, et al. 2002. Prevalence of spina bifida and anencephaly during the transition to mandatory folic acid fortification in the United States. Teratology 66: 33–39.CrossRefPubMedGoogle Scholar

Copyright information

© Institute of Plant Genetics, Polish Academy of Sciences, Poznan 2006

Authors and Affiliations

  • Margot I. Van Allen
    • 1
  • Erin Boyle
    • 1
  • Paul Thiessen
    • 2
  • Deborah McFadden
    • 3
  • Douglas Cochrane
    • 4
  • G. Keith Chambers
    • 5
  • Sylvie Langlois
    • 1
  • Patricia Stathers
    • 1
  • Beverly Irwin
    • 2
  • Elizabeth Cairns
    • 1
  • Patrick MacLeod
    • 6
  • Marie -France Delisle
    • 7
  • Soo -Hong Uh
    • 8
  1. 1.Department of Medical GeneticsChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  2. 2.Department of PediatricsChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  3. 3.Department of PathologyChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  4. 4.Department of SurgeryChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  5. 5.Department of Family MedicineChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  6. 6.Department of Medical GeneticsVictoria General HospitalVictoria
  7. 7.Department of PerinatologyChildren’s and Women’s Health Centre and the University of British ColumbiaVancouver
  8. 8.B.C. Health Status RegistryVictoriaUSA

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