Skip directly to search Skip directly to A to Z list Skip directly to site content
CDC Home

QuickStats: Spina Bifida and Anencephaly Rates* --- United States, 1991, 1995, 2000, and 2005

* Per 100,000 live births. Annual data on birth defects are based on information reported on birth certificates provided through the National Vital Statistics System. Because of challenges associated with the reporting of birth defects during the period immediately after birth, spina bifida and anencephaly are considered underreported on birth certificates. Additional information is available at

Excludes data from Maryland, New Mexico, and New York, which did not require reporting for certain years.

§ 95% confidence interval.

Neural tube defects (NTDs) are serious birth defects of the brain (anencephaly) and spine (spina bifida). Since 1992, a national health recommendation has called for women of childbearing age in the United States to consume 400 µg of folic acid daily to reduce their risk for having a pregnancy affected by NTDs. The spina bifida rate per 100,000 live births declined 25% from 1995 to 2000 and 13% from 2000 to 2005. The anencephaly rate declined 36% from 1991 to 1995 and was unchanged from 1995 to 2005.

SOURCE: Mathews TJ. Trends in spina bifida and anencephalus in the United States, 1991--2005. National Vital Statistics System. Available at

Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.

References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

All MMWR HTML versions of articles are electronic conversions from typeset documents. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version ( and/or the original MMWR paper copy for printable versions of official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #