Key Findings: Folic acid use among pregnant women who have had a past pregnancy affected by a neural tube defect

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CDC’s Morbidity and Mortality Weekly Report has published a new study looking at folic acid use before pregnancy in women who have had a previous pregnancy affected by a neural tube defect (NTD). CDC researchers found that among a group of pregnant women who had a previous pregnancy affected by an NTD, women with another pregnancy affected by an NTD reported taking folic acid less often (35%) than those who had a baby without a birth defect (80%). This is important information for healthcare providers and health departments because many women who have had a pregnancy affected by an NTD and are planning a next pregnancy may not be following folic acid recommendations. You can read the article here.

Main Findings

  • This study looked at women who had a previous pregnancy affected by an NTD. During their next pregnancy, women who had their subsequent pregnancy affected by an NTD were less likely to have taken folic acid (35% took folic acid) compared with women who had a subsequent baby without a birth defect (80% took folic acid).
  • More than one third of the mothers who had a second pregnancy affected by an NTD were Hispanic.
  • Healthcare providers and health departments should strengthen their messages to encourage folic acid use among women with a previous pregnancy affected by an NTD who are planning another pregnancy.
Pregnant woman taking folic acid

About this Study

  • Researchers used data from the National Birth Defects Prevention Study for the years 1997-2009. They looked at mothers who had a previous pregnancy affected by an NTD and explored maternal characteristics for those who did and those who did not have another pregnancy affected by an NTD.
  • Researchers studied a number of factors about mothers including:
    • Type of NTD (anencephaly, spina bifida, and encephalocele) that occurred in her previous affected pregnancy
    • Folic acid supplement use in the 3 months before pregnancy
    • Race/ethnicity
    • Body mass index (BMI)
    • Prescription medication use
    • Pregnancy intention (whether a woman had planned the pregnancy)

Neural Tube Defects: CDC activities

CDC is working to address neural tube defects with the following activities:

  • Tracking: CDC funds and coordinates the Metropolitan Atlanta Congenital Defects Program (MACDP). CDC also funds 14 population-based state tracking programs. Birth defects tracking systems are vital to help us find out where and when birth defects, like anencephaly and spina bifida, occur and whom they affect.
  • Research: CDC funds the Centers for Birth Defects Research and Prevention, which collaborate on large studies such as the National Birth Defects Prevention Study (births 1997-2011) and the Birth Defects Study To Evaluate Pregnancy exposureS (started with births in 2014). These studies work to identify factors that increase or decrease the risk for birth defects, including neural tube defects.
  • Prevention efforts: Compared to non-Hispanic white and black women, Hispanic- or Latina – women have the highest rate of having a child affected by neural tube defects (2) This could be because they have lower blood folate levels and they are less likely to take vitamins containing folic acid (3-7). CDC recently released a report that showed that fortifying corn masa flour with folic acid could increase the intake of folic acid among some groups of Hispanic women in the United States, specifically Mexican American women and those who have not adopted common social features or habits, such as diets, common in the United States (8).
Basics about NTD Recurrence
  • NTD recurrence is when a woman who already had a pregnancy affected by an NTD has another pregnancy affected by an NTD.
  • Women with a previous pregnancy affected by an NTD are more likely to have another pregnancy affected by an NTD.
  • Taking high-dose folic acid before another pregnancy reduces this risk.
  • If these women are planning another pregnancy, CDC recommends they consume high-dose folic acid (4.0 mg) beginning at least 4 weeks before becoming pregnant and continuing through the first 12 weeks of pregnancy1.
  • High-dose folic acid supplements require a prescription by a healthcare provider.

More Information

To learn more about folic acid, please visit

https://www.cdc.gov/ncbddd/folicacid/index.html

Key Findings Reference

CDC. Supplement Use and Other Characteristics among Pregnant Women with a Previous Pregnancy Affected by a Neural Tube Defect—United States, 1997-2009. MMWR Morb Mortal Wkly Rep. 2015: 64(01);6-9.

Additional References

  1. CDC. Use of folic acid for prevention of spina bifida and other neural tube defects–1983-1991. MMWR Morb Mortal Wkly Rep 1991;40:513-6.
  2. Boulet SL, Yang Q, Mai C, et al. Trends in the postfortification prevalence of spina bifida and anencephaly in the United States. Birth Defects Res A Clin Mol Teratol. 2008;82(7):527-32.
  3. CDC. Racial/ethnic differences in the birth prevalence of spina bifida – United States, 1995-2005. MMWR Morb Mortal Wkly Rep. 2009;57(53):1409-13.
  4. CDC. Folate status in women of childbearing age, by race/ethnicity – United States, 1999-2000. MMWR Morb Mortal Wkly Rep. 2002;51(36):808-10.
  5. CDC. Are women with recent live births aware of the benefits of folic acid? MMWR Morb Mortal Wkly Rep. 2001;50(RR06):3-14.
  6. Pfeiffer CM, Hughes JP, Lacher DA, et al. Estimation of trends in serum and RBC folate in the U.S. population from pre- to postfortification using assay-adjusted data from the NHANES 1988-2010. J Nutr. 2012;142(5):886-93.
  7. Hamner HC, Mulinare J, Cogswell ME, et al. Predicted contribution of folic acid fortification of corn masa flour to the usual folic acid intake for the US population: National Health and Nutrition Examination Survey 2001-2004. Am J Clin Nutr. 2009;89(1):305-15.
  8. Hamner HC, Tinker SC, Flores AL, Mulinare J, Weakland AP, and Dowling NF. Modelling fortification of corn masa flour with folic acid and the potential impact on Mexican-American women with lower acculturation. Public Health Nutr. 2013;16(5):912-21.