Folic acid consumption reduces the risk for neural tube defects (NTDs).1–3 Significant progress has been made toward the reduction of NTDs since the association with folic acid deficiency was noted; from 1991 to 2001, there was a 23% to 31% decline in NTDs.4 However, preventable NTDs continue to occur. NTDs result from defective neural tube closure and occur during days 22 to 28 of fetal development, before most women are aware of being pregnant or before they have initiated prenatal care.5 Thus, it is recommended that all women capable of becoming pregnant consume at least 400 μg of folic acid daily, regardless of reproductive plans.6
The Food and Drug Administration, in an attempt to passively increase folic acid consumption at the population level, mandated fortification of all enriched grains with folic acid as of 1998. The fortification program is estimated to increase folic acid consumption by an average of 100 to 200 μg per day.7 Thus, the use of folic acid supplements may remain a necessary intervention to reduce the risk of NTDs. Regardless of the source of folic acid, awareness of folic acid benefits will influence adequate consumption and thus affect the occurrence of NTDs.
The March of Dimes in 1995 initiated a “Think Ahead” campaign. This multimedia campaign, which was supplemented with smaller-scale state-based initiatives, aimed to increase folic acid awareness among women of reproductive age. Although studies have noted a discrepancy between folic acid awareness and actual consumption of folic acid,8,9 increased awareness of lifestyle benefits is reported to precede behavior modification.10 Thus, increased folic acid awareness is expected to affect folic acid consumption. In this study, we evaluated the prevalence and trend of folic acid awareness among Michigan women who delivered live births during 1996–1999, and we evaluated maternal characteristics associated with folic acid awareness.
The data for this study were obtained from the Michigan Pregnancy Risk Assessment Monitoring System (PRAMS) during 1996–1999. The institutional review board committees at both the Centers for Disease Control and Prevention and the Michigan Department of Community Health approved the PRAMS study. PRAMS is a population-based survey of women who delivered a live birth in Michigan; it collects information on maternal experiences and health risk behaviors before, during, and shortly after pregnancy.
A stratified random sample of approximately 200 women was selected to participate in the survey each month. The strata in the survey were defined by race (black and nonblack) and birth weight (low [<2500 g] and normal). From recently processed birth certificates, approximately 50 women were selected from nonblack women who delivered low birth weight infants and another 50 from nonblack women who delivered normal birth weight infants. Twenty-five women were selected from black women who delivered low birth weight infants, and another 25 from black women who delivered normal birth weight infants. To improve response rates for urban black women, at five urban hospitals serving predominantly (99%) black women, an additional 25 black women were selected from those who delivered low birth weight infants, and 25 black women were selected from those who delivered normal birth weight infants.
Women selected from the birth certificate files were mailed an advance letter inviting them to participate in the survey, followed by an initial mailing of the full questionnaire. Women selected at hospital discharge were administered an interview in person before discharge to collect demographic and antepartum information. This was followed by an abridged questionnaire (omitting questions already asked during the in-person interview) after they had returned home. For all women, two repeat mailings and telephone follow-up followed the first mailing if a response was not obtained. Data from all questionnaires are also supplemented with information on the birth certificate. The data were then weighted to have similar racial distribution as the entire population of Michigan mothers who delivered a live birth during the year. Additionally, the data were weighted to adjust for nonresponse, omission from the sample, maternal age, education level, and marital status.
This study focused on questions that classify folic acid awareness, as well as on maternal characteristics that may be associated with folic acid awareness: pregnancy planning, race, age, education, parity, timing of prenatal care, and Medicaid enrollment. A positive response to the question, “Before you became pregnant with your new baby, had you heard or read that the vitamin folic acid could help prevent some birth defects?” was used as an indicator of folic acid awareness. Pregnancy planning was evaluated by responses to the question, “When you got pregnant, were you doing anything to prevent a pregnancy?” Women using birth control were categorized as having a contraceptive failure. Women not using birth control were categorized into two groups of their reasons for not using birth control: planned pregnancy (those not using birth control because they desired a pregnancy) and unplanned pregnancy (all others). Women with unplanned pregnancies were considered to be different from those who experienced contraceptive failures; thus, these groups were analyzed separately. Parity and timing of prenatal care were categorized as dichotomous variables for the analysis: primiparous/ multiparous and first/second or more trimester, respectively, and Medicaid enrollment was used as a measure of economic status as well as access to care.
Statistical analysis was performed by SUDAAN 8.0 (Research Triangle Institute, Research Triangle Park, NC) to account for the complex sample design of PRAMS. The outcome variable of interest was folic acid awareness. Logistic regression was used to examine the association between folic acid awareness and the maternal characteristics of interest, and to evaluate the temporal trends in folic acid awareness, overall and in various demographic subgroups. All variables were adjusted for each other in a single multivariable model.
Of the 10,783 women invited to participate in PRAMS during 1996–1999, 7252 women (67.3%) responded. The characteristics of the sample population are listed in Table 1. The first column provides unweighted percentages of the sample population. Approximately half of the sample were black women younger than 25 years of age. Only one-third of the pregnancies were planned, and 80% of the women initiated prenatal care in the first trimester. The second column provides weighted percentages, which reflect the population from which the sample was obtained—women who delivered a live birth in Michigan during the study. All further results are based on these weighted data.
Over the entire study period, 68.5% of the women were aware of folic acid benefits. From 1996 to 1999, folic acid awareness increased overall by 18.5% (60.3–71.4%, P < .001). The largest increase, 20% (60.3–72.1%), occurred during 1996–1997 (Table 2). Since 1997, folic acid awareness overall and in most subgroups remained essentially unchanged; however, folic acid awareness declined in certain subgroups. For example, there was a 77% decline in folic acid awareness among women with no high school education (59.3%–13.8%), which remained statistically significant after controlling for age, race, and income (P = .05). Declines were also observed in other subgroups, including women younger than 25 and those who used birth control at the time of the conception; however, these decreases were not statistically significant after controlling for the variables listed.
We examined folic acid awareness among various sociodemographic subgroups during the study period (Table 2). Compared with women whose pregnancy was planned, those with an unplanned pregnancy (adjusted odds ratio [OR] 0.6; 95% CI 0.5, 0.8) and those whose pregnancy was due to contraceptive failure (adjusted OR 0.74; 95% CI 0.6, 0.8) were less likely to be aware of the benefit of folic acid. In addition, folic acid awareness among black women was significantly lower than women of other racial groups (adjusted OR 0.43; 95% CI 0.4, 0.5). Black women whose pregnancies were planned had an even lower prevalence of folic acid awareness than women of other racial groups with unplanned pregnancies. Further, folic acid awareness among black women remained below 50% during most of the study period. Parity, entry to prenatal care, and Medicaid status were not significantly associated with folic acid awareness.
The substantial increase in folic acid awareness among Michigan women observed in our study is consistent with national data.11 These increases most likely reflect the success of the mid-1990s educational campaigns. Further supporting the effectiveness of education is the association between improved serum folate status and folic acid education during the preconceptional period.12 Despite these increases, we also identified large gaps in folic acid awareness between subgroups of the population, and these gaps have widened during recent years.
Black women were more likely to have a lower prevalence of folic acid awareness, and pregnancy planning does not appear to influence this association. Other studies have shown that black women have benefited less from the folic acid fortification program, experiencing smaller increases in mean blood folate levels after fortification compared with women of other races.13,14 As noted in these studies, disparities in blood folate levels may be the result of cultural and socioeconomic factors that influence access to or acceptance of fortified foods. The disparities may also reflect a lack of education and thus decreased folic acid awareness. Most importantly, this information indicates that black women at risk for decreased folic acid awareness may also be at risk for decreased consumption of fortified foods15 and supports the need to target these groups during educational activities.
The folic acid awareness disparity between women of different educational levels has been documented previously.16,17 The decline in folic acid awareness among women with no high school education in Michigan is particularly important because this group is at higher risk for unplanned pregnancies and adverse pregnancy outcomes.18 In addition, folic acid information is provided in education packets for only 9th to 12th graders in Michigan. Thus, these women have one less exposure to folic acid education. Other important folic acid awareness gaps noted in our study exist among women with unplanned pregnancies. Folic acid awareness declined among women who used birth control at the time of conception, which is important because approximately half of all pregnancies in the United States are unplanned.19
Gaps in folic acid awareness among women with unplanned pregnancies may reflect decreased retention of pregnancy-related education as a result of a perceived lower risk of pregnancy. Moreover, the decline in folic acid awareness may suggest that women who use contraception or those not planning a pregnancy are not receiving adequate folic acid education. If pregnancy planning is the sole trigger for folic acid education and consumption, a substantial proportion of women in the United States stand not to benefit from folic acid consumption, given the early occurrence of NTDs. Thus, all health care encounters, including preventive health visits such as family planning and annual visits, as well as nongynecologic visits and adolescent heath care encounters, should be used to provide folic acid education in an attempt to affect behavior before these women become pregnant.
This study had several limitations. There is potential misclassification of the Medicaid variable. Those who did not receive Medicaid at any time include women without any form of insurance. The potential similarity between this group of women and those receiving Medicaid assistance would result in an underestimation of the association between Medicaid enrollment and folic acid awareness. In addition, this study evaluated awareness and not behavior. Women were not asked about their actual consumption of folic acid. However, as stated previously, awareness is expected to precede behavioral change, and thus declines as well as increases in folic acid awareness may signify potential corresponding changes in consumption. Adding a question to future PRAMS questionnaires that focuses on folic acid consumption (dietary or supplement use) would allow evaluation of changes in consumption and the correlation between awareness and consumption.
The folic acid awareness changes seen in our study are important in supporting the potential effect of education on folic acid awareness and the overall success of this prevention strategy. Education campaigns have been successful in other maternal and child health issues, such as the “Back to Sleep” campaign for reducing the risk of sudden infant death syndrome and the previous campaigns to reduce antenatal smoking. With regards to folic acid awareness and consumption, education is a necessary complement to the fortification program. As mentioned previously, groups at risk for decreased awareness may also be at risk for decreased consumption of fortified foods. In addition, the current fortification levels may not adequately meet recommended daily requirements. Education and increased awareness are expected to improve consumption of fortified foods or dietary supplements. Finally, this study identifies subpopulations that need to be targeted in future educational efforts. The data are being used by the Michigan Birth Defects Program to identify at-risk groups requiring special attention.
Increased participation will be needed by health care providers and community groups to ensure that folic acid information reaches all women of reproductive age. All health care encounters should be used to encourage folic acid consumption. Nontraditional settings for folic acid education, such as school settings, should also be considered.
1. Berry RJ, Li Z, Erickson JD, et al. Prevention of neural-tube defects with folic acid in China: China-US Collaborative Project for Neural Tube Defect Prevention. N Engl J Med 1999;341:1485–90.
2. Czeizel AE, Dudas I. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. N Engl J Med 1992;327:1832–5.
3. Lumley J, Watson L, Watson M, Bower C. Periconceptional supplementation with folate and/or multivitamins for preventing neural tube defects. Cochrane Database Syst Rev 2001;3.
4. Honein MA, Paulozzi LJ, Mathews TJ, Erickson JD, Wong LY. Impact of folic acid fortification of the US food supply on the occurrence of neural tube defects. JAMA 2001;285:2981–6.
5. Locksmith GJ, Duff P. Preventing neural tube defects: The importance of periconceptional folic acid supplements. Obstet Gynecol 1998;91:1027–34.
6. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR Morb Mortal Wkly Rep 1992;41:1–7.
7. Wald NJ, Law MR, Morris JK, Wald DS. Quantifying the effect of folic acid. Lancet 2001;358:2069–73.
8. Sayers GM, Hughes N, Scallan E, Johnson Z. A survey of knowledge and use of folic acid among women of child-bearing age in Dublin. J Public Health Med 1997;19:328–32.
9. Frishman GN, Spurrell TP, Heber WW. Folic acid: Preconception knowledge and use by infertile women. J Reprod Med 2001;46:1025–30.
10. Kloeblen AS, Batish SS. Understanding the intention to permanently follow a high folate diet among a sample of low-income pregnant women according to the Health Belief Model. Health Educ Res 1999;14:327–38.
11. Centers for Disease Control and Prevention. Are women with recent live births aware of the benefits of folic acid? MMWR Morb Mortal Wkly Rep 2001;50:3–14.
12. de Weerd S, Thomas CM, Cikot RJ, Steegers-Theunissen RP, de Boo TM, Steegers EA. Preconception counseling improves folate status of women planning pregnancy. Obstet Gynecol 2002;99:45–50.
13. Folate status in women of childbearing age, by race/ethnicity—United States, 1999–2000. MMWR Morb Mortal Wkly Rep 2002;51:808–10.
14. Than LC, Watkins M, Daniel KL. Serum folate levels among women attending family planning clinics—Georgia, 2000. MMWR Morb Mortal Wkly Rep 2002;51:4–8.
15. Knowledge and use of folic acid among women of reproductive age—Michigan, 1998. MMWR Morb Mortal Wkly Rep 2001;50:185–9.
16. Stepanuk KM, Tolosa JE, Lewis D, et al. Folic acid supplementation use among women who contact a teratology information service. Am J Obstet Gynecol 2002;187:964–7.
17. Perlow JH. Comparative use and knowledge of preconceptional folic acid among Spanish- and English-speaking patient populations in Phoenix and Yuma, Arizona. Am J Obstet Gynecol 2001;184:1263–6.
18. Grimes DA, Raymond EG, Scott Jones B. Emergency contraception over-the-counter: The medical and legal imperatives. Obstet Gynecol 2001;98:151–5.
19. Henshaw SK. Unintended pregnancy in the United States. Fam Plann Perspect 1998;30:24–9,46.