Original Article
Long Term Maintenance of Neural Tube Defects Prevention in a High Prevalence State

https://doi.org/10.1016/j.jpeds.2010.12.037Get rights and content

Objective

To assess the efficacy of folic acid (FA) supplementation and fortification in preventing neural tube defects (NTDs) in a high prevalence region of the United States.

Study design

Active and passive surveillance methods were used to identify all fetuses/infants affected with an NTD in South Carolina. Prevalence rates were compared with FA intake to determine the effects of increased intake on NTD occurrence and recurrence.

Results

From 1992 to 2009, 916 NTD cases occurred in South Carolina, with isolated defects comprising 79% of cases. The NTD rate decreased 58% during this period. There was one NTD-affected pregnancy in 418 subsequent pregnancies (0.2%) in mothers with earlier NTD-affected pregnancies who consumed periconceptional FA supplements, and there were 4 NTDs in 66 pregnancies (6.1%) in which the mother did not take FA supplements. FA supplementation increased from 8% to 35% from 1992 to 2007, and knowledge of the protective benefits of FA increased from 8% to 65% in women of childbearing age.

Conclusions

Increased periconceptional intake of FA appeared to reduce NTDs in a high-prevalence region. The rate of spina bifida and anencephaly in South Carolina is now essentially the same (0.69 cases per 1000 live births and fetal deaths) as the 1998 to 2005 US rate (0.69).

Section snippets

Methods

Neural tube defects were defined as cases of spina bifida, anencephaly, and encephalocele.1 Midline cranial aplasia cutis congenita and multiple vertebral malformations were included as forme fruste NTDs. Isolated NTDs had no significant anomalies in other organ systems. Hydrocephaly and club feet were considered secondary consequences of NTDs. Abdominal wall defects, diaphragmatic hernia, and holoprosencephaly were considered non-related malformations for purposes of this study.

Both active and

Results

The annual prevalence rates for the 17 years of surveillance are shown in Table I, with a graphic representation of the rates of isolated NTDs, NTDs with other anomalies, and total NTDs for years 1 to 17 (Figure 1). There were statistically significant declines in overall NTDs (P < .0001) and in isolated NTDs (P < .0001), but not for NTDs with associated anomalies (P = .2803) from 1992 through 2009. Table I also shows the rates of spina bifida, anencephaly, and encephalocele for 17 years of

Discussion

A substantial decrease in the prevalence rates of spina bifida, anencephaly, and encephalocele in South Carolina has accompanied the increased consumption of FA by women of childbearing age. Overall, the NTD rate has decreased 58% since 1992, a period during which FA supplement use has increased 4-fold (from 8% to 35% of women of childbearing age). In addition, many breakfast cereals have been fortified with 400 mcg FA per serving, and enriched cereal grain flours have been fortified with 140

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    Supported by the South Carolina Birth Defects Foundation, South Carolina Department of Disabilities and Special Needs, South Carolina Department of Health and Environmental Control, South Carolina Department of Health and Human Services, the Developmental Disabilities Council of the Governor’s Office, South Carolina Chapter of the March of Dimes, Centers for Disease Control and Prevention (U85/CCU 408774, U50/CCU 421871, and U50/CCU 416008 to R.S.), and the National Institute of Mental Health (MH 57840 to R.S.). The authors declare no conflicts of interest.

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