Prevalence and trend of neural tube defects in five counties in Shanxi province of Northern China, 2000 to 2014.

BACKGROUND

The prevalence of neural tube defects (NTDs) in northern China is among the highest in the world. A massive folic acid supplementation program as a specific countermeasure was introduced in 2009. Examining trends in NTD prevalence may provide evidence for future intervention.

METHODS

Data for 2000 to 2014 in five counties in northern China were obtained through a population-based birth defects surveillance system. All live births, stillbirths of over 20 gestational weeks, and pregnancy terminations because of NTDs at any gestational age were recorded. The prevalence of NTDs by gestational weeks (< 28 vs. ≥ 28), by calendar year, and by subtype was presented.

RESULTS

From 2000 to 2014, a total of 234,225 births and 2027 cases of NTDs were recorded. The prevalence of total NTDs was extremely high during 2000 to 2004, but it began to decrease continuously thereafter, from a peak of 120.0/10,000 in 2004 to a low of 31.5/10,000 in 2014. A significant decrease (60%) was observed from 78.8/10,000 in 2009 to 31.5/10,000 in 2014, 5 years after the folic acid supplementation program was introduced. All three major subtypes, namely anencephaly, spina bifida, and encephalocele, showed a decline over this period. Although the perinatal (≥ 28 gestational weeks) prevalence of NTDs decreased progressively, the pre-perinatal (< 28 gestational weeks) prevalence of NTDs remained high until 2011 and then decreased.

CONCLUSION

The prevalence of NTDs remains high despite a substantial and continuous decrease over the past 15 years. To further reduce NTD risk in the population, fortification staples with folic acid should be considered.