A Study On The Effects Of Folic Acid Supplements For Neural Tube Defects Prevention And Influencing Factors On It

A study on the effects of folic acid supplements for Neural Tube Defects prevention and influencing factors on itBackground:Neural tube defects (NTDs) are congenital structural abnormalities of the brain and the vertebral column which including spina bifida, anencephaly and encephalocele. Most cases of NTDs are prenatally diagnose, often leading to termination of a wanted pregnancy, and each diagnosis of a neural tube defect is a tragedy for a family, especially for mothers who are suffered from not only the physical but the mental. Fortunately, the protective effect of folic acid against NTDs has been convincingly demonstrated in many trails, and the protective rate (PR) is about 50%-80%. However, programs implemented to date by fewer than 40 countries have prevented only 10% of the estimated 240,000 annual cases of folic acid-preventable spinal bifida and anencephaly. In China, the rate of folic acid for childbearing women is below 15%. So, the actual result which we obtained was far from the expected from the programs of folic acid supplement promotion.Objectives:To explore the effects of folic acid supplements for NTDs prevention, to analyze the influencing factors on using folic acid supplements, and then obtain the effective ways in improving the effects of NTDs prevention.Methods:(1) 1:1 case-control study based on the hospitals was implemented from March to December,2008. Women who had delivery NTDs within 2 years in 20 districts in Shandong and Shanxi province (case group) were interviewed by the investigators face to face. The control group was from the same district, same hospital and same delivery time as the case group, where the women delivered healthy baby.(2) A cross sectional study was conducted. Two counties were chosen by two-stage random sampling from two regions in Shandong Province, the Maternal and Child Health hospital in each county was the study field. The childbearing age women, in the hospitals, were the subjects from January to February in 2008.Results:(1) The rates of folic acid intake were 30.7% and 50.3% in case and control group(P<0.001).The Conditional logistic regression analysis indicated that taking folic acid was the protective factor for NTDs prevention (OR=0.439,95%CI: 0.301-0.641,P<0.001). Further analysis showed that there were different protective effects among different time during pregnancy, especially for periconceptional period (92%).(2) Women who were aware of folic acid (OR=13.266,95%CI:7.358～23.917), planned pregnancy (OR=2.081,95%CI:1.432～3.026) were more likely to take folic acid supplement during pregnancy. For the awareness of folic acid, AR% and ARP% were 92.5% and 86.1%, and for the pregnancy planning, they were 51.9% and 27.2% respectively. Further analysis showed these two facts played important part in taking folic acid at different period. The interaction among the protective factors were estimated, the results showed that there was a positive interaction between the awareness of folic acid and pregnancy planning\health education\pre-pregnant health examination on additive model (RERI:16.42,12.62,14.01).(3) The rates of women who never took folic acid were 69.3% and 49.7%. In the different periods, the rates of folic acid were different. Only 4.6% of women had taken folic acid during periconceptional period, and case and control group were 1.5% and 7.6%. The rates of folic acid for case and control group at pre-conception were 3.9% and 5.9%, and 25.3% and 36.8% at post-conception. There were different significances of use of folic acid supplements at pre-conception and post-conception between case and control group (P<0.001).(4) The rate of awareness of folic acid should be improved at present. Among the women of child bearing age,37.6% knew about the protective effect of folic acid against NTDs, although 60% reported that they were aware of folic acid.36.6% of women knew the advised time to take it, but only 5.8% knew the advised dose to take. Among female college students,53.1% of students were aware of folic acid, and 25.8% of them knew the protective effects of folic acid. For these girls, the rates of awareness of the advised time and the advised dose to take were 4.0% and 6.3% respectively.(5) The awareness of the effect of folic acid was more significant among women with higher education, pregnant history or with health education. The childbearing age women with higher education, pregnancy history and health education were more likely to be aware of folic acid(P≤0.01). The students who majored in medicine, postgraduate student or had received health education were more likely to know the information on folic acid (P<0.005).Conclusions:(1) It is effective for women to take folic acid for NTDs prevention (56%) in this study, especially during periconceptional period (92%).(2) Awareness of folic acid and planning pregnancy play importants role in folic acid intake for women of child bearing age, and these two factors have interaction effect(OR=39.05). It could be applied into the practice for folic acid supplement recommendation.(3) The rate of intake and awareness of folic acid should be improved at present (40%), especially the exact information related folic acid and NTDs.(4) For the college students, it is necessary to tell them the information on NTDs prevention by health education.