Study On The Implementation Effects And The Influencing Factors Of Neural Tube Defects Intervention Measures

BackgroundNeural tube defects (NTDs) are a group of common and severe birth defects among humans, mainly including the anencephalus, spina bifida and encephalocele. Infants or fetuses with NTDs usually result in miscarriage, dead fetuses, stillbirth and neonatal death, while survivors often suffer from permanent disability, which seriously affects the quality of birth population in China. Currently primary preventive measures of NTDs including folic acid intake, pregnancy planning, health education, genetic counseling and preconceptional examination have been implemented in China and abroad, in order to lower NTDs incidence.Additionally, most cases with NTDs are detected through secondary preventive measures such as antenatal ultrasonography and serological screening. The pregnancy is then terminated to cut down NTDs birth rate and reduce the harm done to these women physically and psychologically as much as possible. However, the effects and influencing factors of the implementation of different prevention measures of NTDs are unclear. How to make every prevention measure more effective is in urgent need of study and exploration.The data from Birth Defects Monitoring Center of China indicates that the NTDs recurrence rate among women who gave birth to infants with NTDs is10to100times of normal women, suggesting that high-risk women who had infants or fetuses with NTDs is the target population of NTDs comprehensive intervention. As researches on NTDs prevention have been done in the general population recently, how to conduct effective comprehensive intervention in high-risk women in order to reduce NTDs recurrence rate is also very important for NTDs intervention.Objective1. To investigate the current implementation of primary prevention of NTDs and evaluate the intervention effects against NTDs; mainly analyze the preventive effects of folic acid intake during different timings by the subjects against NTDs and the influencing factors of intake; and establish Bayesian Network and explore the internal network relationship among the effects of different primary preventive measures and the comprehensive effects on NTDs.2. To investigate the current implementation situation of secondary prevention of NTDs; mainly analyze the implementation effects of ultrasonic examination during the whole pregnancy period among mothers of infants with NTDs, analyze the detection effects and influencing factors of ultrasonic examination and all subtypes: and evaluate the sensitivity and specificity of NTDs serological screening with ultrasonic examination as the diagnostic criteria.3. And to conduct comprehensive knowledge intervention among women who had a pregnancy affected by NTDs and evaluate the intervention effects; know the implementation situation of different preventive measures among NTDs high-risk women and analyze its influencing factors.Methods1.24counties (districts) of Shandong Province and Shanxi Province were used as research sites. A case-control study was conducted as women who had infants or fetuses affected by NTDs within two years before the investigation date were selected as cases, while women who gave birth to healthy infants in the same district, hospital and in the same year were selected as controls. Face-to-face interviews were conducted to investigate the implementation situation of primary preventive measures of NTDs among the subjects as well as their demography characteristics and history, etc.2. Prevalence study was conducted by selecting women who had infants or fetuses with NTDs within two years before the investigation date and by making an epidemiologic investigation based on the prenatal ultrasonic examination and serological screening. The data was collected through face-to-face interviews and consulting medical and health records. 3. Intervention follow-up study was adopted through implementing comprehensive NTDs knowledge intervention among women who had infants or fetuses with NTDs. The contents of intervention included the basic knowledge of NTDs and the implementation methods and effects of different preventive measures. They were followed up one year later to find out their NTDs-related knowledge level and the implementation situation of different preventive measures and influencing factors.4. Data processing and statistical analysis:Database was established using EpiData. Data analysis was conducted using SPSS software and plugin software. Conditional logistic regression model, multivariate logistic regression model, the Bayesian network model, the generalized estimating equation were used for statistical analysis. Effect indicators included:OR, AR%, PAR%; Interaction effect indicators included:RERI, S, AP%.Results1. Primary prevention of NTDs(1) The implementation rates of NTDs primary preventive measures were quite low among the subjects. Periconceptional folic acid intake rate (spanning the fertilization) was11.1%, only5.0%in the case group; pregnancy planning was34.5%, the implementation rates of genetic counseling and preconceptional examination were14.2%and26.6%respectively. Pregnancy planning, health education, genetic counseling and preconcetional examination have remarkable promoting effects on periconceptional folic acid supplementation of women, OR>3.(2) Folic acid intake, pregnancy planning, health education and preconceptional examination have remarkable protective effects on NTDs, OR being0.422,0.581,0.282and0.359respectively. According to univariate analysis, folic acid intake during the periconceptional period (spanning the fertilization) has the greatest preventive effects on NTDs (OR=0.201, P<0.001). The multivariate analysis with other primary preventive measures shows that periconceptional folic acid intake (spanning the fertilization) still has remarkable preventive effects against NTDs (OR=0.165, P<0.001). Folic acid intake and each of the other three primary preventive measures are synergistic, and the synergy indexes are1.331,2.032and1.221respectively.(3) According to Bayesian Network analysis:pregnancy planning can promote the implementation of all NTDs primary preventive measures, making the implementation rates of folic acid intake, health education, genetic counseling and preconceptional examination increase by19.97%,5.24%,7.69%and14.57%respectively. Pregnancy planning and each of the other primary preventive measures have synergistic effects on NTDs prevention, the risk of NTDs decrease by33.68%,28.03%,25.12%and31.62%respectively.2. Secondary prevention of NTDs(1) Ultrasonic examination usage rate of the subjects was98.7%and the general correct diagnosis rate of NTDs was85.9%, the confirmed diagnosis of which was in week24.0of the pregnancy on average. The detection rates in difference medical institutions and in different pregnancy timings and also of the ultrasonography subtypes are low. The detection rate of NTDs before week16of the pregnancy was14.1%and that of week16～20, week20～24, week24～28and beyond week28but including it were49.4%,46.3%,49.2%and52.1%respectively (P<0.05). The detection rates of NTDs in hospitals and maternal and children hospitals were46.4%and52.0%respectively, and that of family-planning departments was28.1%(P<0.05), while the detection rates of black and white ultrasonic examination and two-dimensional ultrasonic examination were36.8%and50.7%(P<0.05).(2) The implementation rate of antenatal serological screening of the subjects was low (7.5%),5.4%in the case group. Antenatal serological screening has protective effects against NTDs (OR=0.457,P<0.01). Based on the NTDs diagnosed by the ultrasonic examination, sensitivity and specificity of NTDs antenatal serological screening were24.0%and97.7%) respectively.(3) According to GEE multivariate analysis:the trimester doing ultrasound examination, the type of medical institutions and ultrasonic types significantly affected the ultrasound detection rate. The ultrasound detection rate in the second and third trimester was significantly higher than that of first trimester, effect value OR were20.147and46.613, respectively (P<0.001). The ultrasound detection rate in Maternal and Child Care Service Centers and hospitals was significantly higher than that of township hospitals (P<0.01),and the OR values were3.411and2.148; There was no significant difference between the ultrasound detection rates of Family Planning Centers and township hospitals (P>0.05). Color Doppler ultrasound detection rate was significantly higher than black and white ultrasound (OR=2.253, P <0.001).3. Knowledge intervention among high-risk women and their pregnancy outcomes(1) When high-risk women had comprehensive NTDs knowledge intervention, their NTDs related knowledge was remarkable improved compared to the situation before and also the control group (P<0.05). After the knowledge intervention in high-risk women, their awareness rate of folic acid intake reached95.5%and the awareness rate of best folic acid intake timing was78.9%, while that of folic acid intake dosage reached77.2%among general women, up by29.5%,67.9%and40.9%respectively than before. The general NTDs intervention knowledge level among high-risk women was remarkably improved, the general score much higher than before and the control group, but still with a low proportion of the highest score (≥10points), no less than20%.(2)132high-risk women had a subsequent pregnancy after the knowledge intervention, during which the implementation rate of primary prevention of NTDs increased remarkably (P<0.05). Folic acid intake rate increased by53.8%, from25.0%to78.8%, and the intake rate at the best timing (periconceptional period spanning the fertilization) was still below20%. Thus,21.2%of high-risk women did not take folic acid while63.3%of women did not take it at the best timing. Besides, pregnancy planning increased from35.2%to67.4%. Pregnancy planning increased the periconceptional folic acid intake rate remarkably, by10.646times (P<0.001). (3) Among the132high-risk women who had a subsequent pregnancy, there were4NTDs recurrent cases, of which one was missed diagnosis through ultrasonic examination, and three were confirmed diagnosis, with the average diagnosis time confirmed in pregnancy week24.7and three examinations on average. Besides, one cheilopalatoschisis case, one strephenopodia case and one microphthalmia case failed to be confirmed by ultrasonic examination. The diagnosis of recurrent NTDs case was still confirmed later than the best timing. In addition, the implementation rate of antenatal serological screening was low among the high-risk women (21.2%). The four mothers who again had NTDs infants had no serological screening during this pregnancy.Conclusion1. The implementation rate of primary prevention of NTDs was low among subjects, especially periconceptional folic acid intake rate and genetic counseling rate below20%. Multiple methods should be adopted to further popularize and promote NTDs intervention knowledge among women of child-bearing age.2. Folic acid intake, pregnancy planning, health education and preconceptional examination all had preventive effects against NTDs among the subjects. Folic acid intake during the periconceptional period (the best timing) had the strongest preventive effects on NTDs. Therefore, vigorous promoting of continuous folic acid intake during the periconceptional period (three months before fertilization and three months after that) has great significance in improving folic acid prevention effects against NTDs.3. Pregnancy planning is an important precondition for the promotion and implementation of all preventive measures of NTDs, which can increase the preventive effects of NTDs of different measures.70%of subjects in this study had unplanned pregnancy (accidental pregnancy), which indicates that improving planned pregnancy rate among women of child-bearing age is key to prevention of NTDs in China.4. Ultrasonic examination is the most important measure of secondary prevention of NTDs. However, the current detection rates of NTDs through ultrasonic examination and the subtypes are low with ineffective results. The average diagnosis timing was three weeks behind that of developed countries. Related medical departments should take measures to further improve the implementation rate of ultrasonic examination as well as its diagnosis rate of NTDs, attach more importance to the ultrasonic examination in basic-level medical institutions and better bring the ultrasonic examination into play in NTDs secondary prevention.5. As a NTDs secondary preventive measure, antenatal serological screening has a low implementation rate, low sensitivity and high missed diagnosis rate. So far, serological screening has not had the expected NTDs screening effects.6. Knowledge intervention before pregnancy can improve the NTDs-related knowledge level among high-risk women and promote the implementation of NTDs preventive measures among high-risk women. Therefore, related birth health institutions should have intensive NTDs intervention knowledge popularization for high-risk women before pregnancy regularly.7. After the knowledge intervention, periconceptional folic acid intake is still low among high-risk women. Planned pregnancy is a key factor to its promotion, which should be given enough attention during NTDs intervention for high-risk women.8. In this study, the recurrence rate of NTDs in high-risk women was3.03%. Among high-risk women, the current implementation situation and effects of preventive measures of NTDs were not very good. Related medical institutions should take measures to further improve the implementation effects of these measures among high-risk women.