Introduction China is among the high incidence countries for neural tube defects (NTDs) and great efforts have been made towards their prevention. This study is to understand the effects and influencing factors on prevention measures.

Methods A matched case-control study and prevalence studies were employed. 459 women who gestated babies/foetuses with NTDs and their controls were selected and investigated in 24 districts of two provinces in China. Logistic regression models and interaction analysis was used for data analysis.

Results Folic acid supplementation, planned pregnancy, preconception examination and health education were associated with reduced NTDs (ORs 0.52, 0.27, 0.48 and 0.36 respectively). The folic acid supplementation rate was 5.0% of cases and 17.2% of controls. Folic acid supplementation showed synergistic interaction effects with the other primary prevention measures and prevention rates were 93%, 89% and 90% respectively. 85.9% of the NTDs were diagnosed by ultrasound screening on average at 24.0 weeks gestation. The detection rates by ultrasonography before 16, 16–20, 20–24, 24–28 and after 28 weeks were 14.1%, 49.4%, 46.3%, 49.2% and 52.1% respectively (p<0.05). The detection rates were 46.4%, 52.0% and 28.1% in hospitals, maternal and child care service centres and family planning centres respectively (p<0.05).

Conclusion Folic acid supplementation rate was low in the study subjects. Its use is correlated with planned pregnancy, preconception examination and health education. The efficiency of ultrasonography for NTDs screening could be improved in medical reproduction health institutions.