Baseline characteristics of WWE
Baseline characteristics of WWE in the planned and unplanned pregnancy group are summarized in Table 1. WWE in the planned group had a younger age of seizure onset (16 [12-20]) than the unplanned-pregnancy group (18 [13-22]; P = 0.016). There were no significant differences in the age at conception (P = 0.173, Mann–Whitney U test) and types of epilepsy (P = 0.479, Chi-square test) between the two groups. The unplanned-pregnancy group tended to have a higher proportion living in rural areas compared with that of the planned group (64.4% vs 56.4%; P = 0.081, Chi-square test). As expected, of the two groups, the unplanned-pregnancy group had a lower education level (P = 0.003, Chi-square test), with 1.7% illiteracy and 17.6% primary school education; in the planned group, no one was illiterate, and 91.5% of the cases of pregnancy received a middle school education or above. Folic acid supplementation patterns were significantly different (P < 0.001, Chi-square test) between the planned and unplanned pregnancy groups: 39.8% in the unplanned group did not take folic acid supplementation during pregnancy, and 24.2% received inappropriate folic acid supplementation. By contrast, 100% in the planned group took folic acid supplementation, and 81.9% received appropriate folic acid supplementation.