To examine the association of the combination of taking neuropsychiatric medications from the onset of pregnancy to mid-pregnancy and maternal psychological distress at mid-pregnancy, with children's behavioral problems. Neuropsychiatric medication use from the onset of pregnancy to mid-pregnancy was defined by the self-reported name of the neuropsychiatric medication in the questionnaire in early and mid-pregnancy. Maternal psychological distress was defined by the Kessler Psychological Distress Scale (K6) ≥13 on the questionnaire in mid-pregnancy. We classified the participants into four categories based on the combination of taking neuropsychiatric medications and psychological distress: "None," "Medications only," "K6 ≥ 13 only," and "Both." Children's behavioral problems were assessed using the Child Behavior Checklist for Ages 1½-5 (CBCL) at 2 years of age. The clinical ranges of the internalizing and externalizing scales of the CBCL were defined as behavioral problems. We conducted a multivariable logistic regression analysis to examine the associations between the four categories of maternal exposure and children's behavioral problems. Compared with the "None" category (n = 9873), the "K6 ≥ 13 only" category (n = 308) was statistically significantly associated with internalizing and externalizing problems. In contrast, the "Medications only" (n = 93) and "Both" (n = 22) categories were not statistically significantly associated with internalizing and externalizing problems, although the point estimates of the odds ratio in the "Both" category were relatively high (1.58 for the internalizing problem and 2.50 for the externalizing problem). The category of mothers taking neuropsychiatric medications and having no psychological distress during pregnancy was not associated with children's behavioral problems in the present population.