OBJECTIVE To clarify the fetal safety of herbal Kampo medicines, including Hange-koboku-to, Koso-san, Nyoshin-san, Yokukansan, Yokukansan-kachinpi-hange, Saiko-keishikankyo-to, Keishi-karyukotu-borei-to, and Kanbaku-taisou-to, when administered to pregnant women with depression using a large healthcare administrative database. METHODS We extracted data from the JMDC Claims Database (2005-2018) for this retrospective cohort study of pregnant women aged 19 years or older admitted to obstetric clinics or hospitals for delivery. Participants were classified into four groups: those without depression, those diagnosed with depression without medication, those given Kampo medicines for depression, and those given western medicines for depression. Neonatal outcomes (congenital anomalies, low birth weight, and preterm birth) were considered as the safety outcome measures. RESULTS We identified 179 707 eligible mothers. The adverse outcomes did not differ significantly between participants receiving Kampo medicine and those not diagnosed with depression during pregnancy. The proportion of low-birth-weight neonates did not differ significantly between the Kampo medicine and non-depression groups (adjusted odds ratio [aOR] 1.28; 95% confidence interval [CI] 0.86-1.91), but was significantly higher in the unmedicated depression group (aOR 1.31; 95% CI 1.07-1.61) and western medicine group (aOR 1.47; 95% CI 1.18-1.83). CONCLUSIONS Kampo medicines are safe for treating depression during pregnancy without increasing the incidence of congenital anomalies, low birth weight, or preterm birth.