Objective: The package inserts are official clinical decision-making documents that provide pharmacological treatment information. However, it has been noted that package inserts on perinatal drug usage differ greatly from expert opinions. This study identified Japanese package insert drugs that are contraindicated for pregnant women and compared them to foreign risk categories.Methods: The survey included 19,022 drugs on the drug pricing list as of April 2022, with package inserts available on the Pharmaceuticals and Medical Devices Agency website. We retrieved the package inserts with the word “pregnant” in the “Contraindications” section and reviewed the descriptions to exclude those that satisfied the exclusion criteria. We also checked the foreign risk categories of contraindicated ingredients for pregnant women. This study used the Australian Therapeutic Goods Administration’s categorization for prescribing medicines in pregnancy (the TGA classification).Results: Of the 19,022 medicines studied, 4,111 (21.6%) were contraindicated for pregnant women. Conversely, 19 (5.1%) ingredients categorized under the relatively safe TGA classifications A, B1, and B2 were also contraindicated for pregnant Japanese women.Conclusion: This study revealed that Japanese package inserts contraindicate over 20% of drugs for pregnant women. On the other hand, some forbidden ingredients did not match the foreign risk categories. Therefore, healthcare professionals should be aware of the limitations of Japanese package inserts concerning pregnant women and make careful decisions based on both package inserts and additional drug information.