Background and Objectives: Maternal brain tumors diagnosed during pregnancy are very rare, and their clinical course remains incompletely understood. We recently experienced a case of a brain tumor diagnosed at 30 weeks of gestation, and the treatment was initiated after delivery at 32 weeks of gestation. In this study, we reviewed case reports of brain tumors diagnosed during pregnancy, focusing on whether the brain tumor was treated during pregnancy or after termination of pregnancy and on the timing of therapeutic intervention. Materials and Methods: We searched PubMed and Ichushi-Web for articles published after January 2000 that reported cases of maternal brain tumors diagnosed during pregnancy. The patients were divided into two groups according to whether the tumor was treated during pregnancy (Group A) or after termination of pregnancy (Group B). Results: In total, 42 patients were included in the study (13 (31%) in Group A and 29 (69%) in Group B). The most common symptoms before diagnosis were those caused by increased intracranial pressure (57.1%). The diagnosis was made at 18 ± 6 weeks of gestation in Group A and 26 ± 9 weeks of gestation in Group B (p = 0.007). In all cases diagnosed after 34 weeks of gestation, termination of pregnancy was followed by treatment. Treatment was initiated within two weeks of diagnosis in 50% of patients in Group A and 30% in Group B. Conclusions: When severe symptoms caused by increased intracranial pressure last for several weeks, imaging tests should be considered. Termination of pregnancy is a good option for a brain tumor diagnosed after 34 weeks of gestation, while comprehensive treatment decisions should be made based on the severity of symptoms and the course of pregnancy in other cases.