This systematic review and meta-analysis evaluated the safety of montelukast in treating asthma during pregnancy, focusing on maternal and fetal outcomes such as congenital anomalies (CA), preterm delivery, low birthweight, spontaneous abortion, gestational diabetes mellitus, and preeclampsia. A comprehensive literature search was conducted in Google Scholar, PubMed, and the Cochrane Library databases from inception until April 30, 2024. The eligible studies assessed the safety of montelukast for asthma treatment during pregnancy. The review suggests that montelukast use during pregnancy may not significantly increase the risk of major CA. The pooled results yielded risk ratio (RR) for CA was 1.13 [95% CI (0.74, 1.73), p = 0.56, I = 0%]. Montelukast may be associated with preterm delivery and a low birthweight odds ratio (OR) of 1.82 [95% CI (1.35, 2.45), p < 0.001, I = 0%]. No significant risks were found concerning neurodevelopmental outcomes. The associations with spontaneous abortion were inconclusive [OR = 1.03, 95% CI (0.72, 1.5), p = 0.86, I = 73%], highlighting the need for further research. This comprehensive review underscores the importance of further investigating the safety profile of montelukast during pregnancy. While the overall findings indicate a relatively favorable safety profile, especially regarding major CA, careful consideration is needed for the potential risks of preterm delivery and low birthweight.© 2024 Japanese Teratology Society.