Tehran University of Medical Sciences Journal of Biostatistics and Epidemiology 2383-4196 10 3 2024 12 15 281 310 Farzad Khodamoradi Department of Biostatistics and Epidemiology, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Maedeh Arshadi 1 Department of Epidemiology and Biostatistics, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Fateme Shakeri Shamsi 2 Center for Healthcare Data Modeling, Departments of Biostatistics and Epidemiology, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Zahra Beygi Beygi 1 Department of Epidemiology and Biostatistics, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Fateme Ebrahimi Department of Epidemiology and Biostatistics, School of Public Health, Esfahan University of Medical Sciences, Esfahan, Iran. Hosein Azizi Women's Reproductive Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Shahriyar Ghanbarzadeh javid 5 Research Center of Psychiatry and Behavioral Sciences, Tabriz University of Medical Sciences, Tabriz, Iran 2024 03 16 2024 12 28 Introduction: Limited studies have been conducted on the effect of oral contraceptive pills on the subgroups of ovarian cancer, so we decided that conduct a systematic review and meta-analysis to investigate the effect of preventive pills on ovarian cancer subgroups. methods: Scopus, PubMed, Web of Science and EMBASE were searched to identify studies on the association between OCPs and subtypes of ovarian cancer from January 1, 2000, through February 5, 2023. The pooled relative risk (RR) and odds ratio (OR) were used to measure this relationship. Results: A total of 48 studies were included. In the association between ever-use compared with never-use of OCPs and ovarian cancer risk, the pooled RR in cohort studies was 0.69 [95% CI: 0.61, 0.78], and the pooled OR of the case-control studies was 0.64 [95% CI: 0.59, 0.69]. For the relationship between OCPs and subtypes of ovarian cancer, there is a significant inverse relationship between OCPs and serous 0.72 [95% CI: 0.23, 0.82] and endometrioid 0.74 [95% CI: 0.64, 0.86], but no association between OCPs and clear cell 0.84 [95% CI: 0.60, 1.16] and mucinous 0.80 [95% CI: 0.63, 1.01]. Conclusions: This study shows a statistically significant inverse relationship between ever-use compared to never-use of OCPs and ovarian cancer risk. Also shows a statistically significant inverse relationship between serous and endometrioid cancer and OCPs, but no association between OCPs and clear cell and mucinous. https://jbe.tums.ac.ir/index.php/jbe/article/view/1397