Background: Contraceptive agents are widely used by women of reproductive age, and resulting depression is the most common side effect of this usage. This study aimed to study the effect of monthly injectable combined contraceptives versus that of combined oral contraceptive pills (COC) on patients’ mood. Methods: A prospective cohort study was conducted on 124 females aged 18–45 years attending the Kom-Ashfeen Family Medicine Unit, El-Kalyubia, Egypt. Participants were divided into three groups according to their choice: group A included 44 participants who received monthly combined injectable contraceptives (CIC); group B included 40 participants who took COC; and group C included 40 participants who used the copper intrauterine device (IUD). The Patient Health Questionnaire-9 (PHQ-9) score was assessed at the beginning of the study and after 6 months of follow-up. Results: After 6 months of follow-up, there were mild but statistically significant increases in the PHQ-9 score in groups A and B, with group A (CIC users) showing the highest increase. Approximately 34.1%, 27.5%, and 15% of CIC, COC, and IUD users, respectively, moved from the non-depression stage to mild depression after 6 months; this change was statistically significant in groups A and B only. Conclusion Monthly injectable combined contraceptives and oral contraceptive pills were associated with an increased risk of developing mild depression; this risk was higher in users of CICs, although the difference was not statistically significant. Thus, it is crucial to counsel patients about this possible risk and to follow them up. However, further studies are required to confirm our results.