Background Menstrual health (MH) is a public health issue in low- and middle-income countries impacting adolescent girls’ education. This study aims to measure MH self-efficacy and its association with school attendance among girls in Wakiso and Kalungu districts of Uganda.

Methods Participants were Secondary 2 girls enrolled in the ongoing MENISCUS cluster-randomized trial evaluating the impact of a multi-component MH intervention on education, health, and well-being outcomes in 60 secondary schools. Baseline data on demographic and socioeconomic status (SES) was collected through a self-administered questionnaire in March-June 2022. School attendance was measured as a girl missing 2 or more school days during the term due to menstruation, MH self-efficacy was measured using the 26-item Self-efficacy in Addressing Menstrual Needs Scale (SAMNS) with scores categorized into tertiles. Logistic regression was used to assess the association.

Results There were 3,673 girls with a median age of 16 years, of which 2,123 (55.8%) were day scholars, as opposed to boarding students, and 762 (20.0%) were of the lowest SES. The prevalence of missing 2 or more days in term due to menstruation was 830 (22.6%). Missing school due to menstruation was associated with lower SES (OR=1.93, 95%CI: 1.57, 2.36), being a day student (OR 1.53, 95%CI:1.31, 1.70), being older than 15 years (OR = 1.62, 95%CI:1.38, 1.89), and attending government school (OR = 1.27, 95%CI:1.08, 1.49). Missing school for 2 or more days due to menstruation was strongly associated with being in lower menstrual health efficacy after controlling for SES, age, student type (day/boarding), household size, and school ownership (Government/Private) (OR=1.68, 95%CI:1.39, 2.04, P=0.0053).

Conclusion Results indicate that lower MH self-efficacy significantly affects girls’ school attendance. Missing school results in underperformance in the curriculum and decelerates education for the girl child. Supporting these girls through menstruation could improve self-esteem and promote school completion.