Long-acting reversible contraception, condom use and sexually transmitted infections in developing countries: a multi-country serial cross-sectional analysis using demographic and health surveys.

Abstract

INTRODUCTION: Unintended pregnancy and sexually transmitted infections (STIs) are major public health issues in developing countries. While long-acting reversible contraception (LARC) effectively prevents unintended pregnancy, there is limited evidence from large multinational studies on its association with condom use and STI-related outcomes. This study aimed to investigate the association between LARC use, condom use and STIs among women in developing countries. METHODS: This serial cross-sectional study extracted data from Demographic and Health Surveys (DHS), a series of nationally representative household surveys conducted in developing countries. The analysis included women aged 15 to 49 years, with data on contraceptive methods and demographics. Generalised linear mixed effect models (GLMMs) were used to estimate adjusted prevalence ratios (aPRs) for condom use and self-reported STI-related outcomes, comparing LARC users with both non-LARC users and oral contraceptive users. Subgroup analyses were conducted at the individual level and at the country level. RESULTS: Data from 2 171 884 women across 31 countries were analysed. Overall, the prevalence of self-reported STI-related outcomes was 7.4%, 3.9% of participants used LARC, and 7.5% of participants reported consistent condom use. LARC users were significantly less likely to use condoms compared with non-LARC users (aPR=0.40, 95% CI 0.30 to 0.53) and compared with oral contraceptive users (aPR=0.61, 95% CI 0.48 to 0.78). LARC use was associated with a higher prevalence of STI-related outcomes compared with non-LARC users (aPR=1.19, 95% CI 1.10 to 1.28) and compared with oral contraceptives users (aPR=1.14, 95% CI 1.05 to 1.24). Associations were stronger in low-Human Development Index (HDI) countries, especially among younger women (15-19 years), but were not significant in high-HDI countries. Country-level heterogeneity was observed. CONCLUSIONS: LARC use is associated with reduced condom use and higher self-reported STI prevalence, particularly among younger women and in lower HDI developing countries. These findings support integrating STI prevention into LARC services and promoting dual-method use to prevent both unintended pregnancies and STIs.