Background: This thesis examines the complex relationship between fertility intentions, contraception, and fertility in northern Malawi. Malawi has one of the highest contraceptive prevalence rates (CPR) in sub-Saharan Africa (42%), puzzlingly coupled with one of the highest fertility rates (5.7)[1]. Conventional assessments of contraception do not furnish a clear understanding of contraceptive dynamics. The Karonga Prevention Study (KPS) provides a unique opportunity to unpack these issues. Methods: A secondary data analysis was conducted to explore whether rates of conception varied by fertility intentions and contraceptive use in Karonga. A new one-year prospective longitudinal study collected provider-recorded data on contraceptive services, using patient-held records for 4,678 women aged 15-49, allowing an exploration of postpartum uptake, contraceptive switching and discontinuation. In-depth interviews explored women’s reasons for contraceptive choices and changes. Findings: Women who wanted a child within two years had a 45.5% chance of conceiving within two years, as compared to an 11.7% chance for women who wanted no more children. A novel construct of the CPR was used (the “actual CPR”) and estimated at 35.1%. There was high discontinuation of injectables and oral contraception pills (OCP) (only 51.2% of injection-users and 27.9% of OCP-users had their next injection/pill-cycle on time), and just 15.1% managed to adhere to the injection schedule consistently over 12 months. Amongst postpartum women, 28.4% initiated contraception within six months. Women viewed themselves as contraception users even if they were not using the methods consistently. Implications: The actual CPR was lower than conventional estimates, demonstrating that conventional estimates of contraceptive use must be corrected to account for periods of non-use. The reliance on short-term methods, and high discontinuation rates contribute to persistently high fertility in Malawi. In a context of relatively good provision of contraceptive services, quality of care must be improved, and strategies to motivate women to adhere to their method of choice must be employed. Promotion of long-acting methods is also key.