Although malaria in pregnancy predisposes women to increased perinatal mortality and morbidity, complex issues underlie its persistence. To develop a better understanding of the factors affecting women's access to Intermittent Preventive Treatment in Benin, we used the theoretical lens of “sensemaking” to clarify policymakers’, health professionals’, and women's perspectives concerning preventive policies and barriers to access. Several assumptions were found to underlie Benin's malaria preventive policy that contribute to the unintended effect of deterring pregnant women in poverty from accessing preventive treatment. Health system dysfunctions including drug shortages and deficiencies in health care professionalism exacerbate the unintended effect.