Preterm birth is the leading cause of perinatal morbidity and mortality in otherwise healthy infants, and the rate of pregnancies complicated by a premature delivery continues to rise. Subsequently, attempts have been made to reduce this rate by using progesterone supplementation during pregnancy. 17alpha-Hydroxyprogesterone caproate (17P), a metabolite of progesterone, also has been used as supplementation during pregnancy to prevent preterm births. We report a case of iatrogenic autoimmune progesterone dermatitis (APD) in a pregnant woman who received 17P therapy. Due to the increased use of 17P, our case could represent an increasingly prevalent entity that dermatologists and obstetricians should recognize. In this article, we discuss our findings and provide a basic review of APD.