BACKGROUND: Polymorphic eruption of pregnancy (PEP) is a pruritic disease that usually occurs in primiparous women, most commonly in the last trimester of pregnancy. The origin and pathomechanisms still remain unknown. OBJECTIVES: We attempted to determine the parameters that may be associated with or complicate the course of PEP. METHODS: Data of 200 pregnant women (40 PEP and 160 control) were studied retrospectively and compared statistically using univariable and multivariable analysis. RESULTS: In multivariate analysis, pregnancy with male fetuses (P = .02) and delivery by cesarean section (P = .012) were overrepresented in the PEP group. A tendency toward more multiple gestation pregnancy in PEP was found (P = .07). The risk of PEP was not related to excessive maternal or fetal weight gain. LIMITATIONS: This was a retrospective study. CONCLUSION: This large case-control study confirms the already suspected association of PEP with male fetuses and cesarean deliveries in multivariate analysis. The higher rate of multiple gestation pregnancy was also established.