Background: Pityriasis rosea (PR) is a self-limiting exanthematous disease associated with human herpesvirus (HHV)-6 and/or HHV-7 reactivation. In pregnant women, PR may be associated with pregnancy complications. Objective: To determine relevant risk factors in the development of negative pregnancy outcome in PR. Methods: Between 2005 and 2017 at the Department of Dermatology, University of Genoa, we recruited 76 women who developed PR during pregnancy. In 60 patients without known risk factors for intrauterine fetal death (30 with pregnancy complications and 30 without) we analyzed the pregnancy week of PR onset, presence of enanthem and of constitutional symptoms, PR body surface area involvement, age, and in 50 patients (20 with pregnancy complications and 30 without), the viral load of HHV-6 and HHV-7 (copies/mL). Results: In logistic regression analysis, early onset of PR (p = 0.0017) and enanthem (p = 0.0392) proved to be significantly associated with pregnancy complications. HHV-6 viral load (copies/mL) (p < 0.0001), constitutional symptoms (p < 0.001), and PR body surface area involvement (p < 0.004) were also significantly associated with pregnancy complications. Conclusion: The onset of PR before week 15 and enanthem may be considered major risk factors that should alarm the dermatologist. Constitutional symptoms and involvement of > 50% of the body area may be considered minor risk factors.