Lower long-term melasma risk associated with hormonal intrauterine devices compared to combined and progestin-only oral contraceptives

Summary: Abstract Body: Previous studies have suggested potential effects of birth control options on chronic dyspigmentation. This study investigated the risk of melasma in patients treated with hormonal intrauterine devices (hIUDs) vs. progestin-only contraceptives (POCs) and combined oral contraceptives (COCs). We conducted a population-based cohort study including U.S. patients aged 18-52 with menorrhagia treated with hormonal contraceptives between January 2001 and October 2024. Patients were classified into those treated with COCs, POCs, hIUDs, and hormone-unprescribed controls. Propensity score matching controlled for demographics, medications, procedures, and comorbidities. Over 1 year of follow-up, compared to controls, no significant difference in melasma risk was observed among patients on COCs (risk ratio [RR]: 1.50; 95% CI: 0.80-2.83), POCs (RR: 1.00; 95% CI: 0.42-2.40), and hIUDs (RR: 1.00; 95% CI: 0.42-2.41). At 3 years of follow-up, COC-treated patients showed a significantly increased risk of melasma (RR: 2.42; 95% CI: 1.57-3.72), while those on POCs (RR: 1.80; 95% CI: 0.96-3.38) and hIUDs (RR: 1.31; 95% CI: 0.64-2.70) did not. At 5 years of follow-up, a significantly increased risk of melasma was observed for COCs (RR: 2.68; 95% CI: 1.86-3.85) and POCs (RR: 1.95; 95% CI: 1.10-3.43), but not hIUDs (RR: 1.59; 95% CI: 0.87-2.92). Findings did not show significant increased melasma risk conferred by hIUDS, whereas there was increased risk at 3 and 5 years for COCs and at 5 years for POCs, suggesting hIUDs may be the safer option for patients at risk of chronic dyspigmentation. Our findings suggest melasma risk may be proportional to systemic hormone absorption, with highest risk in COCs, followed by POCs and hIUDs. Future studies may explore the potential benefits of switching from oral contraceptives to hIUDs as a strategy for management of patients with pre-existing melasma. Debby Cheng¹, Ahana Gaurav², David Xiang¹, Helen Ji³, David Hirsh¹, Steven Chen³, Arash Mostaghimi², Kevin Sheng-Kai Ma³, Nicholas Theodosakis³ 1. Harvard Medical School, Boston, MA, United States. 2. Brigham and Women's Hospital, Boston, MA, United States. 3. Massachusetts General Hospital, Boston, MA, United States. Pigmentation, Melanoma, and Melanoma Immune Surveillance