高达 50%~60% 的妊娠妇女会出现黄褐斑,尤其在晚期妊娠更常见。[13]Lakhdar H, Zouhair K, Khadir K, et al. Evaluation of the effectiveness of a broad-spectrum sunscreen in the prevention of chloasma in pregnant women. J Eur Acad Dermatol Venereol. 2007;21:738-742.http://www.ncbi.nlm.nih.gov/pubmed/17567299?tool=bestpractice.com在孕妇群体中,该现象可通过其与促黑激素 (MSH) 水平升高、炎症后现象和紫外线暴露之间的相关性来解释。[7]Guinot C, Cheffai S, Latreille J, et al. Aggravating factors for melasma: a prospective study in 197 Tunisian patients. J Eur Acad Dermatol Venereol. 2010;24:1060-1069.http://www.ncbi.nlm.nih.gov/pubmed/20202051?tool=bestpractice.com