BACKGROUND The role of estrogens on moles biology remains undefined although estrogenic receptors have been found on melanocytes. It has been postulated that supraphysiological estrogen levels could promote the progression of moles to melanoma. Women undergoing controlled ovarian stimulation (COS) for assisted reproductive technologies (ART) are exposed to high levels of estrogens, produced by the ovary in response to exogenous gonadotropin administration. The aim of this study is to assess whether COS for ART may have an impact on mole structure and/or characteristics. METHODS Women undergoing to ART for various infertility conditions were included in the study. Personal and clinical data were collected. Dermatoscopic features and scores (total dermoscopy score--TDS) were statistically compared before COS and after a 6-month follow-up period. Statistical correlation was performed between estradiol, FSH blood levels and relative variation in moles dimensions. RESULTS A total of 46 patients were included in the study. One hundred and seventy-five melanocytic lesions from 31 patients were evaluated at both time points. Although statistically significant differences were found in mole dimension and TDS between the two time points, these differences had no relevance in the clinical setting not suggesting the need for mole excision. Moreover, the only statistically significant correlation with estradiol blood concentration on hCG administration day was found with one-axis dimensional variation. CONCLUSIONS To our knowledge this is the first work to evaluate the effect of COS on moles. The obtained results do not support a causal relation between the supraphysiological hormone levels stimulation and worsening of clinical and dermoscopical features of moles. Further study is needed to clarify whether estrogens plays a role in melanoma.