Approximately 750,000 women worldwide have undergone ESSURE hysteroscopic sterilization since 2002. In 2015, an increase in adverse effects was noted, with gynaecological and systemic symptoms reported. Scanning electron microscopy (SEM) analysis of fallopian tube and uterine horn tissues and implants, after hysterectomy or salpingectomy, revealed the presence of inorganic particles resulting from implant degradation.Ten patients (age 42-53 years) were included in this study. Of these, eight patients had undergone hysterectomy and two patients had undergone salpingectomy. Mean exposure time was 85.5 months (standard deviation 26.8 months, range 34-105 months). Mineralogical analyses were performed on 13 tissue biopsies and four implants by SEM coupled with energy dispersive x-ray spectrometry.In five of the 10 patients, tin particles were observed in fallopian tube or uterine horn tissues with inflammatory cell reactions. In the other five cases, iron, chromium, nickel or platinum particles were observed. For implants, major deterioration of the weld zone was observed with either destroyed appearance or the presence of an organic coating containing numerous particles.Analysis of the preclinical studies performed by the manufacturer suggests that degradation of the tin weld plays a major role in these adverse events, with increasing leaching and corrosion between 3 and 6 months for an intratubal insert that si designed to remain in an woman's body for her entire life. For patients with gynaecological symptoms (e.g. pain, metrorragies) needing explantation, these findings raise the question of a causal relationship between tin particles from implant degradation and the inflammatory tissue response. For patients with systemic symptoms (e.g. blurred vision, headache, asthenia, myalgia), the hypothesis that these symptoms may be related to the formation of organotin (chemical compounds based on tin with hydrocarbon substituents) in the body has yet to be proven. Tin levels in blood have to be measured before and after explantation. To the authors' knowledge, this is the first study to report significant degradation of the ESSURE implant weld, evidenced by the detection of tin particles in the uterine tissue of patients and comparison of the welding zone between unused and used implants.