Intrafollicular iron and ferritin in women with ovarian endometriomas

Objective To evaluate whether iron contained in ovarian endometriomas can diffuse through the cyst wall and negatively affect ovarian function. Design Prospective case series. Setting Infertility unit in an academic setting. Population Thirty‐nine infertile women with unilateral endometriomas who underwent in vitro fertilization. Methods Iron and ferritin assessments in pools of follicular fluids obtained from affected and contralateral intact gonads. Main outcome measures Iron and ferritin concentrations. Results Follicular fluid iron content did not differ between the two gonads. The median [interquartile range (IQR)] follicular concentrations in the affected and unaffected ovaries were 59 (IQR 44–74) and 59 (IQR 47–73) μg/dL, respectively (p = 0.77). Conversely, ferritin concentration was significantly higher in affected gonads. The median (IQR) concentrations of ferritin in the affected and unaffected ovaries were 57 (IQR 31–146) and 33 (IQR 23–67) μg/mL, respectively (p = 0.026). When considering together the 78 studied ovaries, no significant correlations emerged between follicular iron and ferritin and variables reflecting ovarian responsiveness and oocyte developmental competence. Conclusions Iron may diffuse from ovarian endometriomas into the adjacent ovarian tissue. However, this phenomenon does not appear to markedly affect ovarian function. Some effective biological mechanisms such as ferritin storage may effectively sequester free iron, so limiting its detrimental effects.