Intrafollicular iron and ferritin in women with ovarian endometriomas

OBJECTIVE: To evaluate whether iron contained in ovarian endometriomas may diffuse through the cyst wall and negatively affect ovarian function. DESIGN: Prospective case series. SETTING: Infertility unit of an academic setting. POPULATION: 39 infertile women with unilateral endometriomas who underwent IVF. 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 concentration in the affected and unaffected ovaries was 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) concentration of ferritin in the affected and unaffected ovaries was 57 (IQR 31-146) and 33 (IQR 23-67) μg/mL, respectively (p=0.026). When considering altogether 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, thus limiting its detrimental effects.