The effect of iodine supplementation on oocyte apoptosis and proliferation in women with diminished ovarian reserve: a pilot study

Iodine, an essential trace element, may play a role in reproductive health through its extrathyroidal actions. This study aimed to investigate the effects of iodine supplementation on oocyte apoptosis and proliferation in women with diminished ovarian reserve. A quasi-experimental study was conducted on ten women undergoing two cycles of ovarian stimulation. In the first cycle, they followed the standard protocol, while in the second, they received a daily 150 µg iodine supplement for two months. Urinary iodine levels, cumulus cell apoptosis and necrosis, and PCNA expression were evaluated before and after supplementation. We found that iodine supplementation significantly improved women's iodine status, increasing it from borderline sufficiency to optimal levels. This improvement was accompanied by a significant increase in the number of metaphase II oocytes. Following iodine supplementation, we observed a marked increase in cumulus cell viability and a reduction in both early and late apoptosis. Additionally, the expression of PCNA was upregulated, showing a positive association with the percentage of live cells and a reduction in total apoptosis. These findings suggest that iodine supplementation could be a promising therapeutic strategy for improving oocyte quality and enhancing fertility outcomes, particularly in women with diminished ovarian reserve.