The impact of serum estradiol levels on vaginal pH and Candida infections during infertility treatment.

PURPOSE: This study aimed to evaluate the potential impact of serum E2 levels on vaginal pH regulation and Candida colonization in women undergoing infertility treatment, emphasizing mucosal barrier dynamics and epithelial immune modulation.

METHODS

In this prospective observational study, 60 women aged 20-49 undergoing long-protocol ovulation induction were enrolled. Serum E2 levels, vaginal pH, and fungal cultures were assessed on cycle day 2 (baseline) and again at the time of estradiol peak, which was typically within 24 h before human chorionic gonadotropin (hCG) administration and after ultrasound-confirmed follicular maturation. Pre- and post-treatment paired samples were statistically compared, with significance set at p < 0.05.

RESULTS

Post-treatment analysis revealed a significant increase in serum E2 and vaginal pH levels (p < 0.05). However, no significant correlation was observed between E2 and vaginal pH, Candida colonization, or vulvovaginal symptoms. Likewise, vaginal pH was not a significant predictor of fungal growth. Notably, a significant association between baseline symptoms and culture positivity was observed pre-treatment, which was not present post-treatment.

CONCLUSION

These findings indicate that the hormonal increase in E2 during infertility treatment, although associated with elevated vaginal pH, does not increase the risk of Candida infections. The preservation of epithelial barrier function despite hormonal shifts may explain this finding. These results support the microbiological safety of controlled ovarian stimulation protocols with regard to Candida susceptibility.