• Toiba Reyaz
• Sadiya Javed
• Saima Ashraf

The vaginal microbiome plays a crucial and dynamic role in maintaining reproductive health and reflects the hormonal fluctuations that define a woman’s menstrual cycle. This study aimed to investigate the cyclic variations in vaginal microbial composition and their potential as non-invasive biomarkers for predicting ovulation. A prospective observational study was conducted among thirty healthy women aged 20–35 years with regular menstrual cycles, from whom vaginal swabs were collected during the follicular (Day 5–7), ovulatory (Day 13–15, confirmed by LH surge), and luteal (Day 20–22) phases. DNA extraction was performed using the Qiagen DNA Mini Kit, and 16S rRNA sequencing of the V3–V4 region was carried out on the Illumina MiSeq platform, followed by taxonomic and diversity analyses. The results demonstrated significant phase-specific microbial transitions, with Lactobacillus crispatus dominating the follicular phase (60%), Lactobacillus iners prevailing during ovulation (70%), and Gardnerella vaginalis and Atopobium vaginae emerging in the luteal phase. A notable reduction in microbial diversity (Shannon Index 1.3 ± 0.3) and a strong positive correlation between L. iners abundance and estrogen levels (r = 0.71, p < 0.01) were observed during the ovulatory phase, indicating hormonally driven ecological restructuring. Machine learning models achieved 85.6% accuracy in predicting ovulation based on microbial profiles, confirming that vaginal microbial dynamics mirror endocrine rhythms. The study concludes that the vaginal microbiome acts as a biological chronometer capable of predicting ovulation with high precision, offering a promising, non-invasive, and biologically integrated tool for personalized fertility monitoring and reproductive health management.

Keywords: Hormonal Fluctuations, Biomarkers, Correlation, Ovulation, Chronometer

"ROLE OF VAGINAL MICROBIOME IN PREDICTING OVULATION", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 11, page no.a832-a850, November-2025, Available :http://www.jetir.org/papers/JETIR2511096.pdf

"ROLE OF VAGINAL MICROBIOME IN PREDICTING OVULATION", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 11, page no. ppa832-a850, November-2025, Available at : http://www.jetir.org/papers/JETIR2511096.pdf