Sub-Optimal Menstrual Materials and Vaginal Microbiome Disruption in Women Relying on Sex for Livelihood

Supriya Dinesh Mehta^1,2*Garazi Zulaika³Edyth Osire⁴Walter Agingu⁴Paul Souvik¹Cynthia Akinyi⁴Stefan Green⁵Anna M van Eijk³Runa Bhaumik¹Fredrick Odhiambo Otieno⁴Penelope A Phillips-Howard³

• ¹University of Illinois Chicago, Chicago, United States
• ²Rush University, Chicago, United States
• ³Liverpool School of Tropical Medicine, Liverpool, United Kingdom
• ⁴Nyanza Reproductive Health Society, Kisumu, Kenya
• ⁵Rush University Medical Center, Chicago, United States

Background: Sub-optimal menstrual materials (MM), such as using cloths, cotton balls, or tissues, can adversely affect the vaginal microbiome (VMB). Women who rely on sex for economic livelihood often use sub-optimal materials to conceal menstruation and avoid loss of income. We hypothesized that among women who rely on sex for economic livelihood, those using sub-optimal MM would be more likely to have non-optimal VMB than those with adequate MM. Methods: This cross-sectional analysis used baseline data from women participating in a trial assessing the impact of reusable menstrual discs on the VMB, Bacterial vaginosis (BV), and sexually transmitted infections (STIs). Data on sociodemographics, menstrual materials, and sexual practices were collected via interviewer-administered survey. Clinician-collected vaginal samples were tested for BV, STI, and VMB. VMB was assessed via 16S rRNA gene amplicon sequencing. A suite of statistical approaches identified factors associated with sub-optimal MM (use of cotton balls, tissue, or cloth) and VMB composition. Results: 407 women were enrolled February through October 2023, with median age 27 years, 24.7% were HIV-positive, 42.2% had BV, and 21.9% had STI (composite of chlamydia, gonorrhea, trichomoniasis). Vaginal community state type (CST) was primarily diverse (CST-IV; 63.5%), or Lactobacillus iners dominated (CST-III; 28.1%), while CST-I (L. crispatus dominated) was uncommon (7.9%). Sub-optimal MM was reported by 42.0% of participants and in multivariable modeling, was more common among women with indicators of economic strain. In multivariable analyses, alpha diversity was higher with sub-optimal MM and indicators of economic strain. Suboptimal MM was associated with CST-IV in crude analyses but was attenuated and non-significant when adjusted for age, educational attainment, amount paid at last sexual encounter, number of sex partners, and HSV-2. Non-targeted machine learning algorithms identified non-optimal VMB taxa with greater relative abundance among women with sub-optimal MM. Discussion: Sub-optimal menstrual materials were used commonly and associated with non-optimal VMB composition. Reusable menstrual discs that may be worn during sex may address the economic factors driving sub-optimal MM that are associated with non-optimal VMB.