Vaginal organic acids and hormonal changes in the menstrual cycle

Area of Science:

• Gynecology
• Reproductive Endocrinology
• Microbiology

Background:

• Vaginal microbiota play a crucial role in reproductive health.
• Hormonal fluctuations during the menstrual cycle influence the vaginal environment.
• Oral contraceptives (OCs) are widely used and may impact vaginal physiology.

Purpose of the Study:

• To investigate the impact of oral contraceptive (OC) use on vaginal short-chain aliphatic acids and lactic acid.
• To explore the relationship between vaginal acids and reproductive hormones (estrogen, progesterone, LH) throughout the menstrual cycle.

Main Methods:

• Studied 27 women not using OCs and 22 women using OCs over one menstrual cycle.
• Collected 24-hour vaginal secretions via tampon method on alternate days.
• Analyzed vaginal secretions for acetic, other short-chain aliphatic acids, and lactic acid.
• Measured daily blood levels of estrogens, progesterone (P), and luteinizing hormone (LH).

Main Results:

• No significant differences in the amount or variability of vaginal aliphatic acids were observed between OC users and nonusers.
• Vaginal aliphatic acid levels did not correlate with estrogen or progesterone levels in either group.
• A significant positive correlation was found between vaginal lactic acid and blood estrogen levels in women not using OCs.

Conclusions:

• Oral contraceptive use does not appear to significantly alter the profile of vaginal short-chain aliphatic acids.
• Vaginal lactic acid production in non-OC users is positively associated with circulating estrogen levels.
• These findings suggest hormonal influences on vaginal acidity are distinct from the effects of OC use on aliphatic acid profiles.