The effect of compound Lactobacillus on the reproductive tract of childbearing-aged women

INTERVENTION: Participants will be randomly allocated to the intervention group or the control group. The researcher will generate a random sequence with a random number table. The envelope method is used to carry out concealed allocation: 116 opaque envelopes are taken, the envelopes are marked with the number of the injection group, and the grouping information according to the randomisation form is indicated in the envelopes, and the envelopes are sealed. After the participants are enrolled in the group in sequence, the researchers open the envelopes one by one, determine the grouping of the patients according to the distribution plan in the envelope, and extract the corresponding products. Participants in the intervention group will receive compound Lactobacillus one sachet/day, while participants in the control group will receive a placebo one sachet/day. Participants take the sachet orally with meals daily for one menstrual cycle without interruption during menstruation. Participants are required to take stool and vaginal discharge samples before the intervention, on day 7, day 14, and 2‐3 days after the end of the next menstrual period, and to complete the research questionnaire before the intervention, on day 7, day 14, day 21, and 3‐5 days after the end of the next menstrual period. CONDITION: Women with a vaginal pH greater than 4.5 ; Urological and Genital Diseases PRIMARY OUTCOME: Vaginal pH values are measured using a self‐testing vaginal pH kit at baseline, 7, 14, 21, and 2‐3 days after the next menstruation SECONDARY OUTCOME: ; 1. The relative abundance and increase of the three strains in virginal discharge will be measured using vaginal discharge collection kits at baseline, 7, and 2‐3 days after the next menstruation; 2. The abundance and increase of Lactobacillus in virginal discharge will be measured using vaginal discharge collection kits at baseline, 7, and 2‐3 days after the next menstruation; 3. The detected rate and abundance of the virginal particular pathogen will be measured using vaginal discharge collection kits at baseline, 7, and 2‐3 days after the next menstruation; 4. The increase and relative abundance of the three strains in feces will be measured using fecal collection kits at baseline, 7, and 2‐3 days after the next menstruation; 5. The relative abundance and increase of Lactobacillus in feces will be measured using fecal collection kits at baseline, 7, and 2‐3 days after the next menstruation; 6. The comparison of alpha‐diversity of the fecal microbiota will be measured using fecal collection kits at baseline, 7, and 2‐3 days after the next menstruation; 7. The increase of the relative abundance of short‐chain fatty acid producing bacteria in gut microbiota will be measured using fecal collection kits at baseline, 7, and 2‐3 days after the next menstruation; INCLUSION CRITERIA: 1. Non‐menopausal women aged 18‐55 years 2. Self‐test vaginal pH value over 4.5 at 2 or 3 days after menstruation 3. Willing to stop consuming probiotic supplements (yoghurt excluded) within 1 week of enrollment and to stop consuming fiber supplements during the intervention 4. Sign the informed consent