Objective: To carry out longitudinal observation of the changes in vaginal microbiota from pre-pregnancy to the postpartum period. Methods: The present study enrolled 80 healthy Chinese women of childbearing age, following them up from pre-pregnancy to the postpartum period. Vaginal secretions were obtained from each of the women to determine bacterial density, bacterial diversity, dominant bacteria, vaginal pH, and Nugent score, by conducting direct microscopy, microscopic examination of Gram-stained samples, and pH test. The vaginal microbiota was classified diagnostically into normal flora, flora inhibition, vulvovaginal candidiasis, bacterial vaginosis, bacterial vaginosis + vulvovaginal candidiasis, and dysbacteria. The associations between the outcomes of both pregnancy and birth and the changes of vaginal microbiota were analyzed by SPSS. Results: Statistically significant differences in vaginal pH, diversity/density, dominant bacteria, and Nugent scoring were see across five time points, ranging from pre-pregnancy to the postpartum period (F = 1307.91, P < 0.01; chi(2) = 417.02, P < 0.01; chi(2) = 402.04, P < 0.01; and chi(2) = 24.62, P = 0.02; respectively). For pathogenic bacteria, fungi were examined at four of the five stages, not including pre-pregnancy. Significant differences were found between the five samples with respect to vaginal microbiota state, including normal, inhibition, and dysbiosis (chi(2) = 416.971, P < 0.01). There were no statistically significant differences in the incidence of vaginal dysbiosis between different time points (all P > 0.05). From pre-pregnancy to late pregnancy, 20 women (25%) maintained normal vaginal microbiota throughout the whole period, while 60 (75%) underwent a dynamic change of vaginal microbiota starting from the early-pregnancy period. By comparing the outcomes of pregnancy between the normal and dysbiosis groups, no significant differences were found in terms of premature rupture of membranes, premature birth, infection, and cesarean section (all P > 0.05). Comparing the outcomes among newborns between the normal and dysbiosis groups at term, no significant differences were found in macrosomia, fetal growth restriction, neonatal jaundice, neonatal infection, and neonatal referral rate (all P > 0.05). Conclusion: In Chinese women, vaginal microbiota during gestation period undergoes dynamic change. Vaginal pH, diversity/density, dominant bacteria, and Nugent score at five time points were significantly different. Vaginal microbiota states, including normal, inhibition, and dysbiosis, were significantly different between the five sampling points. Whether the vaginal microbiota is normal or not is not related to pregnancy and newborn outcomes.