ObjectiveTo explore whether the vaginal environment changes of pregnant women were correlated with pathogenesis of fungal vaginitis. MethodsWe selected 166 women in their early pregnancy in the Obstetrics and Gynaecology Clinic between July 2011 and July 2012 as the study objects (excluding fungal vaginitis patients already confirmed). Two important indicators of changes in pH and the amount of vaginal lactobacilli were chosen to determine changes in the vaginal environment. Using prospective study method, by checking changes in the vaginal environment, the objects were divided into two groups: 96 were in the changing environment group, and 70 were in the normal environment group. Sixty seven of them had a pH value lower or equal to 4.0, and 99 higher than 4.0. Fifty-eight of them had a reduced amount of lactobacillus, and 108 had a normal amount of lactobacillus. The rate of fungal vaginitis in each group was counted. ResultsThe morbidity rate in patients whose pH value was lower than or equal to 4.0 was 17.9% (12/67), while it was 6.1% (6/99) in patients with a pH value higher than 4.0, and the difference was significant (χ2=5.804, P=0.016). The morbidity rate in patients with a reduced amount of lactobacillus was 25.9% (15/58), and it was 2.8% (3/108) in patients with normal lactobacillus, and the difference was also significant (χ2=20.800, P=0.000). The morbidity rate for patients with changing vaginal environment was 16.7% (16/96), and for those with normal environment was 2.9% (2/70), and the difference was significant (χ2=7.985, P=0.005). In those with normal lactobacillus, the reduction of pH value was not correlated with the occurrence of fungal vaginitis (χ2=0.000, P=1.000). ConclusionThe vaginal environment changes during pregnancy (pH value decrease and Lactobacillus decrease) are associated with the incidence of fungal vaginitis, and it can be prevented and treated based on this phenomenon.