To investigate the microecological status of vaginal microflora in pregnant women with preterm rupture of membranes (PPROM) and to compare the effects of different anti-infection treatment timing on pregnancy outcome.

Total of 120 patients with PPROM admitted to Kaizhou District People’s Hospital of Chongqing from January 2015 to January 2019 were selected as PPROM group. While 120 healthy pregnant women who delivered in our hospital during the same period were selected as control group. The pregnant women in PPROM group were divided into early group and late group by random draw method, with 60 cases in each group. Anti-infective therapy was given to the cases in early group 6 h after membrane rupture, and to the cases in late group 24 h after membrane rupture. The vaginal microflora, pregnancy outcome, neonatal birth weight and neonatal hospitalization duration were compared among the three groups, respectively.

The incidence of vaginal bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), BV + VVC and microflora disorders of pregnant women in early group and late group were significantly higher than those in control group, with significant differences (all P < 0.05). The proportion of Gram positive cocci of pregnant women in early group and late group were significantly higher than that of control group (χ² = 9.591, P = 0.002; χ² = 9.591, P = 0.002), but the proportion of Gram positive bacilli in pregnant women in early group and late group were significantly lower than that of control group (χ² = 11.379, P = 0.001; χ² = 12.851, P < 0.001). There was no statistically significant difference between the proportions of Gram-positive cocci and Gram-positive bacilli of pregnant women in early group and late group (χ² = 0.000, P = 1.000; χ² = 0.039, P = 0.843). The rates of intrauterine infection, neonatal septicemia and neonatal mortality of cases in early group and control group were significantly lower than those of late group (all P < 0.05). There was no significant difference in the incidence of neonatal asphyxia among the three groups (χ² = 3.077, P = 0.215). There was no significant difference between the above pregnancy outcome of cases in early group and control group (all P > 0.05). The hospitalization time of neonates in the three group were significantly different (F = 309.216, P < 0.001). The hospitalization time of newborns in early group and late group were significantly higher than that of control group (t = 11.541, P < 0.001; t = 23.771, P < 0.001). There was no significant difference in birth weight among the three groups (F = 0.269, P = 0.764).

Vaginal microecology of pregnant women with PPROM had obvious abnormality, and the increase of microecology imbalance was the main manifestation. Anti-infection treatment at 6 h after membrane rupture could significantly improve the pregnancy outcome of PPROM pregnant women.