Results
A total of 71 women were included in the study group, of whom 40 experienced complete thickness uterine rupture and 31 had uterine scar dehiscence. They were compared to 97 cases of successful VBAC matched by maternal age, BMI, gestational age, and neonatal birth weights of the first and second deliveries.
The basic characteristics of the study and the control groups are shown in Table 1. Maternal age, gravidity and parity were higher in the study group, as expected by the study design. The study group included women with dehiscence or asymptomatic rupture in a repeat CD, whereas the control group included only women after their first VBAC, which means they only had one prior CD. Although the study group was statistically older than the control group (30.2 ± 4.8 years vs. 27.8 ± 4.6 years, p=0), this difference is not clinically significant. There were no significant differences between the groups regarding neonatal birth weight at first delivery and a statistical, but not clinically meaningful difference in birth weight at the second delivery. These potential confounders were included in the logistic regression (Tables 2,3). Infection in the previous delivery remained statistically significant, with odds ratio of 3.41
Sixteen of 71 (22.5%) women with uterine rupture or dehiscence during the current birth, had an infection in proximity to their previous CD, compared to 8 of 97 (8.2%) in the control group (p=0.01).
We also compared the group with complete uterine rupture to the control group. Among 40 women with uterine rupture, 10 (25%) had an infection at their first CD, as compared to 8 of 97 (8.2%) of the controls (p=0.008). This result remained statistically significant in the logistic regression (Table 3). There was no difference regarding the infection rate between the uterine rupture group and the dehiscence group (25% vs. 16%, p= 0.27).
We divided the type of infection into three groups: intrapartum fever, postpartum fever and SSI. SSI and in particular endometritis, had the strongest correlation to uterine rupture at subsequent delivery. None of the control group patients had endometritis, but 7 of 71 (9.8%) in the study group and 5 of 40 (12.8%) in the complete rupture group did. No significant difference was found between groups in terms of intrapartum fever (Table 4).