Risk Factors of Intra-Amniotic Infection Related to Induction with Single-Balloon Catheter: A Case-Control Study.

AIMS: To investigate the risk factors of intra-amniotic infection (IAI) related to induction with single-balloon catheter (SBC).

METHODS

A retrospective, case-control study including 58 cases of IAI patients who underwent induction with SBC was conducted in Women's Hospital, School of Medicine, Zhejiang University. For each case, 8 women who delivered during the same month and had no infection after SBC induction were selected for control.

RESULTS

Compared with the control group, the IAI group had a higher rate of nulliparity (87.93 vs. 70.69%; p = 0.006), BMI > 30 kg/m2 (29.31 vs. 15.95%; p = 0.011), and amniotic fluid index (AFI) < 8 cm (32.8 vs. 15.1%; p = 0.001). The diameter of cervical dilatation when membranes ruptured in IAI group was smaller than that in the control group (2.0 [1.5] vs. 3.0 [8.0] cm; p < 0.001). Time from start of induction to vaginal delivery was longer than that in the control group (47.0 [19.75] vs. 27.0 [16.0] h; p < 0.001). After logistic regression, the 5 factors associated with IAI for those who underwent SBC induction were nulliparity, BMI > 30 kg/m2, AFI < 8 cm, diameter of cervical dilatation < 3 cm when membranes ruptured and time from start of induction to vaginal delivery of more than 48 h.

CONCLUSIONS

Focus on these risk factors could result in earlier prophylaxis so that the incidence of IAI could be reduced.