36: Amnioinfusion does not increase the risk of intraamniotic infection

Amnioinfusion is the instillation of fluid into the uterine cavity through an intrauterine pressure catheter (IUPC) and is often used in labor to relieve variable decelerations. There is theoretical concern that amnioinfusion may increase the risk of intraamniotic infection due to washing out of the bacteriostatic properties of amniotic fluid. We sought to examine if the use of IUPC and amnioinfusion results in increased incidence of intraamniotic infection compared to IUPC placement alone. A retrospective cohort study was performed on women who had an IUPC placed in labor from June 2017 to June 2018 at a tertiary care center. Clinical intraamniotic infection was defined as a maternal intrapartum fever and one of more the following: maternal leukocytosis, purulent cervical drainage, or fetal tachycardia. Women who had a diagnosis of intraamniotic infection prior to placement of IUPC were excluded. Multivariable logistic regression was performed to compare women who had an IUPC alone to those with an IUPC and amnioinfusion after adjusting for age, race, body mass index (BMI kg/m2), gestational age and length of rupture of membranes. The adjusted odds ratio (aOR) with 95% confidence interval (CI) were obtained. Of 513 women who received an IUPC in labor, 130 (25.3%) received an amnioinfusion. Demographic data between the women who did and did not receive amnioinfusion were similar, except women who received an IUPC with amnioinfusion had a lower BMI (33.4 vs. 35.3 kg/m2, P=0.02). The rates of cesarean delivery, median length of time of rupture of membranes (ROM), and median length of time of IUPC placement were similar in both groups (Table 1). Compared to women with an IUPC alone, women with IUPC and amnioinfusion did not have increased odds of intraamniotic infection (5.5% vs. 5.4%; aOR 1.16 [95% CI 0.47-2.86]) or postpartum endometritis (3.4% vs 3.9%; aOR 1.13 [95% CI 0.39-3.29]). In contrast to theoretical concern, our data suggests that amnioinfusion does not increase the rate of intraamniotic infection when compared to IUPC placement alone.