Clinical chorioamnionitis is a major risk factor for failed vacuum-assisted births - A retrospective cohort study.

OBJECTIVE

To determine the impact of clinical chorioamnionitis on vacuum assisted birth (VAB), alongside other potential risk factors.

STUDY

DESIGN

A retrospective cohort study at a single university-affiliated tertiary medical center between 2011-2023. The study group included singleton pregnancies at ≥ 36 weeks' gestation undergoing a trial of vacuum birth. The study group, comprising cases of failed VAB (defined as failure or abortion of the procedure due to extraction duration over 20 min, more than two cup detachments, or physician's decision to switch to a cesarean birth, and the control group, consisting of successful VAB. Clinical chorioamnionitis was diagnosed with an intrapartum fever of ≥ 38 °C and the presence off either a white blood cell count ≥ 15,000 or documentation of treatment with broad-spectrum antibiotic regimen for clinical chorioamnionitis.

RESULTS

Overall 9,402 births were by VAB, of them, 197 (2.1 %) were classified as failed attempts. Multivariate logistic regression analysis identified clinical chorioamnionitis as the major independent risk factor for failed VAB (OR = 4.1, 95 %CI 2.4-7.2, p < 0.001). Additional risk factors for failed VAB included: occiput posterior position (OR = 1.9, 95 %CI 1.1-3.3, p = 0.017) medical induction of labor (OR = 1.8, 95 %CI 1.2-2.6, p = 0.006), and fetal head station less than + 2 below the ischial spine (OR = 1.7, 95 %CI 1.1-2.6, p = 0.010).

CONCLUSION

Clinical chorioamnionitis significantly increases the risk of failed VAB. The study highlights the necessity of considering clinical chorioamnionitis as a critical factor in planning vacuum assisted births.