International Multicentre Term Prelabor Rupture of Membranes Study: evaluation of predictors of clinical chorioamnionitis and postpartum fever in patients with prelabor rupture of membranes at term.

OBJECTIVES: Our purpose was to determine significant predictors for the development of clinical chorioamnionitis and postpartum fever in patients with prelabor rupture of membranes at term.

STUDY DESIGN: Logistic regression analysis with odds ratios and 95% confidence intervals was used to determine the significant predictors of clinical chorioamnionitis and postpartum fever in women with prelabor rupture of membranes at term enrolled in this study. The study recently compared in a randomized controlled trial four strategies of management: induction with oxytocin, induction with prostaglandin, expectant management, and, if failed, induction with oxytocin or prostaglandin.

RESULTS: The following variables were significantly associated with clinical chorioamnionitis: (1) number of digital vaginal examinations: > 8, 7 to 8, 5 to 6, 3 to 4 (vs 0 to 2) (odds ratio 5.07, 3.80, 2.62, 2.06); (2) duration of active labor: > or = 12, 9 to < 12, 6 to < 9 hours (vs < 3 hours) (odds ratio 4.12, 2.94, 1.97); (3) meconium-stained amniotic fluid (odds ratio 2.28); (4) parity of 0 (odds ratio 1.80); (5) time from membrane rupture to active labor: > or = 48, 24 to < 48 hours (vs < 12 hours) (odds ratio 1.76, 1.77); and (6) group B streptococcal colonization (odds ratio 1.71). Variables significantly associated with postpartum fever were (1) clinical chorioamnionitis (odds ratio 5.37), (2) duration of active labor: > or = 12, 9 to < 12, 6 to < 9, 2 to < 6 hours (vs < 3 hours) (odds ratio 4.86, 3.53, 3.46, 3.04), (3) cesarean section, operative vaginal delivery (odds ratio 3.97, 1.86), (4) group B streptococcal colonization (odds ratio 1.88), and (5) maternal antibiotics before delivery (odds ratio 1.94).

CONCLUSIONS: Increasing numbers of digital vaginal examinations, longer duration of active labor, and meconium staining of the amniotic fluid were the most important risk factors for the development of clinical chorioamnionitis in women with prelabor rupture of membranes at term. The most important risk factors for the development of postpartum fever were clinical chorioamnionitis, increasing duration of active labor, and cesarean section delivery.