Significance of cervical ripening in pre-induction treatment for premature rupture of membranes at term

AimThis study aimed to determine whether mechanical cervical dilatation with a laminaria tent in women with premature rupture of membranes (PROM) at term may influence the maternal/neonatal outcomes. MethodsWe reviewed the medical records and histopathologic results of the placenta in 782 women with PROM at term. Of the 486 women seen prior to 2010 (group 1), 85 had Bishop scores of 5 or less and underwent insertion of laminaria tents (group A). In the 296 women admitted after 2010 (group 2), 27 had Bishop scores of 5 or less and underwent labor management without insertion of laminaria tents (group B). The patient characteristics, delivery course and neonatal outcomes were compared between the groups. ResultsThere were no significant differences in the maternal age, percentage of nulliparas, body mass index, gestational age at delivery or Bishop score between the groups. The Bishop score improved from 2.5 to 6.1 after laminaria tent insertion in group A. However, there were no significant intergroup differences in the frequency of use of labor-inducing agents or the time interval from PROM to delivery. The incidence of clinical/pathological chorioamnionitis was not higher in group A than in group B. No significant differences were found in the Apgar scores, umbilical artery pH or frequency of asphyxia neonatorum between the groups. Mechanical cervical dilatation by laminaria tent insertion neither increased the incidence of infection nor contributed to improvement of the perinatal prognosis. ConclusionMechanical cervical dilatation does not provide any benefit for women with PROM at term.