Laminaria as an adjunct in induction of labor

The safety and efficacy of laminaria tents as an adjunct to labor induction near term were examined in a prospective, controlled, and randomized study involving insertion of laminaria into the cervical canal the evening prior to planned induction. Six of 35 subjects in whom laminaria were used entered labor spontaneously and delivered overnight, compared with 1 of 39 controls. Of the remainder, the Bishop score increased an average of 3.7 points, a highly significant change, in the laminaria-treated group compared with no change in the controls. Labor, induced primarily by amniotomy with intravenous oxytocin then given to patients in whom regular contractions did not begin within 8 hours, was shorter with laminaria use than in controls, though the amniotomy-to-delivery interval did not differ significantly. However, comparison of the subgroup with cervices relatively unfavorable for induction, indicated by an initial Bishop score of 5 or less, showed both length of labor and amniotomy-to-delivery interval to be significantly shorter (each by an average of 3 hours) in the laminaria-treated group compared with controls. Complications, including febrile morbidity, did not differ. We conclude that laminaria tents are both effective and safe as an adjunct to labor induction, acting by accelerating the preparatory changes in the cervix which normally occur in late pregnancy.