Meperidine versus valethamate bromide in shortening the duration of active labor

To compare the efficacy and safety of meperidine hydrochloride and valethamate bromide against placebo in shortening the duration of active labor.

We randomly assigned 160 nulliparous women with a singleton pregnancy at term who needed induction of labor to one of 3 treatments: 50 mg of meperidine (n=53), 16 mg of valethamate bromide (n=53), or a normal saline solution as placebo (n=54). All medications were given by slow intravenous infusion. Labor duration was the main outcome measure.

The intervals between infusion and complete cervical dilation and between infusion and delivery were significantly reduced (P<0.001 and P<0.01) in the meperidine group (103.0+/-64.5 minutes and 119.8+/-70.2 minutes), in contrast to the placebo group (173.9+/-74.8 minutes and 192.2+/-82.8 minutes). However, differences were not significant between the 2 treatment groups (139.6+/-63.1 minutes and 160.6+/-71.9 minutes), or between the valethamate bromide and the placebo group.

Meperidine, but not valethamate bromide, significantly shortened the duration of active labor in nulliparous women with a singleton pregnancy at term.