Duration of Labor. Clinical Trial
Official title:
The Impact of Papaverine on First Stage of Labor
In the investigators institution, there is a wide use of Papaverine in delivery room, but
this use is optional, and is left to the discretion of the physician.
The aim of the investigators study is to prospectively evaluate the influence of Papaverine
administration in the latent phase of labor, on the duration of labor.
Cervical dilatation rate and the duration of delivery are key issues in the management of
labor. Protracted labor is known to be associated with a range of potential maternal and
neonatal complications, including higher rate of post partum hemorrhage (PPH), cesarean
sections, instrumental deliveries, maternal or neonatal infections and neonatal pulmonary
asphyxia [1,2,3]. Thus, there is a rationale for reducing the duration of labor in order to
reduce adverse pregnancy outcome.
Active management of labor as was demonstrated by O'driscoll et al. was found to be
effective in shortening the duration of delivery [1, 4]. There is a variety of mechanical
and medical methods for labor induction and augmentation. Mechanical methods include
artificial rupture of membranes (amniotomy), with or without the use of Pitocin [5, 6],
manual sweeping of the amniotic membranes which promotes the release of prostaglandins [7],
and extra-amniotic balloon [8]. Medical methods such as prostaglandins and Pitocin are well
studied and were found to reduce the duration of labor.
Papaverine and its derivatives have been studied in the nineties of the last century and
were found to be effective in reducing the duration of the first stage of labor [9, 10, 11].
Drotaverine hydrochloride is an analog of Papaverine and a selective inhibitor of
phosphodiesterase 4. It was found to be effective in accelerating cervical dilatation
through smooth muscle relaxation.
In a prospective randomized controlled trial that included 146 women in spontaneous vaginal
delivery, Madhu et al. have shown that women who were treated with Drotaverine through the
latent phase of labor, had significantly shorter duration of time between the administration
of the medication and the delivery of the fetus, compared to women that were treated with
placebo (182 minutes compared to 245 minutes with placebo). Moreover, the cervical
dilatation rate in the Drotaverine group was significantly higher than this in the placebo
group (3 centimeters per hour (cm\Hr) compared to 1.4 cm\Hr) [9]. These findings are in
agreement with Shmara et al. that have also demonstrated a significant reduction in the
duration of labor and a significant acceleration in cervical dilatation rate with
Drotaverine administration compared to placebo. In this study 100% of women who were treated
with Drotaverine in the latent phase of labor have delivered in 6 hours from the
administration, compared to 46% in the placebo group [10].
Only few previous studies have addressed the influence of Papaverine administration on the
duration of labor [9-12], and these studies are limited by small sample size, and different
administration protocols. Moreover, in part of these studies, the use of Papaverine was not
separate from the use of other methods for labor augmentation such as amniotomy or Pitocin
administration, what could bias their results.
In the investigators institution, there is a wide use of Papaverine in delivery room, but
this use is optional, and is left to the discretion of the physician.
The aim of the investigators study is to prospectively evaluate the influence of Papaverine
administration in the latent phase of labor, on the duration of labor.
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Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment