Rectal versus Intramuscular Hyoscine: its Effects on Shortening the First Stage of Labor in Term Primigravid Women

Spasmolytic drugs such as hyoscine have been proven to enhance cervical dilatation and accelerate the stages of labor. The aim of this study was to compare rectal and intramuscular hyoscine in shortening the first stage of labor in term primigravid women.
In this randomized clinical trial, 80 pregnant women were selected by convenience sampling. One group received two 10 mg rectal suppositories, whereas 2ml intramuscular (IM) hyoscine was administered for the other group, both at the onset of the active phase of labor. The two groups were compared in terms of labor stages, cervix dilatation rate, maternal blood and heart rate, Apgar score at birth and fetal heart rate. The collected data were analyzed using SPSS software (version 21.0).
The mean age of women in the rectal and intramuscular hyoscine groups was 24.5±3.2 and 24.65±4.45 years, respectively. The duration of first and second stages of labor was not significantly different between the two groups (P>0.05); whereas the third stage of labor in the rectal hyoscine group was significantly shorter than IM hyoscine group (P=0.001). The mean 1st and 5th min Apgar scores and the fetal heart rate after drug administration were significantly different between the two groups (P<0.05).
Hyoscine rectal suppository, which is faster absorbed and avoids gastric irritation, was significantly more effective in shortening the duration of labor in comparison to IM hyoscine, although the difference was only in the 3rd stage of labor. Therefore, it is recommended in all pregnancies for accelerating the process of labor.