COMPARATIVE STUDY OF THE OUTCOME OF INDUCTION OF LABOUR USING 25µg AND 50µg OF VAGINAL MISOPROSTOL

Abstract

Background: There is an increasing use and acceptance of misoprostol for
induction of labour in our environment being a cheap drug as well as being stable
without requiring any special storage facility. However, different dose regimens,
ranging from 25µg to 200µg, have been used for induction of labour with varying
maternal and neonatal outcomes.
Objective: This study is aimed at comparing the safety and effectiveness of
vaginal misoprostol 25μg with those of 50μg in induction of labour.
Method: It was essentially a randomized clinical trial. Pregnant women of low
parity (Para 1, 2 and 3) at term (between 37 and 42 weeks) who had indications for
induction of labour and met the inclusion criteria were randomized into two
groups of vaginal misoprostol 25µg and 50µg dose regimens using the table of
random numbers. One hundred and sixty patients participated in the study with 80
patients in each of the study group. The respective dose, in each group, was
inserted 6 hourly until adequate uterine contractions of 3 in 10 minutes each
lasting 40-50 seconds were achieved or a maximum total daily dose of 200µg of
misoprostol was obtained. Patients with unfavourable cervix (Bishop’s score less
than 7) had cervical ripening with trans-cervical extra-amniotic Foley’s catheter.
Labour was monitored partographically.
Results: The indications for induction of labour were similar in the two groups
(p = 0.51). Postdate pregnancy was the commonest indication in both groups
accounting for 33.8% and 42.5% for 25µg and 50µg groups respectively. Higher
number of patients achieved spontaneous vaginal delivery in 50µg group (93.7%)
than in 25µg group (88.7%), but the difference was not statistically significant,
p=0.26. The total duration of labour was significantly shorter in the 50 µg group
(494.6 ± 90.8 minutes) than 25 µg group (545.4 ± 161.1 minutes), p = 0.02.
Oxytocin augmentation was significantly higher in the 25 µg group (18.75%) than
in the 50 µg group (7.5%), p = 0.04.
The incidence of caesarean section was similar in the two groups, 11.3% and
6.3% for 25µg group and 50µg respectively (p = 0.26), however, the indications
for the caesarean section were significantly different, (p = 0.02). Suspected fetal
distress accounted for 80.0% of the caesarean sections in 50 µg group and 11.1%
of those in 25 µg group.
The intrapartum adverse effects like fetal distress, meconium stained liquor,
and tachysystole were significantly higher in the 50µg group, p = 0.03. Similarly,
the postpartum adverse effects such as cervical and vaginal tears were
significantly higher in 50µg group, p = 0.01.
The Apgar scores of the babies at one minute (p = 0.76) and five minutes (p =
0.37) were, however, similar in the two groups.
Conclusion: The two dose regimens, 25µg and 50µg, were both effective in
induction of labour. The 50µg dose regimen resulted in more vaginal delivery and
significantly shorter duration of labour but with higher rate of labour
complications than the 25 µg dose regimen.

COMPARATIVE STUDY OF THE OUTCOME OF INDUCTION OF LABOUR USING 25µg AND 50µg OF VAGINAL MISOPROSTOL