About the Author
Varsha L. Deshmukh is UG as well as PG examiner since last 15 years. She has about thirty (30) publications in national and international journals. She is reviewer for two national journals. She is interested in high-risk pregnancy and infertility.
Objective To determine the effects of oral misoprostol solution for induction of labour.
Study Design This is a prospective observational study.
Setting This study was conducted in Government Medical College, Aurangabad.
Method Patients undergoing induction of labour after 36 weeks of pregnancy were allocated by randomization to induction of labour with oral misoprostol solution administered 2 h apart. Delivery within 24 h after induction with oral misoprostol solution was the primary outcome on which the sample size was based. The data were analysed by Statistical Software for Social Sciences software.
Result Two hundred patients were randomly selected for induction with oral misoprostol solution. There were no significant differences in substantive outcomes. Vaginal delivery within 24 h was achieved in 80.5 % of patients. The caesarean section rate was 19.5 %. Uterine hyperactivity occurred in 4 % of patients. The response to induction of labour in women with unfavourable cervices (modified Bishop’s score < 2) was somewhat slower with misoprostol, induction to delivery interval was more, oxytocin requirement was more, and vaginal delivery rate was less.
Conclusion This new approach to oral misoprostol solution administration was successful in achieving vaginal delivery rate in 24 h in 80.5 % of patients; rate of LSCS was less 19.5 %.
Keywords : Induction of labour, Oral misoprostol solution, Induction-delivery interval
Induction of labour at term is a common obstetric intervention [1]. Induction of labour is the artificial initiation of labour before its spontaneous onset for the purpose of delivery of the fetoplacental unit using mechanical or pharmacological methods [2]. The goal of labour induction is to stimulate uterine contractions before spontaneous onset of labour, resulting in vaginal delivery [3].
Cheaper alternatives, stable at room temperature, have the potential to produce substantial cost savings in developing countries and allow safe induction of labour in those countries which cannot provide pharmacological induction of labour [1]. Misoprostol, a synthetic prostaglandin E1 analogue, presents low cost, storage at room temperature, and widespread availability [4].
Misoprostol is a unique prostaglandin E1 analogue. Tablets, marketed for anti-inflammatory drug-induced gastric ulceration, are stable and inexpensive [5–7]. The use of misoprostol in pregnancy has been reviewed since long [8]. Introduction of misoprostol was done by Sanchez- Ramos et al. [9] in 1993. Several randomized trials of labour with misoprostol have been undertaken [10–16].
Certain disadvantages are associated with oxytocin use like need to administer it by intravenous route, lack of stability at room temperature, shorter shelf life, and being relatively expensive. Misoprostol has advantages of being easy to use, convenient administration by various routes like the vaginal, sublingual and oral, being stable at room temperature, having a longer shelf life, and being relatively inexpensive [17].
Taking the advantage of short half life of misoprostol, we planned to use small doses at frequent intervals of misoprostol to find out the induction-delivery interval, rate of vaginal delivery, and the neonatal outcome.
Overall, misoprostol may be the best prostaglandin for labour induction, as titrated low-dose oral solution seems to be the safest in terms of caesarean section risk, while vaginal misoprostol tablets (>=50 lg) are the most effective in achieving vaginal delivery within 24 h of induction [18].
A prospective observational study of oral misoprostol solution for induction of labour was conducted at Department of Obstetrics and Gynaecology, Government Medical College, Aurangabad, from October 2013 to October 2015. The permission was obtained from college ethical committee.
Patients recruited in the study were primigravida at term with obstetric or medical indication for labour induction. These patients were either booked attending antenatal clinic regularly (had at least 3 antenatal visits) or emergency admissions in labour room.
A total of 200 patients were randomly selected for the study.
The method of induction of labour was explained to patients, and only those who gave consent were finally selected for the study.
1. Primigravida.
2. Pregnancy between 36 and 42 weeks of gestation.
3. A live singleton foetus in cephalic presentation.
4. No history of uterine surgery.
5. Clinically adequate pelvis.
6. Modified Bishop’s score <= 5.
7. Reactive NST.
1. Known hypersensitivity or contraindications to oral
misoprostol (uterine surgery).
2. Patient’s refusal to give consent.
3. Any antenatal medical complications.
4. A situation requiring LSCS.
5. Non-reacting NST.
Each patient was questioned in detail and examined thoroughly. Last menstrual period was ascertained and correlated clinically. Patients who met the inclusion criteria were selected, and a well informed written consent was obtained for every participant.
Residential belonging rural or urban was noted. Obstetric history—gravida, para, period of menstrual life noted.
General examination, systemic examination, per abdomen examination, and per vaginal examination were done.
Modified Bishop’s score was calculated.
Blood and urine investigations were done. Ultrasonography findings noted to know the gestational age, amount of liquor, severity of IUGR, and placental localization.
Non-stress test performed in each woman and those with reactive NST was selected.
Women were given 20 ml (20 lg) of misoprostol solution orally every 2 hourly until adequate uterine contractions occurred (3 contractions per 10 min lasting 30–40 s).
To overcome the problem of breaking the 200 lg tablet of misoprostol into small fragments, we dissolved the tablet in 200 ml of water (1 lg per ml) shaking the solution well before each administration. Thus, exact 20 lg of misoprostol solution could be administered. Storage of solution was done at room temperature for max 24 h in a glass bottle.
• Measuring jug
• Spoon
• Clean drinking water (200 ml)
• 1 Misoprostol tablet (200 micrograms)
• Clean bottle
The timing and strength of uterine contractions were assessed by regular abdominal palpation.
Foetal heart rate and uterine activity were continuously monitored by electronic foetal heart rate monitor. Temperature, pulse, blood pressure, and occurrence of any side effects of the drug monitored.
Patients reassessed every 2 hourly for adequate uterine contractions (3 contractions for every 10 min lasting for 30–40 s). Repeat 20 lg oral misoprostol solution was given.
Modified Bishop’s score was assessed at 6 h after the first dose, and whether it remained unchanged or increased to 5 or more than 5 was noted. In case of Bishop’s score, less than 5 repeat misoprostol solution dose was given.
In case of adequate uterine contractions, per vaginal examination was done. The cervix was defined as favourable if cervical dilatation was >= 4 cm with 30 % effacement. In patients with favourable cervix, amniotomy was done, colour of liquor was observed, and WHO partograph was plotted. Further doses of misoprostol were not administered to these patients and progress of labour was observed as they entered the active phase of labour. If subsequent contractions become inadequate (< 3 contraction in 10 min lasting for < 20 s.) or no progress of labour for 2 h on partograph, those patients started with oxytocin administration. Timing of oxytocin administration was noted.
Oxytocin administration was started as 2.5 U oxytocin in 500 ml of ringer lactate at the rate of 15 drops per minute. Dose of oxytocin escalated by increasing the drop rate by 15 drops/minute at half hourly interval till maximum 60 drops per minute. If still patient had inadequate contractions, next 5 units of oxytocin were dissolved in 500 ml normal saline at the rate of 30 drops per minute. FHR and uterine contractions were monitored continuously on CTG machine.
Progress of labour was monitored. Any drug reaction or side effect was noted.
If a woman was not in active phase of labour afterreceiving 10 doses of misoprostol solution or failed todeliver within 24 h after initial administration of miso-prostol, patients who required LSCS for failure to progresswere categorized as failed induction.
Women who delivered vaginally within 24 h from initial administration of misoprostol were considered as successful induction.
Primary Outcome
1. Induction-delivery interval.
2. Rate of LSCS
Data entry, data checking, and analysis were done.
Statistical Analysis
To test outcome, qualitative data were analysed, and Pearson’s Chi-square test was used as a test of significance.
Observations and Results
The number of patients randomized was 200.
The number of patients randomized was 200. Data were notkept on patients excluded from participation. The charac-teristics of patients at trial entry are listed in Table1.Postdated pregnancy (37.5 %), premature rupture of membranes (20 %), and hypertensive disorders of preg-nancy (29 %) were the most common indications for induction of labour. Most patients had an unfavourablecervix. The mean pre-induction modified Bishop’s scorewas 3.23±0.67. Ten percentage of patients had pre-in-duction modified Bishop’s score of 0–2, 86.5 % of patientshad pre-induction modified Bishop’s score of 3–4, and3.5 % of patients had pre-induction modified Bishop’sscore of 5. The mean modified Bishop’s score at 6 h afterinduction was 5.18±0.87. 24.5 % of patients had modi-fied Bishop’s score of 5–8 at 6 h after induction
Of the patients (Table2), vaginal delivery within 24 hwas achieved in 80.5 %. There were 19.5 % of caesareansection, mean induction to delivery interval was14.16±3.45 h, and 31 % of patients required oxytocin augmentation.
In particular, there were no serious side effects withmisoprostol solution (Table3). Ten percentage of patientshad nausea, and 5.5 % of patients had vomiting. Theincidence of tachysystole was only 3 %.
The neonatal outcome is listed in Table4. 6.5 % ofpatients had meconium-stained amniotic fluid, 3 % ofbabies were admitted of which 33.33 % were admitted formeconium aspiration syndrome, 3 % of babies hadAPGAR score ofB7 at 1 min, and 1.5 % of babies hadAPGAR score ofB7 at 5 min. Take-home baby rate was100 %.
Table5shows that less the pre-induction modifiedBishop’s score, more the induction-delivery interval is, lessthe vaginal delivery rate is, and more the oxytocin
augmentation required after induction with oral misopros-tol solution.
Low-dose oral misoprostol solution for induction of labouris effective in achieving vaginal delivery within 24 h, lessLSCS rate, lower uterine hyper stimulation syndrome,lower foetal distress, effective as far as safety of motherand baby is concerned.
Our results are consistent with the study done by Dod-det al. [19] in 2006, Cheng et al. [20] in 2008, and Aalami-Harandi et al. [21] in 2012.
Lowering the dose of misoprostol does not seem toresult in lower rates of vaginal delivery; indeed, the con-verse seems to have been the case with significant lowerLSCS rates as compared to other methods of induction oflabour.
This can be explained on the basis of frequency andstrength of contractions that determine the outcome oflabour. High-frequency contractions may reduce the effi-ciency of myometrial acidemia. This provides a mechanism by which lower-frequency doses of misoprostolcan be more efficient than higher doses.
Apart from clinical advantages of oral misoprostol, thesolution also offers the advantage in terms of dose accuracyand patient satisfaction. This leads to the curtailing ofproblems such as failure to progress, or hyper stimulation syndrome.
As misoprostol solution retains its efficacy for at least24 h and solution remains at room temperature, it can bemade only once in 24 h. This adds to the convenience also.It is not surprising that oral route is more acceptable to thepatients because of ease of administration and avoidance ofvaginal examination. Only 31 % of patients required oxy-tocin augmentation, whereas 69 % of patients did notrequire oxytocin augmentation after induction with oralmisoprostol solution.
Compliance with Ethical Standards
Conflict of interest None.
Ethical Approval Approval of ethical committee has been takenfrom Government Medical College, Aurangabad.
