Oral misoprostol for induction of labour at term: randomised controlled trial
BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.38729.513819.63 (Published 02 March 2006) Cite this as: BMJ 2006;332:509
All rapid responses
We were interested to read the article “Misoprostol for induction of
labour at term: randomised controlled trial” by Dodd et al. In recent
years there has been a great interest in the use of misoprostol for
induction of labour. This research article highlights some very important
issues; the best dose regimen to use, tailoring dose to patient
characteristics, safety issues, patient approval of route of
administration and cost effectiveness.
A safe yet effective dose regimen of misoprostol remains to be
determined. Doses of 20 mcg, 25mcg, 50mcg, 100mcg have all been studied.
The 50mcg vaginal dose results in a shorter induction to delivery time1,2,
however, the American College of Obstrecians and Gynaecologists have
recommended a vaginal dose of 25mcg for induction of labour due to a lower
incidence of uterine hyper-stimulation. They also suggested a 3-6 hour
dosing regimen; that oxytocin should not be administered less than four
hours after the last misoprostol dose; induction of labour to be managed
in a hospital; and that misoprostol should not be used for cervical
ripening in patients with a uterine scar.3
This study did not take into account dosing regimens tailored to
patient characteristics, which are predictors of the likelihood of
success. Doses may have to be tailored to parity, initial cervical
dilatation and gestational age.4 Sublingual doses may lead to a reduction
in the total dose delivered.5 Administration of smaller doses remains a
difficult task as currently misoprostol is prepared in 100mcg or 200mcg
tablets and subsequently these tablets need to be divided, giving rise to
possible inaccuracies in administration. Licensing of pre-prepared smaller
doses is imperative for safe usage of this drug.
A good experience of the induction process and labour is of paramount
importance. The patients using misoprostol in this trial gave better
feedback about their experience of induction. Oral misoprostol offers a
less invasive alternative for induction of labour. In addition, oral
misoprostol could potentially reduce the rate of iatrogenic
chorioamnionitis by reducing the number of vaginal examinations.
It is interesting to note that more than 60 systematic reviews6 have
assessed the use of misoprostol in Obstetrics and is now recognised by the
Food and Drug Agency for its use in induction of labour. With such
burgeoning interest in the drug and increasing use, we feel it is
necessary for the Royal College of Obstetricians and Gynaecologists to
produce contemporary guidelines on the use of misoprostol.
References
1.Garry D, Figueroa R, Kalish RB, Catalano CJ, Maulik D. Randomized
controlled trial of vaginal misoprostol versus dinoprostone vaginal
insert for labor induction. J Matern Fetal Neonatal Med 2003; 13(4):254-
259.
2.Lokugamage AU, Forsyth SF, Sullivan KR, El Refaey H, Rodeck CH.
Dinoprostone versus misoprostol: a randomized study of nulliparous women
undergoing induction of labour. Acta Obstetricia et Gynecologica
Scandinavica 2003; 82(2): 133-137.
3.ACOG Committee Opinion. American College of Obstetrician and
Gynecologist. ACOG Committee Opinion. Number 283, May 2003. New U.S. Food
and Drug Administration labelling on Cytotec ( misoprostol) use and
pregnancy. Obstetrics & Gynecology 2003; 101 (5 Pt 1): 1049-1050.
4.Wing DA, Tran S, Paul RH. Factors affecting the likelihood of
successful induction after intravaginal misoprostol application for
cervical ripening and labor induction. American Journal of Obstetrics
& Gynecology 200; 186(6):1237-1240.
5.Shetty A, Mackie L, Danielian P, Rice P, Templeton A. Sublingual
compared with oral misoprostol in term labour induction: a randomised
controlled trial. British Journal of Obstetrics & Gynaecology 2002;
109(6):645-650.
6.Khan RU, El Refaey H. Pharmacokinetics and adverse-effect profile
of rectally administered misoprostol in the third stage of labor.
Obstetrics and Gynecology 2003; 101 (5 Pt 1):968-974
7.Reference to 60 systematic reviews from Cochrane database of
systematic review.
Competing interests:
None declared
Competing interests: No competing interests
Dear Authors
Congratulations on your article.
My response is actually to the photograph on the front cover of the
British Medical Journal, and I have e-mailed the following to the Editor.
Best wishes
Ian Laing
Dear Editor
In the Neonatal Intensive Care Unit we demand that all staff remove
their jewellery at the beginning of each shift. Anyone wearing a watch or
dress ring is deemed not to have washed his/her hands. "Naked from the
elbows down" is the _expression in common usage. Visiting surgeons and all
other disciplines now comply with our regulations.
It was therefore with some disappointment that I viewed the cover
photograph of the BMJ showing a mother squatting in labour. The midwife's
watch on her left wrist is disappearing into the groin of the labouring
woman.
When will we take this subject seriously?
Yours sincerely
Ian Laing
Competing interests:
None declared
Competing interests: No competing interests
Bishop's score (the cervial ripening score) should have been matched or similar in the two interventions arms (oral and vaginal prostaglandins)
The condition of cervix is the most important variable which
determines whether the induction is going to be successful or not.
Bishop's score that determines the consistency of cervix, its position
(anterior or posterior), effacement, dialation and the station of the head
has to be at least five in order to induction to be successful which has
not been recorded in the trial so results cannot be relied upon1. Either
the score should have been excluded or matched and could have as well
become outcome variable along with delivery within 24 hours. Bishop scores
of less than 6 usually require that a cervical ripening method be used
before other methods which mesoprost is, so monitoring of bishop's score
is important both for inclusion in the study and success of the trial. The
transvaginal mesurement of cervical length is considered the better
prognostic measurement than Bishop's score for successful induction(2,3).
References:
1.Nashar S, Dimitrov A, Nikolov A.[Prognostic significance of
Bishop's pelvic score for the continuity and the final outlet of induction
of labor].
Akush Ginekol (Sofiia). 2005;44(5):13-8. Bulgarian.
2. Sieroszewski P, Banach R.[Comparison of the predictive value of
digital examination (Bishop's score) and ultrasound evaluation for labor
induction success]. Ginekol Pol. 2010 Feb;81(2):105-10. Polish.
3.Maitra N, Sharma D, Agarwal S. Transvaginal measurement of cervical
length in the prediction of successful induction of labour.J Obstet
Gynaecol. 2009 Jul;29(5):388-91.
Competing interests: No competing interests