Ann. Pak. Inst. Med. Sci. 2010; 6(2): 96-100

Objective: To compare the efficacy of oral and sublingual misoprostol.
Study design: Quasi-experimental
Setting: OB/GYN Department, Holy Family Hospital, Rawalpindi.
Duration: The study was conducted from 1-10-2006 to 31-3-2007.
Materials and Methods: Primigravida to Para 3 at term who needed induction of labour were divided in two groups. Group A received Misoprostol orally 100 microgram and Group B sublingual, repeated 4 hourly to a maximum of 4 doses or till labour was induced.
Main Outcome Measures: Incidence of failed induction, induction delivery interval, mode of delivery, maternal and fetal outcome. Variables like age, parity, gestational age and number of doses of misoprostol were also noted.
Results: 3 (6%) women had failed induction in group A whereas all women in group B went into labour. Mean induction to delivery interval was 10.47 + 8.03 hours in Group A and 6.40 ± 5.10 hours in Group B. In Group B 72% had normal vaginal delivery while 20% had instrumental delivery and 8% had C. section (p=0.057).In Group A 66% had normal vaginal delivery and 34% had C-section. 44% in Group A and 60% in Group B were had an induction delivery interval less than 12 hours (p=0.000).In Group A 16% babies had meconium aspiration. In Group A 2 women had hyper stimulation while in Group B 1 woman had hyper stimulation and 1 mother had tachystole.
Conclusion: 100 ug misoprostol 4 hourly is safe and effective for induction of labour with sublingual route giving a better outcome.
Key words:Misoprostol,Induction of labour,Induction delivery interval


Introduction

Labour induction is the initiation of uterine contractions prior to their spontaneous onset for the purpose of accomplishing delivery of the feto/placental unit.¹ Induction of labour is done whenever there is definite benefit to the health of mother and/or baby, greater than if pregnancy continues. ² It can be done by surgical or medical means. Among medical agents many inducing agents are available including oxytocin, prostaglandins and its various analogues.³ With more than 15% pregnant women requiring cervical ripening at the time of labour induction, there is immense interest and demand for an effective and safe method of induction.⁴ Two forms of prostaglandins are commonly used for cervical ripening prior to induction of labour at term: misoprostol (a synthetic PGE1 analogue) and dinoprostone(PGE2). A large multicentric open label trial showed that low dose misoprostol had efficacy and safety similar to dinoprostone with 22 pounds reduction in cost per induction.⁵
Similarly, a large number of randomized controlled studies have assessed the efficacy and safety of misoprostol, in different doses, with different dose intervals and different routes including oral, vaginal, rectal & sublingual.⁶ Apart from low cost, it has many other advantages in comparison with other therapies including easy storage at room temperature for many years⁷, being an E1 analogue it has no effect on bronchi or blood vessels and only side effects of note are diarrhoea and shivering both of which are dose dependent and self- limiting. After federal drug agency (FDA) approval in USA and recommendation the drug is now being used widely.
Oral and sublingual routes seem easy options because of easier administration and no restriction on mobility of the woman.⁸
Many different doses have been tried world wide. A dose of 100ug has been found to be safe, effective, well tolerated with short induction to delivery interval and lower rates of caesarean section.⁹
However, concerns still remain regarding uterine hyper stimulation affecting the blood supply to fetus leading to meconium stained amniotic fluid and uterine rupture, though data of perinatal out come have been reassuring.¹⁰
Purpose of this study is to compare oral and sublingual misoprostol for induction of labour at term in women from primigravida to para 3.