Journal of Womens Health, Issues and Care ISSN: 2325-9795

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Research Article, J Womens Health Issues Care Vol: 3 Issue: 4

Prostaglandins for Elective Induction of Labour in Term Nulliparous Asian Women with Unfavourable Cervix

Puliyath Geetha*
Department of Obstetrics and Gynaecology, SUT Academy of Medical Sciences, Trivandrum, 695028 Kerala, India
Corresponding author : Puliyath Geetha
Department of Obstetrics and Gynaecology, SUT Academy of Medical Sciences, Trivandrum, 695028 Kerala, India
E-mail:
[email protected]
Received: April 14, 2014 Accepted: July 25, 2014 Published: July 29, 2014
Citation: Puliyath Geetha (2014) Prostaglandins for Elective Induction of Labour in Term Nulliparous Asian Women with Unfavourable Cervix. J Womens Health, Issues Care 3:4. doi:10.4172/2325-9795.1000153

Abstract

Prostaglandins for Elective Induction of Labour in Term Nulliparous Asian Women with Unfavourable Cervix

The aim of elective induction of labour is to reduce maternal and foetal morbidity and mortality. Studies have showed that if pregnancy is continued beyond 41 weeks, there is an increased maternal and foetal complication. However labour induction in women with unfavourable cervix especially if nulliparous, often may lead to prolonged labour and failed induction and high risk of caesarean delivery.

Keywords: Induction of labour; Prostaglandins; Nulliparous women

Keywords

Induction of labour; Prostaglandins; Nulliparous women

Introduction

The aim of elective induction of labour is to reduce maternal and foetal morbidity and mortality. Studies have showed that if pregnancy is continued beyond 41 weeks, there is an increased maternal and foetal complication [1,2]. However labour induction in women with unfavourable cervix especially if nulliparous, often may lead to prolonged labour and failed induction and high risk of caesarean delivery [1-3]. Therefore it is important to find out an effective and safe method of induction of labour in women with unfavourable cervix. There are various prostaglandin preparations available for cervical ripening and labour induction which has been shown to reduce the risk of failed induction [4,5]. Misoprostol a natural analogue of prostaglandin E1 is a cheap, easy to store and an effective drug for ripening the cervix and induction of labour [6-8]. Prostaglandin E2 (dinoprostone) is also widely used for ripening and induction of labour [9]. Even though many published data confirm the safety and efficacy of intravaginal misoprostol, there is concern of tachysystole and hyperstimulation which may be dose dependent [10]. Compared with oxytocin, misoprostol results in a shorter inductionto- delivery interval and decreased rate of caesarean delivery for failed induction [11,12]. Vaginal administration of prostaglandin E1 is found to be as effective as prostaglandin E2 vaginal gel for cervical ripening and induction of labour [13]. The present study is a comparative one between prostaglandin E1 tablet 25 μg and prostaglandin E2 vaginal gel 2 mg for induction of labour in nulliparous women of Asian origin.

Materials and Methods

This is a retrospective study conducted in two tertiary care hospitals from 2007 to 201 2 (5 years). It consisted of application of prostaglandin E1 (misoprostol) tablet 25 μg in one group of nulliparous women, conducted in SUT Academy of medical sciences, Kerala and another group was induced with prostaglandin E2 vaginal gel 2 mg, conducted in Armed Forces hospital Muscat. The two groups were compared with those with spontaneous onset of labour. The study was approved by institutional ethic committee. We retrieved the data from medical record section where the records of labour charts were stored in the electronic system. The inclusion criteria were age more than 18 years , nulliparous Asian women ,done accurate dating of pregnancy in the first trimester scan, singleton term pregnancy, cephalic presentation, Bishop’s score 5 or less , intact membranes ,normal liquor volume and active nonstress test. Cases with prelabour rupture of membranes, gestational or chronic hypertension, gestational diabetes, previous caesarean section, multiple pregnancy, oligohydramnios, intrauterine growth retardation, nonvertex presentations were excluded from the study as these complications may affect maternal and fetal outcome. From 2007 onwards misoprostol tablet (25 μg) was the standard induction agent used in SUT Academy of medical sciences Kerala and prostaglandin E2 vaginal gel (2 mg) was the induction agent used in Armed forces hospital Muscat during that period. Both misoprostol tablet and prostaglandin E2 vaginal gel (2 mg) was kept in the posterior fornix of vagina and repeated after 6 hrs. The subsequent doses was withheld in the presence of at least 3 regular uterine contractions in 10 minutes. As per hospital protocols, Oxytocin was given for acceleration of labour in both groups, when the cervix was more than 4 cm dilated and desired uterine contractions were not present. It was given at 1 mU/minute, increased by 1 mU/minute every 30 minutes till adequate contractions persisted. In all women the progress of labour was monitored by keeping a partogramme. If there was no establishment of labour after 3 doses, the cases were considered as failed induction and caesarean section was done. Hypertonic uterine action is defined as one contraction lasting for more than 2 minutes and uterine tachysystole as more than five contractions per 10 minutes. Non reassuring foetal heart rate pattern is one with persistent or recurring episodes of severe variable decelerations, late decelerations, prolonged fetal bradycardia or a combination of decreased beat-to-beat variability and a decelerative pattern. Hyperstimulation syndrome is defined as the presence of non-reassuring foetal heart rate pattern combined with either tachysystole or hypertonic uterine action [2,14]. Efficacy of induction agents were judged by change of Bishop Score, vaginal delivery rate in 24 hours, doses of drugs needed to induce delivery, Oxytocin augmentation, rate of caesarean section, uterine hyper stimulation rates and maternal adverse effects. Neonatal outcome included APGAR score at 5 minutes; incidence of meconeum stained amniotic fluid, and need for Neonatal Intensive Care Unit (NICU) admission.
Statistical method
Comparison of proportion of different characteristics across the three groups was carried out by using chi-square test and statistical significance was assessed at 5% level.

Results

There were 210 women in PGE1 group, 201 in PGE2 group and 216 in control group. All were Asian women and there was no statistically significant difference in age, height and weight of women, birth weight and sex of babies in three groups. The percentage of women who had normal vaginal delivery was 51.9%, 59.7% and 70.4%, in PGE1, PGE2 and control group respectively. Vacuum delivery was 5.7% ,8.9%and 5.1% and Caesarean section was 42.4%, 31.3% and 24.5%, in PGE1,PGE2 and control group respectively (Table 1).
Table 1: Mode of delivery and indications for Caesarean section.
Caesarean sections were done for failed induction was 35.95% and 41.29% in PGE1 and PGE2 group respectively. For foetal distress it was 24.71%, 38.09% and 28.30% in PGE1, PGE2 and control group respectively. Caesarean sections for failed progress of labour were 39.32%, 20.63% and 71.69% in PGE1, PGE2 and control group respectively. Women going into spontaneous labour had maximum vaginal deliveries than the induced women (Chi-square (4 d.f.)=17.6; P<0.01). However there was no statistically significant difference in mode of delivery or indication for caesarean section among PGE1 and PGE2 groups. Induction delivery interval was more than 24 hrs in 33.7% of women in PGE1 group and 57.14% in PGE2 group. The requirement of a third dose of drug was 23.8% in PGE1 group and 40.3% in PGE2 group, which was statistically significant. (Chi-square (2 d.f.)=12.0; P <0.01) (Table 2).
Table 2: Obstetrical Outcome.
Oxytocin acceleration was required in 60.5%, 61.2% and 85.6% in PGE1, PGE2 and control group respectively .The requirement of oxytocin acceleration was similar in both PGE1 and PGE2 groups. There was no case of uterine tachysystole or hypertonic uterine action or rupture uterus in any of the three groups. There was a case of traumatic and four atonic postpartum hemorrhages besides three cases of vaginal hematoma and two abruption in PGE1 group. There were three cases of atonic postpartum hemorrhages in PGE2 group. There were eight atonic postpartum hemorrhages one abruption and one vaginal hematoma in spontaneous onset group. No statistically significant difference in post partum hemorrhage or blood transfusion was observed in the study. There was no case of postpartum fever or maternal death in any of the group. The APGAR score less than 7 at 5 minutes was 2.9%, 7.5% and 0.5% in PGE1, PGE2 and control group respectively (Chi-square (2 d.f.)=17.6; P<0.001). Higher in PGE2 group. However the Neonatal intensive care unit (NICU) admissions and meconeum stained amniotic fluid were similar in all three groups. No cases of perinatal death were noted in any of the groups.

Discussion

Comparative studies by using 25 μg PGE1 for induction of labour with 2 mg PGE2 vaginal gel and those with spontaneous onset of labour are rare in literature. Several studies have shown vaginal misoprostol to be more effective than dinoprostone for cervical ripening and induction of labour [15-23]. Cochrane review shows that PGE1 at dosages more than 25 μg was associated with short induction delivery interval and lower use of Oxytocin with PGE1 group compared with PGE2 group. However there was increased meconeum staining, higher risks of tachysystole and hyperstimulation with PGE1 compared with PGE2 [14]. In a systematic review by Craine J et al, out of fourteen studies three provided information regarding nulliparous women and they concluded that there was no difference in caesarean section between PGE1 and PGE2 groups. Studies with misoprostol at a dose of 25 μg did not show any differences in the outcomes [24]. The present study with 25 μg PGE1 tablet showed a reduced induction delivery interval and less requirement of third dose of drug with PGE1 compared to PGE2 group and did not cause uterine hyper stimulation or increased rate of foetal heart rate changes. This is similar to study by van Gemund N, et al. [25]. The need for Oxytocin was similar in PGE1 and PGE2 group in our study. Some other clinical trials also indicates that the optimal dose of misoprostol was 25 μg at an interval of 4 to 6 hrs which was associated with less uterine hyper stimulation, less foetal distress and less incidence of neonatal care unit admission. However lower dose of misoprostol was associated with increased need of Oxytocin for augmentation [26]. Some studies have noted PGE1 was associated with increased risk of postpartum hemorrhage and rupture uterus. However the overall incidence of caesarean section rates appears to be reduced, despite a relative increase in caesarean sections for fetal heart rate abnormalities. Using small dosages of PGE1 appears to reduce adverse outcomes [27]. In our study, there was no statistically significant difference in mode of delivery among PGE1 and PGE2 groups. There was no case of uterine hyper stimulation or rupture uterus in this study. However the main limitation of the study is its small size and retrospective nature.

Conclusion

The study showed a favourable outcome with prostaglandin inductions of labour. Women going into spontaneous labour had maximum vaginal deliveries than the induced women. However there was no statistically significant difference in mode of delivery or indication for caesarean section among PGE1 and PGE2 groups. Induction delivery interval more than 24 hrs and the requirement of a third dose of drug were slightly more in PGE2 group than in PGE1 group. The APGAR score less than 7 at 5 minutes was slightly higher in PGE2 group. However the Neonatal intensive care unit (NICU) admissions and meconeum stained amniotic fluid were similar and both prostaglandins do not cause uterine hyper stimulation. A multi centre comparative study including large number of women is necessary to conclude the results to give a definite opinion regarding the safety and efficacy of lower dose of PGE1 tablet for induction of labour.

Acknowledgment

First author involved in design of the study, analysis, interpretation of data and drafting the article. Second author involved in collection, analysis and interpretation of data. No funding from any source was provided for conducting this study.

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