Background: Induction of labour has become commonplace in obstetric practice. The amount of women experiencing induction of labour has grown exponentially. 25% of all pregnancies in the developed world will now end with an induction of labour (Bakker et al, 2013). A pregnancy is considered to have reached full term at 37 weeks gestation. However approximately 10% of all pregnancies will continue past 40 weeks gestation and are then generally considered “prolonged” or “post-dates” (Gulmezoglu et al, 2012; Roos, 2010). Although the reasons why some pregnancies become prolonged are not fully understood the increased potential risk to mother and foetus in these instances are well documented (Olesen et al, 2003). Induction is medically indicated when discontinuing the pregnancy is more beneficial for the mother or baby and is often carried out for prolonged pregnancies, where it has been demonstrated to reduce associated perinatal morbidity and mortality (Gulmezoglu et al. 2006). Delivery after 42 weeks is associated with complications including severe perineal injury (3rd and 4th degree perineal lacerations) related to macrosomia (3.3% vs 2.6% at term), increased risk of caesarean section and postpartum haemorrhage (Caughey, 2016; NCBI 2007). Complications such as chorioamnionitis and endomyometritis also increase progressively post term (Caughy, 2004; Heimstad, 2006). In nulliparous women in particular, complications of pregnancy are seen to increase after 40 weeks gestation (Caughey & Bishop, 2006). Infant morbidities such as meconium and meconium aspiration, neonatal academia, low Apgar scores, macrosomia, and, in turn, birth injury are increased in post term infants (ACOG, 2000). The clinical aim of induction of labour is to achieve a safe vaginal delivery. However, women whose labours are induced report less satisfaction with their overall birth experience (Shetty, 2005). With this in mind it is essential that we examine ways to provide safe, evidence based methods of induction of labour, that are satisfactory to women and clinicians. Induction of labour is a procedure used to stimulate uterine contractions to promote the onset of labour. There are several methods used to obtain this outcome i.e. induction with either prostaglandins and/or oxytocin and/or amniotomy (Boulvain et al, 2005).There are many obstetric clinical factors which need to be considered when choosing the method of induction including parity, as women tend to become more responsive to stimulatory drugs such as oxytocin and prostaglandins if they have previously given birth. Favourability of the cervix, as assessed by the Bishops score, is used as an indication of the probability of induction success and determines whether prostaglandins are necessary (Bishop, 1964). Amniotic membrane sweeping, also referred to as stripping or stretch and sweep of the membranes, is a method of induction which can be used by midwives or obstetricians (Boulvain, 2005). It is a manual technique used to stimulate the normal physiological onset of labour by increasing the release of localised prostaglandins F2α. An amniotic membrane sweep involves detaching the inferior pole of the membranes from the lower uterine segment digitally in a circular movement during a vaginal examination (Boulvain, 2005). Membrane sweeping has not been linked to any increase in maternal or neonatal infection (NICE, 2008). This method has the advantage that it may be utilized independently or in combination with other methods of induction of labour. NICE has recommended the use of this method, which has not been associated with a risk of premature rupture of membranes, from 40 weeks gestation and before beginning formal induction of labour (NICE, 2008; Wong et al, 2002). Membrane sweeping is usually performed without the need for hospital admission thus significantly lowering the cost. The intention when using this method of induction is to promote normality.
Why it is important to do this review?
The aim of evidence based guidelines within healthcare systems is to encourage people and processes that are efficient and patient-focused. As 25% of all pregnancies in the developed world end in a formal induction of labour it is imperative that the accompanying guidelines are current and evidence based (Bakker et al., 2013). Induction of labour is associated with higher rates of instrumental vaginal birth and caesarean section (NICE Guideline, 2008); leading to an increased risk of respiratory distress and trauma to the neonate and prolonged hospital stays (Simonson et al., 2007). In addition, pharmacological methods of induction can lead to an increased risk of uterine hyper stimulation and rupture and foetal compromise (WHO, 2011). Further, pharmacological methods of induction of labour are not suitable for all women, as the use of prostaglandins is contraindicated in cases of women with a previous caesarean section and reduced levels are indicated in grand multiparity (NICE, 2008). The Royal College of Obstetricians and Gynaecologists has also noted that studies to evaluate the use of oxytocin during a VBAC labour have not recorded the indication for oxytocin use (RCOG, 2016). A recent Cochrane review to advice on methods of induction for women with a history of previous caesarean section reported that insufficient information from randomized controlled trials is available to make a recommendation. (Jozwiak, 2012). The WHO recommends that women receiving oxytocin, misoprostol or other prostaglandins should never be unattended as hyper stimulation leading to foetal hypoxia is a known risk (Rameez, Kaluarachchi & Perera, 2011). Such interventions can be seen to add additional strain on already limited health-care resources. This systematic review will provide results of high quality evidence to inform women and clinicians in their practical care options and decisions regarding induction of labour. At present there are no national clinical guidelines on the use of membrane sweeping for induction of labour. An international guideline was last issued by the National Institute for Health and Clinical Excellence (NICE) in July 2008. On issuing this guideline in 2008 NICE recommended further research centered on maximizing the effectiveness and acceptability of membrane sweeping for induction of labour. (NICE, 2008). The World Health Organisation issued its most recent guideline on induction of labour in 2011, again noting that additional research on this topic should be considered a high priority (WHO, 2011). Therefor this review will provide a direct benefit to clinicians and their decision making process, providing a clear framework to inform clinical Practice guidelines in this space both nationally and internationally.
Objective: The objective of this review is to evaluate the effectiveness of amniotic membrane sweep for induction of labour in women at term gestation.
Search Methods: We plan to search the Cochrane Pregnancy and Childbirth Group’s Trials Register and reference lists of retrieved studies.
Criteria for considering studies for this review: Types of studies
We will include randomized trials that compare the effectiveness of amniotic membrane sweeping as a form of induction of labour with no treatment or with a placebo or other method of induction of labour.
Types of participants
Pregnant women requiring third trimester induction of labour who are carrying a live foetus.
Types of interventions
· Amniotic membrane sweeping defined as detaching the inferior pole of the membranes from the lower uterine segment digitally in a circular movement during a vaginal examination (Boulvain, 2005).
· Usual care defined by the World Health Organisation as ‘The aim of the care is to achieve a healthy mother and child with the least possible level of intervention that is compatible with safety.” (WHO, 1996)
· Placebo defined for the purpose of this review as a standard vaginal examination.
· Other methods of induction of labour include amniotomy and/or prostaglandin and/or oxytocin or any combination thereof.
We propose the following five comparisons: 1. Amniotic membrane sweeping versus usual care.
2. Amniotic membrane sweeping versus placebo.
3. Amniotic membrane sweeping versus other methods of induction of labour (all methods).
4. Amniotic membrane sweeping versus other methods of induction of labour (specific methods) 5. Different frequencies of amniotic membrane sweeping as proposed by the National Institute for Health and Clinical Excellence (NICE) recommended research questions (NICE, 2008).
Types of outcomes
We are aware of the ongoing development of a core outcome set (COS) for induction of labour, which is due to be completed in 2016. We propose to consider seriously the use of this COS in this review with supplementation with additional outcomes identified frequently in Cochrane reviews exploring different aspects of induction of labour.
Data collection and analysis: Two review authors will independently assess trials for inclusion and risk of bias, extracted data will then be checked for accuracy. A data extraction form will be created and data on all recorded outcomes in each included paper will be collected and tabulated and reported using a PRISMA checklist
