Introduction
Induction of labour has been increasing over the last decade accounting for a significant proportion of deliveries1. The induction of labour is most often indicated for a variety of reasons such as post-term pregnancy (defined as ≥42 weeks gestation), prelabour rupture of the amniotic membranes, or when the safety of the baby or mother may be compromised by a prolonged pregnancy2. Methods for induction of labour include the use of prostaglandins, oxytocin, mifepristone, nitric oxides, membrane sweeping, catheters, amniotomies, and other non-traditional methods. The method of induction depends on hospital protocol, national guidelines, and clinical factors3. Each method has advantages and drawbacks with implications for the well-being of the mother during and after parturition. Since decisions regarding induction can be time-sensitive, it is critical to define the efficacy and safety of the methods employed.
Evidence-based medicine is defined as using the best available evidence to inform clinical decision-making4. Systematic reviews and meta-analyses sit at the top of the hierarchy of evidence and integrate the best available evidence to aid in clinical-decision making5. However, when multiple systematic reviews are available and synthesis of their conclusions is not undertaken with methodological rigour, the reliability of conclusions and thus the validity of decisions arising from them may suffer. In the absence of a thorough assessment of study quality and combining the knowledge gleaned from multiple systematic reviews it becomes increasingly difficult for clinicians, policy-makers, and other knowledge users to draw reliable conclusions. To guide a minimal standard for preparing systematic reviews and meta-analyses, the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement was developed and published in 2009. PRISMA is a 27-item checklist of reporting items that are deemed essential for transparent conduct and reporting in systematic reviews6. In addition to PRISMA, the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) tool was developed to evaluate the methodological quality of a systematic review and meta-analysis7. AMSTAR is an 11-item validated and reliable tool that has been used in numerous studies to evaluate the quality of systematic reviews. It is important to adhere to both checklists to ensure transparent reporting. This systematic review fulfills the PRISMA criteria, as well as the AMSTAR criteria where applicable.