Search methods for identification of studies
The review was undertaken by searching the Ovid SP version of MEDLINE
and EMBASE and the Cochrane Pregnancy and Childbirth Group’s Trials
Register from 2011 to June 2019, followed by a manual search of
references of relevant articles (reviews) and clinical guidelines (ACOG,
NICE, UpToDate) for eligible studies. The length of the review period
was restricted to 2011 to June 2019 because NICE clinical guideline for
planned CS was updated in 2011 and scoping work showed that this
guideline would enable identification of all relevant studies to capture
the most important outcomes up until that date. The search strategy used
in electronic databases was based upon a combination of terms relating
to caesarean section; vaginal birth; and planned (Appendix S1).
Abstracts and conference proceedings were excluded because of the high
probability of incomplete data. Citations were collated using EndNote X9
and Microsoft Excel and duplicates were removed.