Vaginal birth core information set: study protocol for a Delphi study to achieve a consensus on a 'core information set' for vaginal birth.

Introduction: Studies have shown that women are often underinformed about potential benefits and risks of vaginal birth. This is in contrast to other modes of birth, such as caesarean birth, for which the risks/benefits are often conveyed prior to undergoing the procedure. A core information set (CIS) is an agreed set of information points that should be discussed with all patients prior to undergoing a procedure or intervention.