Shoulder dystocia and range of head-body delivery interval (HBDI): The association between prolonged HBDI and neonatal outcomes: Protocol for a systematic review.

OBJECTIVE: Shoulder dystocia (SD) is an obstetric emergency which if not carefully diagnosed and managed, can contribute to lifelong neonatal morbidities. Despite current guidelines on the definition of SD (impaction of the fetal shoulder behind the maternal symphysis pubis and need for ancillary manoeuvres or head-body delivery interval (HBDI) >60 s) its accurate diagnosis requires clinical expertise as well as overall consideration of feto-maternal condition. Based on the literature available, our study aims to determine (1) the range of HBDI as an indicator of SD and (2) the neonatal complications occurring following prolonged HBDI in normal or SD-complicated births.

STUDY DESIGN: A comprehensive literature search will be conducted in the following databases MEDLINE, CINAHL and Scopus (Elsevier) as well as international obstetric guidelines to find English language published data since 1970 that evaluate HBDI, prolonged HBDI and associated neonatal outcomes. Retrospective/prospective observational studies and randomized controlled trials will be recruited. As heterogeneity in definitions of SD among studies is expected, we will categorize our results according to the following two definitions: 1-Bony obstruction of fetal shoulder behind the maternal symphysis pubis or less commonly, posterior shoulder on sacral promontory and need for ancillary manoeuvres or 2- Head-body delivery interval (HBDI)> 60 s). Two reviewers will independently identify eligible studies, assess risk of bias and extract data based on predefined checklists. Outcomes of interest will be the HBDI in normal and SD-complicated births and associated neonatal consequences.

DISCUSSION: Findings of this systematic review will provide reliable information regarding (1) the interval between birth of the head and birth of the shoulders and (2) neonatal outcomes attributed to either true SD or prolonged HBDI. Our findings will add to the knowledge of whether prolonged HBDI is an appropriate definition for SD and whether/what level of prolongation of HBDI results in adverse neonatal outcomes. This increased understanding will better inform the clinical practice of midwives and obstetricians.