Midwifery and nurse staffing of inpatient maternity services – a systematic scoping review of associations with outcomes and quality of care

Objective To undertake a scoping literature review of studies examining the quantitative association between staffing levels and outcomes for mothers, neonates, and staff. The purpose was to understand the strength of the available evidence, the direction of effects, and to highlight gaps for future research. Data Sources Systematic searches were conducted in Medline (Ovid), Embase (Ovid), CINAHL (EBCSCO), Cochrane Library, TRIP, Web of Science and Scopus. Study Selection and Review methods To be eligible, staffing levels had to be quantified for in-patient settings, such as ante-natal, labour/delivery or post-natal care. Staff groups include registered midwives, nurse midwives or equivalent, and assistant staff working under the supervision of registered professionals. Studies of the quality of care, patient outcomes and staff outcomes were included. All quantitative designs were included, including controlled trials, time series, cross-sectional, cohort studies and case controlled studies. Data were extracted and sources of bias identified by considering the study design, measurement of exposure and outcomes, and risk adjustment. Studies were grouped by outcome noting the direction and significance of effects. Results The search yielded a total of 3280 records and 21 studies were included in this review. There were three randomised controlled trials, eleven cohort studies, one case control study and six cross sectional studies. Seventeen were multicentre studies and nine of them had over 30,000 participants. Reduced incidence of epidural use, augmentation, perineal damage at birth, postpartum haemorrhage, maternal readmission, and neonatal resuscitation were associated with increased midwifery staff. Few studies have suggested a negative impact of increasing staffing rates, although a number of studies have found no significant differences in outcomes. Impact on the mode of birth were unclear. Increasing midwifery support staff was not associated with improved patient outcomes. No studies were found on the impact of low staffing levels for the midwifery workforce. Conclusions and Implications for practice Although there is some evidence that higher midwifery staffing is associated with improved outcomes, current research is insufficient to inform service planning. Studies mainly reported outcomes relating to labour, highlighting a gap in research evidence for the antenatal and postnatal periods. Further studies are needed to assess the costs and consequences of variations in maternity staffing, including the deployment of maternity care assistants and other staff groups. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Peter Griffiths receives support from a Senior Investigator award made by the National Institute for Health Research and the National Institute for Health Research Applied Research Centre (Wessex). This research was part funded by the National Institute for Health Research Health Services & Delivery Research programme (Award ID NIHR128056) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Not applicable All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Not applicable