Results Our systematic search resulted in a total of 8,509 references. Following evaluation of their title and abstract, 371 papers remained for full text review. After reviewing these papers, 171 papers did not meet our inclusion criteria, leaving 210 papers for analysis (Fig 1). The papers’ study objective and study design are shown in S4 Table. The majority of the included papers used quantitative methods. We found an increase in the number of papers published over the past four decades, with a peak in the years 1989 (n = 9) and 1995 (n = 9) and more than half of the papers published in the last 10 years (2009–2018). The included papers originated from 24 high income countries. Most papers originated from North America, Europe and Australia, with the highest numbers of papers from the USA (n = 55), the Netherlands (n = 48), England (n = 27) and Australia (n = 27). We identified three main categories, which can be seen as the three dimensions of risk selection; (1) risk selection as anorganisational measure to optimally align women’s and children’s needs and resources, (2) risk selection as a practice to detect and assess risk and to make decisions about the delivery of care, and (3) risk selection as a tool to ensure safe care. We found that these dimensions of risk selection had three themes in common: across these dimensions risk selection is (1) viewed as bothrequiring and providing regulation, (2) has a provider centred focus and (3) aims toavoid underuse of care (Fig 2). In all papers one or more main categories were present. In S4 Table we show the dominant category per paper. We illustrate our findings by referring to the most relevant papers. Risk selection as an organisational measure: Aligning risk and resources Papers focussing on organisation of MNC refer to risk selection as a means for care systems to manage a common challenge: meeting the needs of childbearing women and their children with limited resources. These needs are referred to in terms of ‘risk’. Risk has a negative connotation, associated with pathology or abnormality, and is described using terms such as, ‘illness’ [42], ‘complication’ [43], ‘disease’, [44], ‘problem’ [21], ‘disorder’ [45]. In the included papers, risk sometimes indicates anunwanted event [46,47], the cause of an unwanted event [48,49], or the probability of an unwanted event [50,51], which may or may not occur, adversely effecting outcomes of care. Risk selection is used to allocate resources and align women’s and children’s needs with MNC services. Allocation of resources is considered effective when necessary care is provided by health care professionals with the appropriate level of expertise, in the most appropriate place, where the appropriate facilities and resources are located, with the type and timing of care planned appropriately [52–57]. For example, Posthumus and colleagues [58] studied the interaction between access to care, care demand and care supply. According to Reddy and colleagues [59] effective use of resources implies that specialist services should be reserved for women with complications or those at most risk of developing complications. Nuovo [60] pointed out that risk selection is especially important when consulting care providers do not have immediate access to specialist care, enabling them to plan the necessary care. In the papers addressing the organisation of MNC, at least one of the following attributes of healthcare services is discussed as precondition to optimally align needs and resources: availability, access, and timeliness of care [61]. Risk selection is described as an instrument to balance access to, and availability of resources with the perceived likelihood of needs, while ensuring timeliness of care. Timeliness refers to the geographical distribution of resources, and the distance and time to reach them. As such, transportation is emphasized as essential to achieve timely care [62–66]. Availability of resources includes availability of expertise, facility, technology, diagnostics and therapy [67–74]. For example, Hein & Burmeister [75] explained ONE Risk selection in maternal and newborn care | June 8, 2020 4 / 22 72 3 CHAPTER 3