Maternal and child mortality is declining in the last two decades but remains relatively high in the low- and middle- income countries (LMICs). About 86% of global maternal deaths occurred in two regions, sub-Saharan Africa (SSA) alone accounted for 66%, and nearly 20% in southern Asia [1–3]. Although global neonatal mortality rate was decreased by 51%, from 36 deaths per 1000 live births in 1990 to 18 deaths per 1000 live births in 2017, still, 2.5 million children died in the first month of life . Sustainable Developmental Goals (SDGs) have target of less than 70 maternal deaths per 100 000 live births and to reduce to about 1.2 million neonatal deaths by 2030. The ambition of these SDGs targets can be achieved by improving maternal and child health services uptake, especially in the high-burden regions of south Asia and SSA .
Use of maternal and child health services (MCH) are essential for the early detection of mothers and infants at high risk of morbidity and mortality. Although there have been improvements in MCH services coverage, overall MCH indicators remained low with disparities between the lowest and highest wealth quintiles [5, 6]. The studies in developing countries stated that high maternal and child mortality was highly related to low level of antenatal care (ANC) visits, facility based delivery, immunization, decision making capacity of women and social capital scores [7–14]. Social capital (SC) can play a role in improving health services uptake and it has been positively related to physical and mental health of members in the social networks [15, 16].
Social capital has multiple definitions and concepts in the field of economics, sociology, political science, public health and other disciplines . Recently, it has become an important issue in field of public health . Social capital is defined as social relations that may provide individuals and groups with access to resources and supports in their community networks. It may include different forms such as exchange of favors, maintenance of group norms, trust towards individuals or groups, and supports offered to members of social groups . A number of social capital theories were grounded so far and growing from individual and family property to features of communities and nations [20–22]. The theory of SC can be explained in structural and cognitive forms. In the structural form, it focuses on the externally observable aspects of social organizations and refers to the intensity of an individual’s participation in community networks measured in objective terms . The cognitive form involves subjective aspects such as norms, values, attitudes and perceptions of an individual’s social relationship and can be measured subjectively. Structural and cognitive forms of SC are not mutually exclusive and characterized in terms of social relations as what people ‘do’ and what people ‘feel’, respectively [15, 24, 25].
Some public health researchers focused on the distinction of social capital into ‘bonding’, ‘bridging’, and ‘linking’ which are highly related to structural SC [24, 26, 27]. Bonding capital comprises relations within homogeneous groups, in terms of establishing strong intra-group ties that connect family members, neighbors, and close friends. Bridging capital refers to weak ties between individuals or groups that possess little social participation. For example, people from different ethnic and occupational backgrounds may attain relatively weak social connections. Linking capital exists among those individuals and groups involved in hierarchical or unequal relations due to differences in power, status, and resources [24, 28].
A study conducted in five LMICs showed that neighborhood social capital has better contribution in LMICs than high-income countries, potentially due to differences in neighborhood environments, health systems, and availability of public resources. In addition, China had the highest level of trust in neighbors; South Africa and Ghana had very high level of community participation and Ghana showed the highest score of perceived safety in the residential neighborhood . Likewise, women in Ethiopia had high levels of group membership, high participation in citizenship activities and high levels of cognitive social capital. Women who involved in social networks including ‘Debo’ and ‘Equb’ could access information. These networks also provide economic and social support to the members and beyond . Social capital influences use of maternal and child health services through social networks between communities or community members and representatives of formal institutions such as health care providers, teachers and government officers . Moreover, involvement of religious leaders, health extension workers, women developmental army leaders, and selected community members could enhance use of maternal and child health services. Women who received health information from people they trust are more likely to access and use health services . Social trust has positive association with better health and safety of a community. Neighborhoods with higher levels of social trust experience lower rates of health and health related problems, and have fewer signs of physical disorder, making residents of these neighborhoods feel safer [34–37].
Despite studies in India [24, 38], Tanzania  and Cameroon countries indicated the role of SC in improving uptake of maternal and child health services, some other studies have identified its negative consequences as exclusion of outsiders, excess claims on group members, restrictions on individual freedoms, and downward leveling norms [41, 42]. To date, there is no study that systematically synthesizes the available literature focusing on social capital's role to improve maternal and child health services use in LMICs. Therefore, this review aimed to synthesize the available literature about the role of social capital on the utilization of maternal and child health services including antenatal care (ANC), institutional delivery and postnatal care (PNC) in LMICs. The findings of the study will inform policy and decision makers to improve maternal and child health services use in LMICs.