Introduction

Adolescence is a critical stage in the life of any human being because physical, cognitive, social and emotional capabilities that are instrumental across the life-course are developed during this stage.1 Crucially, these include capabilities related to sexuality and reproduction—as adolescence is associated with the rapid development of the reproductive organs, the onset of menarche2 and the beginning of sexual activity.3–5 Despite being characterised as the healthiest period in the life of an individual, behaviours that could jeopardise the immediate and future health and well-being are learnt and established at this age.6 However, adolescence also offers enormous opportunities to amend unhealthy behaviours before they become entrenched. The Lancet Commission on health and well-being of adolescents determined that investment in adolescents’ health, education, family and legal support would yield ‘a triple dividend of benefits’ related to the development of critical capabilities during adolescence, future adult-health trajectories and secure the welfare of the next generation.7 The health and well-being of adolescents and young adults is, thus, receiving increasing policy attention worldwide after many decades of neglect. There is a growing recognition that targeting adolescents is critical not only for improving reproductive health and well-being for all but also for addressing other major challenges in global health.7 There will be over 1.8 billion adolescents and young adults globally in 2020, and sub-Saharan Africa (SSA) will account for 22.6% of this population.8 Addressing the sexual and reproductive health (SRH) needs of this population is critical if SSA is to achieve the sustainable development goals, reap a potential demographic dividend9 and its envisaged transformation as articulated in Africa’s overarching Agenda 2063.10

Yet, SSA’s adolescents carry a high burden of SRH-related challenges and associated morbidity, mortality and toll on their future prospects. In many SSA countries, a large proportion of young women become pregnant during adolescence.11 Pregnancy and childbirth in adolescence are linked with adverse maternal and neonatal outcomes, including the increased risks of low birth weight, preterm delivery, severe neonatal conditions, early neonatal deaths, maternal mortality and morbidity.11–15 Also, a large number of adolescent pregnancies in SSA resulted in unsafe abortions performed by unqualified service providers in environments lacking the minimum required medical standards resulting in complications and deaths.15 Consequently, half of all deaths resulting from unsafe abortion in SSA occur among adolescent girls.15

Besides the risk of unintended pregnancy, adolescents are also disproportionately exposed to sexually transmitted diseases. For example, adolescent girls in SSA, in particular, have the highest burden of HIV, with three in five of every new infection among this age cohort.16 Pregnancy and HIV are now the leading causes of deaths among adolescents and young adults in SSA.13 Adolescent girls also bear a huge burden of sexual violence, which further exacerbates their exposure to HIV.17 18 Despite efforts to reduce all forms of violence against girls, available records show that girls, in SSA, in particular, are disproportionately exposed to violence, with female genital mutilation and child marriage still commonly practised.17–22

Adolescents’ heightened risk of SRH-related morbidity and mortality reflects, among others, their limited capacity and poor access to information or service to prevent unplanned pregnancy, negotiate safe sex and consent, prevent sexually transmitted diseases or avoid sexual violence.

To redress this situation, African countries have articulated collective commitments to ensuring adolescents’ access to comprehensive SRH services and supportive environments. The directions are captured in continental frameworks such as the African Union’s Maputo Protocol,23 and the Addis Ababa Declaration on Population and Development.24 However, progress in the domestication and implementation of such commitments through policy, legislation or programming at subregional and national levels has remained limited.25 Two key obstacles to progress are an absence of requisite evidence needed to inform and promote national-level policy debates and processes, but also an insufficient synthesis and marshalling of relevant evidence that already exists.25 A fuller understanding of the landscape of, and key gaps in, existing research and evidence on adolescent SRH in SSA is needed to help address both barriers.

To our knowledge, no prior studies have comprehensively mapped the extant body of literature on this topic in SSA. To address this gap, we aim to conduct a comprehensive scoping review, in order to map the scope and nature of extant research on adolescent sexual and reproductive health and rights (SRHR) in SSA, clarify key concepts, identify key topics and countries for which a knowledge base exists, summarise this knowledge and pinpoint major areas, both substantive and geographical, where further evidence generation is required.

We expect that the findings of the review will offer a useful basis for the planning of further research, but also for the synthesis and marshalling of existing evidence in debates and advocacy to advance evidence-informed, national-level policy and practice that protects the SRH and rights of the large population of young people in SSA.