BMJ Global Health · Published 2026-07-01 · DOI 10.1136/bmjgh-2025-020106
Tharindu Wickramaarachchi, Marie Habito, Davide De Beni, Federica Maurizio, Sylvia Wong, Elissa Kennedy, Nick Scott
Introduction Adolescent pregnancy remains a concern in Southeast Asia, with pregnancy both a driver and an outcome of child marriage or union. For Cambodia, Indonesia, the Philippines, Lao People’s Democratic Republic (PDR) and Malaysia, this study aimed to calculate the benefit-cost ratio of investing in evidence-based interventions to prevent adolescent pregnancy and child marriage, considering their complex interdependencies.Methods The population of girls aged 15–19 years was modelled at a national level, stratified by marriage, poverty and school enrolment status (known risk factors for pregnancy). Time-varying inputs for sociodemographics, contraception use, pregnancy and marriage were taken from population surveys (eg, Demographic and Health Survey [DHS]) and census data. A targeted review identified interventions with sufficient cost and effectiveness evidence for inclusion in modelling. A baseline scenario (constant intervention coverage over 2024–2030) was compared with investment scenarios, with interventions scaled up to reach an aspirational 95% coverage by 2030.Results Evidence-based interventions included in-school comprehensive sexuality education, cash transfers, educational support, life skills training, livelihood training and community dialogue. Across the five countries, baseline scenario intervention costs were US$1.4 billion over 2024–2030, with a projected 2.4 million unintended adolescent pregnancies and 2.1 million child marriages among girls 15–19 years. Scale-up of all interventions to reach 95% coverage by 2030 would cost an additional US$5.0 billion and, in return, avert 1.3 million unintended pregnancies and 1.1 million child marriages. This was estimated to generate US$13.2 billion in economic benefits by 2050 with a benefit-cost ratio of 2.7, increasing to 9.7 if interventions were maintained to 2050 and lifetime benefits considered. Achieving a more modest 50% intervention coverage by 2030 produced similar benefit-cost ratios but with reduced total impact.Conclusion For every US$1 invested to scale up and maintain high coverage of evidence-based interventions to reduce child marriages and adolescent pregnancies in Cambodia, Indonesia, the Philippines, Lao PDR and Malaysia, US$9.7 could be returned to the economy in the longer term.
Abstract from DOAJ. Public domain (CC0 1.0).
Read the article at the publisher →
Wickramaarachchi, T., Habito, M., Beni, D., et al. (2026). Return-on-investment for interventions to reduce adolescent pregnancy and child marriage in Southeast Asia: a five-country modelling study. BMJ Global Health. https://doi.org/10.1136/bmjgh-2025-020106