Inequity of maternal-child health services in ASEAN member states from 1993 to 2021

Introduction Inequity in maternal-child health services is a challenge to global health as it hinders the achievement of Sustainable Development Goals (SDGs) and Universal Health Coverage. Though the Association of Southeast Asian Nations (ASEAN) has made remarkable achievements in maternal-child health, there remain gaps in reaching global goals. This study aimed to compare and investigate the inequity in maternal-child health (MCH) services in ASEAN member states to help guide policy decisions to improve equitable health services in the SDG era and beyond. Methods Using the WHO Health Inequality Monitor, we identified inequity summary measures for five MCH services in ASEAN member states from 1993 to 2021: antenatal care, births attended by skilled health personnel, diphtheria, tetanus and pertussis (DTP3) immunization, measles immunization, and polio immunization. We divided the analysis dimension of inequity into urban–rural inequity, economic status inequity, and sub-regional inequity. Trends of absolute and relative inequity in every dimension of MCH services in ASEAN member states were examined with the principal component analysis (PCA). Results The mean coverages of MCH services are 98.80% (Thailand), 86.72% (Cambodia), 84.54% (Viet Nam), 78.52 (Indonesia), 76.94% (Timor-Leste), 72.40% (Lao PDR), 68.10% (Philippines) and 48.52% (Myanmar) in 2021. Thailand have the lowest MCH services absolute inequity indexes of -1.945, followed by Vietnam (-1.449). Lao PDR and Myanmar have relatively higher MCH services absolute inequity indexes of 0.852 and 0.054 respectively. The service in Cambodia, Indonesia, and the Philippines is pro-specific regions (with subnational region absolute inequity indexes of -0.02, 0.01, and 1.01 respectively). The service in Myanmar is pro-rich (with economic status absolute inequity index of 0.43). The service in Lao PDR and Timor-Leste is pro-urban areas, pro-rich, and pro-specific regions. Conclusion The inequity of MCH services in ASEAN persists but is in a declining trend. Thailand and Vietnam have performed well in ensuring MCH services equity, while Laos and Myanmar are still facing serious inequity dilemmas. The progress of MCH service equity in Myanmar, Cambodia, the Philippines, and Indonesia is uneven. It is acceptable to learn from the successful experiences of Thailand and Vietnam to improve the equities in other ASEAN countries. Policies should be developed according to the specific types of MCH inequity in member states to improve equity levels. Supplementary Information The online version contains supplementary material available at 10.1186/s12939-023-01974-8.