An implementation trial of continuous quality improvement for antenatal syphilis and HIV detection and treatment in Indonesia: The MENJAGA study The dual elimination of mother-to-child transmission (EMTCT) of HIV and syphilis through screening and treatment of pregnant women has been identified as a global public health priority. Indonesia has set an ambitious EMTCT target of 2030. Currently, only 27% of pregnant women are tested for HIV and 1% for syphilis (using a mixture of rapid tests and laboratory-based testing), this is despite 98% of pregnant women attending antenatal care at least once during pregnancy. Moreover, only 48% of those testing positive for HIV and 30% for syphilis receive treatment. This poses a formidable challenge and is recognised as one of the most significant gaps in antenatal care in Indonesia. Persistent barriers to antenatal screening for HIV/syphilis include (but are not restricted to): limited awareness among health workers of the need for universal screening; some women are fearful of the test; lack of local standard operating procedures at the clinic level; supply chain gaps in tests and treatments; problems with the referral processes; and difficulties tracking women as they move across the health system. Context-specific interventions to better support the integration of HIV and syphilis testing and treatment into the Antenatal care (ANC) platform are urgently needed in Indonesia. Continuous Quality Improvement (CQI), which involves local ANC teams systematically collecting and reflecting on local data to inform the design and implementation of service delivery, has been effectively used to strengthen ANC services in a number of Sub-Saharan African countries. This approach holds considerable promise for Indonesia, a highly populous and diverse country where a 'one size fits all' approach to the delivery of quality ANC rarely applies. Using a  cluster-randomised design, we will evaluate the effectiveness, cost-effectiveness, acceptability, fidelity and reach of a multi-faceted CQI intervention to improve antenatal testing and treatment of HIV and syphilis in public and private ANC clinics in 6 districts across 3 Provinces (West Java, South Sumatra and South Kalimantan). This 3-year multi-disciplinary study will involve clinicians, epidemiologists, economists, social scientists, health services researchers and policy-makers from the Indonesian Ministry of Health (research partner), the London School of Hygiene & Tropical Medicine, the Universitas of Gadjah Mada, the University of Sebelas Maret and the Kirby Institute. A range of other stakeholders will be involved throughout the study (e.g. patient advocacy groups; implementing agencies; specialist professional associations; clinics and ANC services) to assess the appropriateness and acceptability of the intervention and barriers and facilitators to scale up. This research has the potential to contribute significantly to improved maternal and child health in Indonesia while also strengthening the underlying health system. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.