This study extends Thaddeus and Maine's (1994) "three delays" framework to model the interrelated barriers to maternal health care and birth registration. We focus on stateless persons and irregular migrants, populations that are especially at risk of being "left behind" in United Nations member states' efforts to "provide legal identity to all" as part of the 2030 Sustainable Development Agenda. Drawing on qualitative fieldwork conducted in Sabah, Malaysia, we model delays in accessing maternal health care and birth registration as an integrated, cyclical process. We identify the political and legal barriers that stateless or migrant families confront while deciding to make institutional contact (Phase I), identifying and reaching health or registering institutions (Phase II), and receiving adequate and appropriate treatment (Phase III). We find that exclusion from one system raises the risk of exclusion from the other, resulting in a range of negative consequences, including increased health risks, governments' impaired ability to monitor population health, and the perpetuation of intergenerational cycles of legal exclusion.