RESUMEN
Owing to a growing policing of borders, healthcare professionals become increasingly involved in the biopolitical management of migrants' mobility. While their presence on sites of migration control and detention is necessary to ensure migrants' access to healthcare, their role risks being instrumentalized to ensure the sustainability of detention and swiftness of deportations. This article analyses the practice and ethics of midwives' medical expertise in processes of migration control in the French overseas department of Mayotte in the Indian Ocean. Midwives in this setting are required to assess the health of pregnant women intercepted at sea by the police in order to determine whether they can be detained. The article traces how midwives come to be invested with a power to police patients' mobility. In the face of such unwelcome responsibilities, midwives resorted to emotional distancing while suspicion on both sides impeded the possibility of genuine relations of care. The article analyses how midwives framed the ethical dilemmas at hand and examines how they perceived their decision-making responsibility. I argue that midwives are socialized into the logics of border enforcement and gradually brought to implement a minimal version of care as a result of migration control's inroads into care. The article thus questions the function and meaning of biopolitics within migration control and aims at initiating a conversation around the necessary conditions for ensuring medical personnel's independence in these extraordinary care settings. The article draws on a three-months fieldwork completed in Mayotte between mid-April and mid-July 2017 during which I conducted 40 interviews with healthcare professionals in perinatal health services and 15 interviews with officers from stakeholder organizations, from local and international NGOs to health institutions. This article draws in particular on interviews with the medical team that was required to attend to migrant women intercepted at sea by the police.