In the context of globalization, new technologies of pregnancy are spreading rapidly from affluent to low-income countries. Yet, to date, there is very little research on the application of prenatal diagnostic technology in developing country settings or the dilemmas that prenatal screening may give rise to in situations where health-care resources are scarce. In this article, we describe how obstetrical ultrasound scanning is used as the most important technology for prenatal diagnosis in Vietnam. We explore the social context that shapes moral sentiments and ethical deliberations within everyday medical interactions, drawing attention to the complex social processes through which ethical dilemmas are configured. The data include observations in the scanning room, and semi-structured interviews with patients and staff at a major maternity hospital in the country's capital Hanoi. We found that pregnant women received very limited information and support when a fetal anomaly was detected by ultrasound. Most women left the hospital feeling uncertain about what was wrong with the fetus and decision-making about abortion centred around the difficulties of parenting a disabled child in Vietnam. We conclude that the ethical problems surrounding prenatal screening are intensified in low-income settings such as Vietnam and point to the need for research that takes into account the wider social context that structures ethical dilemmas.