['Yeah, you're pregnant all right! And he's beautiful!' The construction of 'truths' in obstetric ultrasonography].

Obstetrical ultrasound is a technology which has undergone a peculiar transformation. In Brazil what began as a medical imaging technology is progressively being transformed into a modality of consumption and 'leisure'. In this paper I discuss the production of 'truths'--founded on medical and non-medical beliefs about the 'objectivity' of medical imaging technologies--during obstetrical ultrasound exams. The discussion is based on ethnographic material obtained in private imaging clinics in Rio de Janeiro, Brazil. Ultrasound exams underscore the subjectivity/objectivity issue belonging to all medical imaging technologies, due to the peculiarity of being a dynamic and interactive practice. During an obstetrical ultrasound the actors are active agents in producing or reproducing medical and non-medical 'truths' about the pregnancy and the fetus. Those 'truths' play a central role simultaneously reconfiguring the pregnancy, subjectivizing the fetus, and transforming a medical practice into a spectacle. This production acts as a feedback mechanism, reassuring the actors about the healthy state of the pregnant woman and the fetus as well as reaffirming the position of medical imaging technologies as privileged producers of truths about the human body.