Objective To determine whether presenting delivery room management options as defaults influences decisions to resuscitate extremely premature infants. Materials and methods Adult volunteers recruited from the world wide web were randomised to receive either resuscitation or comfort care as the delivery room management default option for a hypothetical delivery of a 23-week gestation infant. Participants were required to check a box to opt out of the default. The primary outcome measure was the proportion of respondents electing resuscitation. Data were analysed (...) using χ2 tests and multivariate logistic regression. Results Participants who were told the delivery room management default option was resuscitation were more likely to opt for resuscitation (OR 6.54 95% CI 3.85 to 11.11, p<0.001). This effect persisted on multivariate regression analysis (OR 7.00, 95% CI 3.97 to 12.36, p<0.001). Female gender, being married or in a committed relationship, being highly religious, experiences with prematurity, and favouring sanctity of life were significantly associated with decisions to resuscitate. Discussion Presenting delivery room options for extremely premature infants as defaults exert a significant effect on decision makers. The information structure of the choice task may act as a subtle form of manipulation. Further, this effect may operate in ways that a decision maker is not aware of and this raises questions of patient autonomy. Conclusion Presenting delivery room options for extremely premature infants as defaults may compromise autonomous decision-making. (shrink)