Using Average Lifetime Dose Rate for Intermittent Exposures to Carcinogens

The effect of using the average dose rate over a lifetime as a representative measure of exposure to carcinogens is investigated by comparing the true theoretical multistage intermittent-dosing lifetime low-dose excess risk to the theoretical multistage continuous-dosing lifetime risk corresponding to the average lifetime dose rate. It is concluded that low-dose risk estimates based on the average lifetime dose rate may overestimate the true risk by several orders of magnitude, but that they never underestimate the true risk by more than a factor of k/r, where k is the total number of stages in the multistage model and r is the number of stages that are dose-related.     

The overuse of intrapartum cardiotocography (CTG) for low-risk women: An actor-network theory analysis of data from focus groups

BackgroundThere is an overuse of cardiotocography for intrapartum fetal monitoring for low-risk women in high-income countries, despite recommendations from evidence-based guidelines.AimTo understand why midwives use cardiotocography for low-risk women despite evidence-based recommendations and to understand the roles of the cardiotocograph machine.MethodThis qualitative study used focus groups for data collection. Thirty-one midwives and three student midwives participated from four different countries: New Zealand, Australia, Denmark, and Norway. Constant comparative analysis, informed by an actor-network theory framework, was the method of data analysis.FindingsCardiotocography was multifaceted and influenced all attendants in the birth environment. The cardiotocograph itself is assigned different roles within the complex networks surrounding childbirth. The cardiotocograph’s roles were as a babysitter, the midwives’ partner, an agent of shared responsibility, a protector that ‘covers your back’, a disturber of normal birth, and a requested guest.DiscussionThe application of the actor-network theory enabled us to understand how midwives perceive cardiotocography. The assigned roles of the cardiotocograph shape its everyday use more than evidence-based guidelines. Discussion of these inconsistencies must inform the use of cardiotocography in the care of women with low-risk pregnancies.ConclusionWe found that the cardiotocograph is a multifaceted actant that influences practice by performing different roles. Drawing on this study, we suggest that actor-network theory could be a helpful theoretical perspective to critically reflect upon the increasing use of technologies within maternity care.