Publishing negative findings and the challenge of avoiding type II errors in studies of suspect teratogens: Example of a recent ondansetron publication.

It is important that negative, as well as positive, studies be published to complete the available picture in areas of scientific inquiry. At the same time, it is critical that the implications of a negative study not be overstated and generalized when major issues of study design and data accuracy may be the reason that no relationship was discovered. The challenge of avoiding type II errors in interpreting negative findings has major public health implications, especially when the relationship of an exposure to birth defects is the concern. This is particularly important when interpreting the report by Fazio et al. (June issue of Reproductive Toxicology) on the relationship of ondansetron exposure to pregnancy outcome and birth defects. This review addresses the study design and conclusions and suggests that an alternative concluding statement would be more apropos, given the limitations of the data.