Depression in pregnancy “strongly predicts” depression postpartum: Are we inadvertently misleading clinicians and researchers?

Background: Many perinatal mental health risk factor studies report that antenatal depression is a signifcant risk factor for women being depressed postnatally. They often describe the strength of the risk as being ‘strong’ or ‘strongly predictive’ (or similar phrases), though usually without explaining why these terms are used. It is possible that readers of such research may misunderstand these qualitative descriptors. Method: As part of routine teaching regarding risk analyses, we explored participants’ understanding of the conclusion stated in one specific perinatal risk study, which was that antenatal depression “strongly predicts” postnatal depression. Participants were groups of mental health professionals and postgraduate students, in Italy (N = 56) and Australia (N = 34).They completed an Estimate Survey, in which they indicated the actual number of antenatally depressed women they expected would have been depressed postpartum, given the study's conclusion. Results: The majority of survey respondents (~80%) expected that “strongly predicts” meant that a much higher proportion of women with the risk then became depressed than was actually the case. Some participants expressed major concern at the study's conclusion. Limitation: Participants comprised two small convenience samples of health professionals and postgraduate students, and thus may not be representative of the population. Conclusion: Studies that rely on the statistical significance of their analyses to conclude whether antenatal depression is a strong predictor or risk for postnatal depression may not accord with how health professionals interpret the data, once the absolute risk information is clearly provided. Recommendations for improving the reporting of results in such studies are made.