Postpartum Depression

Although a number of studies have reported on antenatal factors associated with postpartum depression, the samples used have usually been too small to derive a reliable predictive index. By the end of the twentieth century the only large-scale predictive study conducted revealed that the most reliable predictors of postpartum depression—such factors as the absence of social support or a previous history of depression—each approximately doubled the odds over the base rate risk (Cooper et al. 1996). The predictive index derived from this study is somewhat useful: at a cutoff score of twenty-six about a third of those who will develop postpartum depression are identified, and about a third of those scoring above this cutoff become depressed. It is unlikely, given the modest elevation of odds conferred by all antenatal risk factors identified to date, that an antenatal predictive index could be produced with substantially better predictive power.

The prediction of postpartum depression could probably be improved if account were taken of certain postpartum factors. For example, a study that examined the impact of early postpartum factors on the course of maternal mood (Murray et al. 1996b) found that, beyond the predictive contribution of antenatal factors, both a high maternity blues score and certain neonatal factors (infant irritability and poor motor control) were significantly related to the onset of postnatal depression. Because both the maternity blues and the neonatal infant factors contribute predictively over and above antenatal variables, the predictive value of critical antenatal factors could be improved by taking account of these postpartum variables.