Retrospective collection of data on maternal substance use during pregnancy has been considered less accurate or precise than concurrent reports by some investigators. However, comparison of prospective and retrospective data for drinking during pregnancy has shown retrospective data to be valid (Griesler and Kandel, 1998). Furthermore, some evidence suggests that retrospective report may actually be more valid among women reporting heavy alcohol use (Czarnecki et al., 1990). Women tend to report higher levels of alcohol use during pregnancy retrospectively than concurrently (Ernhart et al., 1988, Jacobson et al., 1991), indicating that concurrently reported alcohol consumption during pregnancy is probably under-reported (Alvik et al., 2006). Furthermore, retrospective reports acquired fourteen years postpartum have been shown to relate to significantly more birth and teen outcomes than antenatal report (Hannigan et al., 2010).
