Assessment of cognitive function across pregnancy using CANTAB: a longitudinal study

Significant changes in endogenous plasma hormone levels are required to sustain pregnancy which provides a unique opportunity to study their effect on cognitive function. Four carefully selected tests from the Cambridge Neuropsychological Automated Test Battery (CANTAB) were administered to assess the cognitive function of a group of 23 women during each trimester of pregnancy and at three months following birth. Test scores were compared with a control group of 24 non-pregnant women. The Edinburgh Postnatal Depression Scale was administered to assess anxiety and risk of depression. The National Adult Reading Test (NART) was used as a measure of verbal intelligence. Plasma hormone levels were measured at each time-point. The pregnant group scored significantly lower than the control group on the Spatial Recognition Memory (SRM) test at the second trimester and postpartum assessments (p⩽0.004). A significant pregnant group-time interaction (p=0.005) for SRM performance was demonstrated. Compared to their first trimester assessment, the pregnant group scored on average 11.7% less on each subsequent SRM test. The pregnant group reported more symptoms of anxiety and depression compared to the control group (EPDS-4 point increase in mean score at each assessment, p=0.002). There were no plasma hormone levels and test score associations identified. These data suggest SRM performance is adversely affected by pregnancy. Other aspects of executive function seem to be unaffected. Although the pregnant group reported more symptoms of anxiety and depression compared to the control group, analysis indicates that this confounder is not responsible for the SRM differences.