Cognition in pregnancy and the first year post-partum.

A longitudinal study measured the performance of a group of 15 pregnant women on tests of verbal memory, divided attention, and focused attention on four occasions (second trimester, third trimester, 6 weeks post-partum, and 1 year post-partum) while at the same time obtaining self-assessment ratings of these cognitive functions. A group of 14 non-pregnant women was studied at equivalent intervals. The two groups of women did not differ in performance on the objective tests, and there was no change in performance over time except for an improvement in the measure of focused attention from the first to the final testing occasion. However, the self-assessment ratings showed that in the second trimester, the pregnant women rated themselves as more impaired than before compared with the non-pregnant women for all three cognitive abilities. To ensure that this difference was not due to the retrospective nature of the comparison of current with previous cognitive ability, a second longitudinal study compared 25 pregnant and 10 non-pregnant women using daily ratings over a period of 1 week on four occasions during pregnancy and the first year post-partum. Women in the third trimester of pregnancy reported mild impairments in their focused and divided attention ability and their ability to remember what they had read compared with the non-pregnant women. The results show that there are perceived cognitive impairments during pregnancy. It is suggested that these may be the result of mild impairments which are not revealed in objective tests because they can be overcome by conscious effort in short periods of testing. Alternatively, the perceptions may not be based on actual impairments but may result from depressed mood or expectations concerning the effect of pregnancy on cognition.