Memory performance, but not information processing speed, may be reduced during early pregnancy

Several studies have investigated aspects of cognitive functioning during late pregnancy or in the period around delivery. The present paper describes a controlled study of neurocognitive functioning in an early phase of pregnancy (14 weeks). Seventy-one pregnant women and 57 control subjects matched for age and education were tested with a cognitive test battery. Intentional learning was tested with the Verbal Learning Test, retrieval from semantic memory with the Fluency Test, and speed of information processing with the Concept Shifting Test, the Stroop test, and the Letter Digit Substitution Test. Results show that performance on tests measuring intentional learning and retrieval from semantic memory were lower in the pregnant group during early pregnancy as compared to a closely matched nonpregnant group. In contrast, speed of information processing was not different between the two groups. The differences observed in memory performance were not large and further research is needed to establish their clinical significance. In addition, the results should be interpreted with care, because our study has a cross-sectional design, which has limitations concerning the fact that preexisting performance differences might be possible. Therefore, longitudinal studies are essential to ascertain clear associations between pregnancy and cognitive performance.