Fundamental study of functional changes to female brain induced by pregnancy and childbirth

In this study, we investigated variations in a women's cognitive function during a time of pregnancy and childbearing. Volunteers were composed of 114 healthy women ranging in age from 23-43 years with an average age of 31.8 years (SD=4.3). Further, 79 were pregnant and 35 were not pregnant. All the pregnant women were expecting their first child and continued with the cognitive function analysis after their childbearing was concluded. We instructed the pregnant women to carry out five kinds of tests: simple reaction, SR; choice reaction, CR; working memory, WM; one card learning, OC; and divided attention, DA using card games through a cognitive function test called "CogHealth", and compared them to a nonpregnant group. In the results of the four measurement tasks (SR, CR, WM, and DA), there were no significant differences across the three groups in the responses with the tasks. However, the response times relating to the OC learning in the postnatal women were significantly smaller, as contrasted with the times for the pregnant and the nonpregnant women (F(2,144)=4.248, P <; 0.05). Furthermore, we compared their cognitive functions between pregnant and postnatal states in corresponding volunteers in the responses with the same tasks. We also demonstrated the fact that postnatal women responded more quickly to tasks in the OC (t(32)=2.95, P <; 0.01) and the WM (t(32)=3.03, P <; 0.01) categories than responses to performing the tasks during their pregnancy. Our findings support the idea that the functions of pregnant/postnatal women are not failing, or rather postnatal women are more responsive in their reaction times with their memories by 2.7-6.2%, than the responses in both pregnant and nonpregnant women.