Objectives <p>Some studies indicate cognitive defects during pregnancy, but the factors affecting these defects have not been addressed. Therefore, the present study aims to determine the impressive factors in executive function during pregnancy.</p> Materials and methods <p>This study was conducted on pregnant women referred to Imam Hossein and Taleghani Hospital in Tehran between October 2019 and October 2021. Eligible people completed the Brain Executive Function Questionnaire of the adult self-report form at the following three points of follow-up: the first trimester of pregnancy, the third trimester of pregnancy, and postpartum. The executive performance scores of the studied subjects and the influencing factors were reported.</p> Results <p>In this study, 210 pregnant women with a mean age of 28.70 ± 7.08 years filled out the questionnaire three times. The Global Executive Composite (GEC) of the study subjects in the third trimester of pregnancy was significantly higher than in the first trimester of pregnancy and after delivery (a higher score indicates a greater impairment of the brain’s executive function), which indicates lower executive function during the third trimester. The GEC of the study subjects after delivery was significantly higher than in the first trimester of pregnancy. The level of education of the subjects was the covariate of the changes in the study subjects’ executive performance.</p> Conclusion <p>Score of the postpartum period in comparison to the first trimester was significantly decreased, yet. Also, the changes in the executive function of the brain during pregnancy were influenced by the level of education, including better function and lower decline in the high-educated group.</p> Graphical Abstract <p></p>