This study was a prospective cohort study including pregnant women referred to Imam Hossein and Taleghani Hospitals in Tehran between October 2019 and October 2014.
Study inclusion and exclusion criteria
The inclusion criteria were:
Pregnant women referring to the prenatal care (PNC) clinic of Imam Hossein and Taleghani Hospitals in Tehran in the first trimester of pregnancy which was confirmed with the β-hCG test, enrolled in the study. ability to read and write, absence of comorbidities such as hypertension, diabetes, and cardiovascular diseases, and systemic diseases such as lupus and epilepsy, and no history of IVF method, addiction to smoking, alcohol, and psychotropic drugs included in the study.
The exclusion criteria were as follows: The exclusion criteria for the study were the occurrence of severe hyperemesis gravidarum (to the extent that led to hospitalization). People who got pregnant with ART methods, people who were known cases of psychiatric diseases, or had addictions to smoking, alcohol, and psychotropic drugs were excluded from the study.
Patients who developed severe preeclampsia during the study, cases of GDM leading to hospitalization and treated with insulin, and all cases of abortion were excluded from the study.
Also, people who dropped out of follow-up for various reasons are reported as lost follow-up after several phone calls.
Sampling method, sample size, and how to calculate it
In this study, the convenience sampling method was used. The sample size based on the data extracted from previous studies considering the power of 0.8 and the type 1 error of 0.50, and considering the drop of 20%, was 210 subjects.
Method
In this study, the changes in the executive function of the brain in 210 pregnant women were measured. Each of the samples was followed up three times including the first trimester of pregnancy, the third trimester of pregnancy, and the postpartum period (the 42nd day to 2 years after delivery). The last visit was not conducted within 42 days after the delivery. After giving complete explanations about the study to the subjects, written informed consent was obtained. Basic data of the study population was recorded in checklists including data such as age, level of education, gestational age, height, and weight. The tool used in the research was a self-report questionnaire that was completed three times as mentioned above.
Study tool
The main international questionnaire used in this study was the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A), which has been translated and localized under the name of the Brain Executive Function Questionnaire, a self-report form of adults. The BRIEF is a daily executive functioning test developed by Juvia in 2000 for parents and teachers of elementary school-aged children, preschoolers, and then adults. All 75 questions of the adult questionnaire have the same score. The scoring of the questions was based on a three-point Likert scale from 1 (never) to 3 (often). The adult questionnaire has three main indexes: the List of Behavioral Regulation Inventory (BRI) which measures the ability to control behaviors and impulses; the metacognitive index (MI) which measures functions related to maintaining attention and working memory and organization; the Global executive composite of the brain (GEC) that shows the overall level of executive functioning. BRI includes four scales (inhibition, change, emotional control, and self-monitoring) and MI includes five scales (initiation, working memory, planning/organizing, monitoring of tasks, and material organization)(46). Table 1 shows the questions related to BRI and MI and related scales. To evaluate the validity of completion of the questionnaire completed by each person three indicators of negativity, infrequency, and inconsistency were used. To analyze BRIEF-A, T Score (M=50 and SD=10) was used. These scores are changes in raw scale scores. The Persian version of the questionnaire was evaluated by Mohammadnia et al. in 2020 and it had acceptable validity and reliability(47).
SPSS/23 statistical software was used for data analysis. Mean, standard deviation, frequency, percentage, mean difference, and 95% confidence interval were used to describe the data. The paired t-test was used to compare the scores of the questionnaire at different time points. Analysis of variance with repeated measurements and follow-up tests were used to investigate the time trend of changes in executive function and the effect of various factors on it. Multivariate linear regression was also used to determine predictor variables of executive performance. All tests were performed at a significance level of 0.05.
Ethical considerations
This study was carried out after the approval of the ethics committee of Shahid Beheshti University of Medical Sciences (Ethical code: IR.SBMU.MSP.REC.1401.495). In all stages of the study implementation, the identity of any of the participants has not been revealed. The information of the subjects of the study is only at the disposal of the researchers and the data is published collectively. All the participants in the study, after providing sufficient explanations, completed the informed consent form. This study was conducted in compliance with the 2000 Declaration of Helsinki.