Development and Psychometrics of a Theory-Based Physical Activity Assessment Questionnaire for the Pregnant Women (PA2Q-PW)

Backgrounds & Aims: There is evidence that physical activity plays an essential role in preventing pregnancy-related diseases. This study aimed to develop and design a theory-based physical activity assessment questionnaire for pregnant women (PA2Q-PW). Methods: The PEN-3 cultural model provided the theoretical foundations for the four subscales of our designed instrument; knowledge, attitude, nurture, and enabling. The primary questionnaire was designed with 41 items, and the questionnaire was modied according to the experts' reviews. At last, a group of 400 pregnant women participated in a study to calculate the psychometrics of the tool. Results: The highest score was seen in the knowledge subscale of PA2Q-PW, and the value of Cronbach's alpha for the subscales was from 0.89 to 0.97, and the value of ICC was from 0.76 to 0.89. The correlation (CVI & CVR indices) between the experts was satisfactory in all items of PA2Q-PW. The minimum loading factor for varimax rotation in the knowledge subscale was 0.41; the attitude was 0.56, nurtures were 0.38, and enabling was 0.27. Conclusion: PA2Q-PW is the rst standard tool based on the PEN-3 cultural model that researchers can utilize to gather data and conduct the desired education interventions to change physical activity behavior in pregnant women during pregnancy.


Introduction
Pregnancy is an astonishing period of life for a pregnant woman and her unborn infant [1]. There is evidence that physical activity plays an essential role in preventing preeclampsia, type 2 diabetes, obesity, and many cancers [2]. Also, it has further advantages during pregnancy and diminishes the risk of HELLP syndrome, gestational diabetes mellitus, and additional gestational weight gain [3,5]. Having physical activity is also one of the substantial factors affecting the quality of life. Nowadays, It has increasingly speci ed that assessing the quality of life can predict the health situation in various groups [13,15].
In the United States, in lack of obstetric complications, as per the guidelines of adults, pregnant women must accumulate 30 minutes or more of moderate-severe physical activity on most, all the days a week [6,7]. The American College of Obstetrics and Gynecology (ACOG) suggested a 30min program of physical activity ve days a week for pregnant women [8]. Along with dieting, having activity during pregnancy promises a natural and impressive intervention for infant and maternal health [9,10]; however, some Iranian pregnant women seem not to follow these guidelines, and a study in Iran showed that 70% of pregnant women did not have any physical activity [11,12].
One of the approaches to increase physical activity for a lifetime is to use theoretical research to recognize the in uences of physical activity on pregnancy theoretically. The lack of success in many exercise promotion endeavors may be due to the lack of recognition of theory-based determinants of health [16]. Some theoretical derivative tools measure the determinant factors of physical activity among pregnant women presented in the literature [21]. PEN-3 cultural model is a theory that has been exerted in a study of physical activity determinants in pregnant women [17,20]. Nevertheless, there are no general validated scales to measure perceptions and nurtures and enable pregnant women to exercise during pregnancy. Thus, the designed tool could help to comprehend women's prospects for physical activity and, in turn, plan available interventions for pregnant women. It has been shown that people who recognize themselves as physical activists have more intentions in and employ considerably more physical activity than people who do not [22,23]. In the United States, 25% of people do not exercise in their workplace, and 12% of total mortality was attributed to low mobility [24]; however, this study was limited to a group of nulliparous pregnant women. The information from Iran shows that the outbreak of no mobility and inactive lifestyle in males is less than that of females [25,26]. Sarrafzadegan et al. realized that abdominal obesity was approximately six times more in females than males [27].
According to the need of developing a questionnaire to evaluate psychosocial and perceptual determinants of physical activity in different levels of pregnancy, this study aimed to develop and design a theory-based physical activity assessment questionnaire for pregnant women (PA2Q-PW) based on the PEN-3 cultural model.

Qualitative Section
The PEN-3 cultural model provided the theoretical foundations for the four subscales of our designed instrument, knowledge, attitude, nurture and enabling. These subscales were designed according to "beliefs about the consequences of participating in physical activity", "attitude toward the behavior", and "nurtures of others" components of the PEN-3 cultural model [28].
The primary questionnaire was designed with 41 items and was evaluated by 12 experts in health education and health promotion, gynecology, and physical activity. The items on the questionnaire were modi ed according to the experts' reviews.
In the next step, 20 experts on health education and health promotion were independently requested to assess the necessity and relevance of the questions. The necessity of the questions was evaluated using a three-point scale, "not necessary", "effective but not necessary", and "necessary". The Content Validity Ratio (CVR) was calculated for all items, and if more than half of the panelists represent that an item is necessary, that item was considered to have the minimum content validity [29]. The relevance of the questions was also evaluated using a four-point scale, "not relevant", "insigni cantly relevant", "relevant", and "reliably relevant". The Content Validity Ratio (CVI) was calculated for each item [30,31].
The instrument went through three pilot tests conducted in one health center in Tehran City, Iran. These three steps were performed on nulliparous pregnant women selected by similar criteria to the main study population. The initial pilot test indicated that pregnant women had di culty understanding some items, tiny words for reading, and lengthy questionnaire sentences. Changes to the primary instrument during the rst pilot test included selecting short appropriate words and putting the instrument in a visually more appealing format (giant print, more full margins). The subsequent two pilot tests re ned and reduced the size of the items that pregnant women did not understand. The administration time of the nal instrument was about 20 minutes. Quantitative Section a cross-sectional study was performed in health centers of Tehran City, Iran, from January to March 2019.
The sample size was estimated at 342 by Cochran formula (Con dence=0.95, Power=0.9), and to compensate the loss, 400 nulliparous pregnant women in two or three trimesters of pregnancy that were between 28 to 35 years, having literacy, have no background of severe complications of the disease, and without any physical activity during pregnancy were selected randomly from selected health centers of the 5 th district of Tehran City, Iran.
The questionnaires were lled whenever the midwives stayed in the health centers. Evaluations were accomplished anonymously, and nulliparous women had the choice to skip any item using the choice "I choose not to answer". If a sample responded to less than 80% of the questions or items on a subscale or scale, the total score was not computed for that variable. Based on the information provided on these criteria, less than 5% of nulliparous women were missing measure grants for particular variables.
The Ethics Committee of Tarbiat Modares University approved the study. All the pregnant women's written consent was taken, and they could withdraw from the study at any time they wished. All records were preserved private, and the researcher and other staff did not use such records and information for any target other than operating the survey. Pregnant women and their husbands were told at the beginning of each assessment that their responses were con dential and did not have access to each other's answers.

Validity
The different dimensions of the criterion were speci ed by implementing exploratory factor analysis (EFA) to apply the oblique rotation and original fundamental factoring [32][33][34]. Varimax rotation with Kaiser Normalization was chosen as the correlation between factors was less than 0.3 [35]. Kaiser-Meyer Olkin (KMO) and Bartlett's test were calculated [36]. The values of correlation of 0.40 or higher were considered satisfying (r ≥ 0.81-1 as supreme and excellent, 0.61-0.80 as excellent, 0.41-0.60 as good, 0.21-0.40 as fair, and 0.00-0.20 as poor) [37].

Reliability
The reliability was calculated by the intraclass correlation coe cient (ICC) by a one-month interval (0.0-0.20 as low, 0.21-0.40 as fair, 0.41-0.60 as moderate, 0.61-0.80 as signi cant, and 0.81-1 as nearly complete and perfect) [37]. Also, the internal consistency of PA2Q-PW was accounted for by calculating Cronbachs' alpha coe cient. The alpha amount of 0.70 or higher was noticed as satisfactory [37].

Results
The average age of participants was 32.4±12.4 years, the average BMI was 26.80±6.25, and they had week exercise within gestation (Table 1). The correlation (CVI & CVR indices) between the experts was satisfactory in all items of PA2Q-PW (Table  2). *These items were omitted The highest score was seen in the knowledge subscale, and the value of Cronbach's alpha for the subscales was from 0.89 to 0.97, and the value of ICC was from 0.76 to 0.89 (Table 3).    The con rmatory factor analysis results for the four sections of the PA2Q showed a χ 2 value at 3921.78; degrees of freedom 1117, which gave a ratio χ 2 /dF=3.51 (p<0.0001). The CFI, NFI, GFI's, and RMSEA values were 0.90, 0.80, 0.92, and 0.091, respectively (p<0.0001). Figure 1 shows the factor weighting value results for the four Knowledge, Attitude, Nurtures, and Enabling subscales in the standard estimation mode.
The minimum loading factor for varimax rotation in the knowledge subscale was 0.41, the attitude was 0.56, nurtures was 0.38, and enabling was 0.27 (Table 5). If there is a group discussion to exchange information about pregnant women after a pregnancy class, I have a greater tendency to attend a pregnancy class.

0.38
If a skilled and informed person answers midwifery questions after a pregnancy class, I would be more eager to participate in pregnancy classes.

0.77
If my doctor advises me to do exercise in pregnancy, I will do that. proposed that for direct scales, one could use the similar direct scales designed by Airhihenbuwa [35]. Regarding indirect (based on perceptions) scales, it has been suggested to accomplish an exploitation study to design all of the constructs about predictive factors in the PEN-3 that consist of knowledge, attitude, nurture, and enabling. In this research, various assumptions were created due to direct and indirect views about the fundamental cognitive structures, and neither view is complete. When several procedures are knapping a similar construct, degrees are anticipated to be a rmatively associated, so it is suggested that both contain a PEN-based questionnaire [35]. Unfortunately, only direct scores of the theory-based PEN-3 cultural model were used in this study.
For the perceptions, nurtures, and enabling factors, the development sample's internal consistency of reliabilities was above 0.80. For the perceptions, nurtures, and enabling factors, the test-retest correlation coe cients were about 0.90 in the Intended sample. These rates are checked su ciently [37]. Regarding the attitude scale, the correlation coe cients and internal consistency for reliability were slightly mitigating.
This survey used a changeable approach more acceptable for pregnant women. As well as the internal consistency of reliabilities was higher than those received in primary function with rst pregnant women that contained perceptions toward consequences [38]. It also should be distinguished that the reliability for the retest-retest in this survey was managed immediately after the rst data collection. In this study, the ICC for full scale about physical activity was 0.92, and it shows higher than was used questionnaire those obtained in previous work with pregnant women [38].
This survey's further contributions were used to validate the questionnaire construct and Chartered Financial Analyst (CFA) method, which can be exerted to trial numerous variables while there is a theoretical framework [39]. Moreover, various indicators, such as χ 2 /dF ratio, CFI, GFI, and RMSEA, veri ed the compatibility of the models. The results regarding the (NFI, RMSEA, and CFI) were higher than expected. Additionally, this nding demonstrated that each of the four sub-constructs in the PA2Q t appropriately within the PEN-3 cultural model framework.  [42].
Therefore, according to the authors, the PA2Q is suitable for various potential applications to measure physical activity and its main determinants among pregnant women. Besides, the PA2Q tool may be used with other grade populations and suitable for Non-pregnant women. One unique feature of PA2Q is the reliability and validity of its subscales, which include knowledge and attitude, nurtures, enabling, and physical activity behavior. These sub-constructs may be measured, evaluated, modi ed by potential change strategies, thereby doing physical activity during pregnancy and, nally, health promotion. Some limitations of this study must be noted. First, data were only collected from the two and threetrimester pregnant women attending health centers in capital Tehran's region 5; and other independent health centers, other gestational ages during pregnancy, did not enroll to study the generalizability of results to all of the society may be con ned. Due to decreased recall bias, the physical activity report was limited within the last week. Subscales of the PA2Q were limited to the main determinants of behavior in the PEN-3 cultural model, and the other constructs (psychological determinants of behavior) to decrease the questions' burden on participants did not use. In the nurture items construct validity veri cation phase, the sample was limited to pregnant women and not their families because of the di culty of assessing. Notwithstanding the limitations explained, the PA2Q is the instrument of validity and reliability to assess women's exercise behavior through pregnancy. Future studies that apply this questionnaire could assist and help to overcome this kind of problem. Conclusion PA2Q-PW is the rst standard tool based on the PEN-3 cultural model that researchers can utilize to gather data and conduct the desired education interventions to change physical activity behavior in pregnant women during pregnancy. The PA2Q-PW was demonstrated to be consistent and reliable within its knowledge, attitude, nurtures, and enabling subscales. However, future attempts are carried to assess whether PA2Q-PW is applicable in the rst trimester of pregnancy in pregnant women populations attending various community-based settings, including the health services center.

Declarations
Modares University for its nancial support. This study was a part of the rst author's doctoral dissertation in health education and promotion at the Faculty of Medical Sciences, Tarbiat Modares University. It was approved by the university's institutional review board (IRB) on August 18, 2018. We wish to acknowledge the assistance and support of authorities and faculty members in the Faculty of Medicine and Tarbiat Modarres University. The authors would like to thank the Ministry of Education and District ve authorities and staff in Tehran for implementing the project. A preprint has previously been published [43].
Ethical approval: The Research Ethics Committee of Tarbiat Modares University approved the research of this study. All pregnant women in this trial were informed about participating in the survey, and written informed consent was taken.