In this study, using a qualitative and quantitative approach, a valid, reliable, and practical questionnaire was developed for assessing the quality of life of women with GDM (GDMQ–36). In this questionnaire, the quality of life of mothers with GDM was influenced by concerns about high-risk pregnancy (11 items), perceived constraints (8 items), complications of GDM (6 items), medication and treatment (5 items), and support (6 items).
One of the most important factors in GDMQ–36 questionnaire is high-risk pregnancy related concerns, which claimed the highest percentage of variance among the tool’s factors. Most of the items in this factor are concerns about the fetal health or baby health, and the most frequent factor load is the concern about the premature birth and reduced fetal movements. In various studies, concerns about neonatal health before and after birth such as preterm labor or constraints on fetal development and mortality have been raised and most of the mothers are mainly concerned about the fetal and neonatal health (30–32).
Another factor of the GDMQ–36 questionnaire was perceived constraints. The most frequent factor load in this factor was dietary constraints including limited diet diversity and constraints on favorite fruits and foods. In the qualitative study, most participants found it confusing and frustrating that they could only eat a very small portion at once, or could not eat particular fruits at all which they enjoyed prior to being diagnosed with GDM(33). These constraints are specific to mothers with GDM who have to follow a special diet and the treatment to maintain their own and the fetal health. Such constraints can affect the quality of life of mothers with GDM. Among other constraints in GDMQ–36 questionnaire are sexual constraints which can affect the quality of life of mothers with GDM. Hyperglycemia can result in elevated serum prolactin levels and lead to neurotransmitter changes, which are potentially related to sexual dysfunction. Other causes of sexual dysfunction in these women may be the stress and anxiety sufferance because of GDM diagnosis(34).
Another factor in GDMQ–36 questionnaire is the disease complications including physical and psychological complications. Complications of gestational diabetes are the negative changes in various aspects of the person’s health caused by the disease, which can reduce the mothers’ quality of life. Due to the multidimensionality of quality of life, poor physical and mental health can affect the quality of life. The most frequent factor load in this factor was related to physical complications such as thirst and dry mouth and frequent urination. In a study examining the clinical and laboratory symptoms of glucose tolerance, over-hydration and frequent urination were the most important findings (35).
Another factor in GDMQ–36 questionnaire is medication and treatment. When the blood glucose cannot be controlled by diet, mothers have to administer insulin injections. The most frequent factor load in this structure was the problem of insulin injections. Repeated and timely injections of insulin, and frequent blood glucose tests in the laboratory or by a glucose meter require time management and can affect the mothers’ quality of life. In a study, most participants felt that they were controlled by the diabetes and they are entrapped in a compulsory lifestyle. This compulsory life-style involved continuous monitoring of blood glucose, insulin infusion, and insulin dose adjustment (36). This change in the lifestyle that is unfamiliar and sometimes unwanted can affect the quality of life of mothers with GDM. This has been considered in the domain of medication and treatment of GDMQ–36 questionnaire.
The last factor in GDMQ–36 questionnaire is support. The most frequent factor load in this factor is the empathy of the intimates and full support of the spouse. The support of friends and family members for mothers with GDM is effective in choosing a healthy lifestyle (37). In the study of Han et al., the first requirement for mothers with GDM to face the disease problems was the family or spouse support(38). Therefore, the domain of support in GDMQ–36 questionnaire may improve the quality of life of mothers with GDM.
Evaluating and recording health-centered quality of life based on quality of life assessment questionnaires has been of great importance. In previous studies, only general quality of life assessment questionnaires such as SF–36 and WHO-QOL-Bref have been used to assess the quality of life of mothers with GDM (9–11). Factor Comparison of GDM–36 questionnaire with general questionnaires suggested that GDM–36 factors are similar to some aspects of WHOQOL-Bref(39) and SF–36 (40), especially the mental and social health aspects. Although some of the items in GDMQ–36 questionnaire are consistent with the general questionnaire, the nature of the items in the general questionnaire is different from that of the questionnaire developed in this study. Specifically, the items in GDMQ–36 questionnaire are all in the context of GDM, but the items in the general questionnaires are designed in a way to be applicable to all communities. Public questionnaires (such as SF–36) are designed with no regard to the unique experiences of pregnancy. Although there are studies that show the adequacy of these questionnaires for different communities, their adequacy for the pregnant population has not been determined (12). In their study, Otchet et al. stated that the SF–36 health questionnaire of pregnant women has some constraints (41).
Other specific questionnaires, in this regard, include the pregnant women’s quality of life and diabetes’ quality of life questionnaire.
The pregnant women’s quality of life questionnaire (QOL-GRAV) is an instrument with 9 questions originally developed in Czech Republic. According to its designers, it is a supplementary tool for the general quality of life questionnaire of World Health Organization (WHO) (14). Comparison of this tool with GDM–36 questionnaire revealed that QOL-GRAV could not be potentially suitable for the quality of life assessment of mothers with GDM as it ignores many concerns and constraints which can affect the quality of life of mothers with GDM. In thin questionnaire, there is only one question, i.e. “How concerned are you about carrying a successful pregnancy? “that can be partly consistent with the domain “Concerns about high-risk pregnancy” in GDM–36 questionnaire. Another questionnaire on pregnant women’s quality of life has been developed in Iran which includes 65 questions in three domains of physical, psychological, and social problems; concern and worries; and adaptation(13). During pregnancy, physiologically due to hormonal changes, some physical or psychological complications occur in pregnant mothers. These issues have been addressed in this questionnaire, but the complications assessed in GDM–36 are the result of the increased or decreased blood glucose levels. The domain of concerns and worries in the pregnant women’s quality of life questionnaire, in some cases, were similar to concerns about high-risk pregnancy in GDM–36 questionnaire. However, in the pregnant women’s quality of life questionnaire, most concerns were about childbirth than the fetal health, as pregnant mothers’ quality of life questionnaire is only suitable for mothers who have a healthy and safe pregnancy.
Audit of Diabetes-Dependent Quality Of Life (ADDQOL) is a 13-item questionnaire developed by Bradley et al. (15). Also, Diabetes Quality of Life (DQOL) questionnaire has 16 questions developed by Lee et al. (16).Since diabetes is a chronic disease and can have a major impact on the social dimension and long-term consequences on the life of the patients, the questionnaire questions are more about social problems or long-term concerns of the disease. Therefore, these questionnaires may not be able to assess the pregnant mothers’ quality of life, especially those diagnosed with diabetes during the pregnancy.
The face, content, exploratory factor analysis, and reliability are required to assess psychometric properties of a questionnaire (19). In this study, qualitative and quantitative face validity, qualitative and quantitative content validity, exploratory factor analysis, convergence validity, and reliability were evaluated for GDMQ–36 questionnaire. For its face validity, after correcting the ambiguous items, the impact factor was calculated for each item, where items with impact factor of less than 1.5 were omitted. In content validity, CVR and CVI were calculated for each item, where items with CVR of less than 0.62 and CVI of less than 0.79 were removed, after consultation with the research team. The review of the items deleted in face and content validity evaluation phase indicated that their concepts were explained by the remaining variables. S-CVI was equal to 0.99 demonstrating that the entire tool has a desirable and robust strong validity (25).
Exploratory factor analysis was used for validity of GDMQ–36 questionnaire. Factor analysis is performed in two general forms called exploratory and confirmatory factor analysis. The confirmatory factor analysis is used to confirm previous work. In exploratory factor analysis, the researcher seeks to discover the underlying structure of a relatively large set of variables, with the initial assumption being that each variable may be related to each of the factors. In other words, the researcher has no initial theory in this method (25). In exploratory factor analysis of GDMQ–36, five factors explained 46.68% of the total variance of the questionnaire through exploratory factor analysis.
Diabetes clients’ quality of life (DCQOL) questionnaire was used for convergent validity of GDMQ–36 questionnaire. Since there was no quality of life questionnaire for women with GDM, diabetes’ quality of life questionnaire was used. Among the diabetes’ quality of life questionnaires, Diabetes clients’ quality of life (DCQOL) questionnaire proved to be more appropriate, since this questionnaire was developed and assessed regarding its psychometric properties in Iran (17) and has been closer to GDMQ–36 questionnaire in terms of culture. Statistical analysis showed a moderate and significant relationship between the two questionnaires which was acceptable (42). Factors of concerns about high-risk pregnancy, perceived constraints, as well as medication and treatment in GDMQ–36 questionnaire had a significant relationship with factors of disease and treatment in the DCQOL questionnaire. Comparison of the items of these factors revealed that the concept of some items of the disease and the treatment factor in the DCQOL questionnaire existed in the three domains of GDMQ–36 questionnaire. However, the items of DCQOL questionnaire captured more general concerns and did not take into account pregnancy concerns. The disease complications of GDMQ–36 questionnaire had a significant correlation with the psychological domain of the DCQOL questionnaire, while the physical complications of the DCQOL questionnaire included those more related to the physical problems of chronic diseases. The support factor of our questionnaire had a significant and inverse relationship with the social domain of the DCQOL questionnaire. Specifically, in our questionnaire, the items about support were positive while in the DCQOL questionnaire, the items associated with support were negative, and it was of the long-term social complications of the disease.
One strong point of this study was the use of exploratory mixed methods including qualitative and quantitative phases for development and assessment of psychometric properties of the questionnaire. The participants of this study were mothers suffering GDM with the highest diversity in age, education, economic status, gestational age, and type of treatment (diet or insulin, inpatient or outpatient treatment).This makes it easier to evaluate the quality of life of mothers with GDM through GDMQ–36 questionnaire. Nevertheless, this study had also some limitations. The most important was that the questionnaire was developed in Iran, thus requiring translation and revalidation in other communities. It seems that a well-designed questionnaire can be used in various communities after being fully translated and evaluated by the professionals in those communities (43).