The Brazilian version of the Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy: translation, cross-cultural adaptation and reliability – an observational cross-sectional study

ABSTRACT BACKGROUND: The Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy (NVPQOL) is a validated questionnaire assessing quality of life among pregnant women with nausea and vomiting. OBJECTIVE: To translate, cross-culturally adapt and evaluate the reliability of the NVPQOL. DESIGN AND SETTING: Observational cross-sectional study developed in a public university in Brazil. METHODS: The translation, synthesis of translations, back-translation, expert committee, pre-testing and validation were carried out, resulting in a Portuguese-language version. The internal consistency, intra-rater and test-retest reliability and correlation between the total score of the Portuguese-language version of the NVPQOL and the domains of the World Health Organization Quality of Life-bref questionnaire were considered in the data analysis. RESULTS: The instrument went through the process with testing on 104 pregnant women. Strong internal consistency (Cronbach's α: 0.95), strong intra-rater and test-retest reliability (P < 0.0; intraclass correlation coefficient: 0.89; confidence interval: 0.791-0.945) and strong correlation between the total score of the Portuguese-language version of the NVPQOL and the physical health domain of the World Health Organization Quality of Life-bref questionnaire (P < 0.01; R = −0.8) were observed. CONCLUSION: The NVPQOL was translated, cross-culturally adapted and validated for the Portuguese language with satisfactory psychometric properties for assessing quality of life, especially in relation to physical health, among pregnant women with symptoms of nausea and vomiting in the first trimester of pregnancy.


INTRODUCTION
Nausea is defined as an uncomfortable sensation that is associated with the urge to vomit, while vomiting is characterized by oral expulsion of gastric contents. 1 These symptoms are common during the first gestational trimester, affecting 70-80% of pregnant women, and their cause is still uncertain. 2,3 They are responsible for physical and emotional impairment, which tends to trigger social isolation and compromise quality of life, given that, according to Hizli et al., 4

to 12%
of pregnant women with these symptoms isolate themselves socially. Pregnant women's common complaints include uncomfortable symptoms of physical discomfort that prevent them from successfully performing their daily activities. These involve negative feelings about pregnancy, which can give rise to emotional conflicts in these women's relationships with the baby and family.
These symptoms are more prevalent among young, multiparous and multiple gestation pregnant women. 5 They tend to soften after the 22 nd gestational week, 6 although in some women they may continue until the end of the gestation, 6 thus characterizing pregnancy hyperemesis. In such cases, the symptoms of nausea and vomiting of pregnancy are persistent, excessively compromising and untreatable. They may lead to dehydration, ketosis, weight loss and electrolyte and nutritional disorders. 4,7,8 Investigating the frequency of these symptoms and their impact on women's quality of life can help professionals to understand this condition, in order to minimize the impact of nausea and vomiting on this very special phase of women's lives. For this purpose, Lacasse et al. 9

Study type
This was an observational cross-sectional study.

Description of the Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy
The Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy is a self-administered questionnaire that was developed by Magee et al. 10 10 For each question in the questionnaire, a range of possible responses is provided using a seven-point Likert scale, on which 1 represents "none of the time" and 7 represents "all of the time". The sum of the scores from these questions results in a total score ranging from 30 to 210. The lower the score is, the higher the quality of life is. 9

Ethical issues
In order to begin the study, authorization was sought from the author Dr. Laura Magee, which was granted. Furthermore, approval was given by the Institutional Review Board of the study university, in accordance with the ethical and legal precepts (Institutional questions and responses to the questionnaire were generated.

Stage II: Synthesis
The two versions generated in stage I (T1 and T2) were synthesized into a common version (T12) and all divergences were reported and agreed by the researchers responsible for this study.

Stage III: Back translation
The synthesized version (T12) was back-translated by two independent translators, who were native speakers of the English language and not healthcare professionals. Thus, two back-translated versions (BT1 and BT2) were generated. These presented content that was similar to that of the original version, thus ensuring consistency of the translation.

Evaluation of the reliability of the Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy_Portuguese
After the translation, cross-cultural adaptation and content validation processes had ended, the reliability of the instrument was ascertained among another 36 pregnant women. These subjects were recruited from among the attendees at doctors' offices and the family health program of the municipality of Alfenas (MG), Brazil. These women attended two face-to-face interviews conducted by the same researcher, who had been trained and qualified to maintain an interview standard. There was a seven-day interval between the interviews. 13 At both interviews, the subjects gave responses to two instru- The inclusion criteria were that the participants needed to be over 18 years of age, with a pregnancy of gestational age less than 16 weeks. Women presenting neurological abnormalities, disorders and/or cognitive limitations that precluded participation in the study were excluded. Women who did not participate fully in the proposed activities, i.e. attendance at both interviews, were considered to have discontinued their participation.

Data analysis
The data analysis was carried out by two researchers and the following tests were performed: Cronbach's alpha coefficient test for internal consistency analysis (considering the first interview); 16  were used for data analysis. Coefficients below 0.5 were considered to present "poor reliability"; coefficients between 0.5 and 0.75, "moderate reliability"; and coefficients above 0.75, "strong reliability". 16 In all the analyses, a 95% confidence interval (CI) was used.
No inter-rater analysis was performed, given the self-applicable nature of the instrument, which does not require any intervention from the evaluator.
The Survio platform was used to make the questionnaires available and to collect answers in the different stages of the translation and expert committee analyses.

RESULTS
The whole process involved 140 pregnant women, who participated either in the pretesting process (n = 104) or in the reliability process (n = 36). Table 1 presents the study population for the process of cross-cultural adaptation and evaluation of the reliability of the Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy_Portuguese. Table 2 presents the adaptations made during the process of translation and cross-cultural adaptation, through conformity analysis between the original and translated versions of the instrument.

Internal consistency
The Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy_Portuguese showed strong internal consistency (Cronbach's α coefficient = 0.95).

Main findings
The The validation study among women in the first trimester of pregnancy was conducted by Lacasse et al. 9 in 2008, using a sample of 288 pregnant women with symptoms of nausea and vomiting of pregnancy. Our study was designed in accordance with the same criteria used by Lacasse et al., 9 in spite of adding the test-retest and intra-rater reliability analyses.
Our study found excellent internal reliability for the complete questionnaire, thus corroborating the results from the study by Lacasse et al. 9 In theory, reliability analyses follow the condition that the higher the test-retest reliability is, the higher the internal reliability also is, which was observed in the present study. 18

Clinical and research implications
Health status is a factor relating to quality of life that is one of the essential components of health-related quality of life. 19 During the gestational period, there are important physiological changes and consequent emotional and physical changes that impact on women's health and quality of life, and these may negatively affect the mother-child binomial.
It is known that symptoms of nausea and vomiting of pregnancy affect up to 80% of women. They have greatest occurrence in the first trimester 20 and tend to decrease after this period. This justifies investigation of such symptoms during this period, through clinical research on the impact of nausea and vomiting of pregnancy on the quality of life of pregnant women.
Our study involved 140 women during the process of cross-cultural adaptation and validation, and we found that the questionnaire presented strong statistical validity, thus demonstrating its psychometric properties with regard to women in their first trimester of pregnancy.

According to the American College of Obstetricians and
Gynecologists, 21 most cases of nausea and vomiting of pregnancy are self-limiting with a peak incidence around the 9 th gestational week and symptom relief around the 20 th gestational week. The present study was conducted with a limit on assessment and reassessment (test-retest) that was set at the 16 th week of gestation, as was done in the validation study conducted by Lacasse et al., 9 although the original study included women up to the 20 th week. 10 This approach was justified not only by the fact that the prevalence is highest in the first trimester, but also because complaints that tend to persist throughout the gestational process are already characterized as hyperemesis gravidarum and may involve other related factors, despite lack of full knowledge of the etiology so far. 22 In addition, the effect of memory and other characteristic symptoms of each gestational phase could influence the perception of health and consequently the quality of life in other gestational periods, such as the sensation of heartburn, which is a common characteristic of the last gestational trimester. 23 Additionally, the emotional conflict experienced by these women, involving the mother-child relationship, needs to be considered, given that the impact of any distress after the acute phase of nausea and vomiting tends to be minimized. In this regard, reliability studies have affirmed that the time interval between measurements may influence the interpretation of the test-retest reliability. 17 Therefore, we took care not only to always reapply the instrument after a seven-day interval, but also to ensure that the whole process was completed before reaching 16 weeks of gestation.
Improving the measurement quality of factors relating to the quality of life of pregnant women with symptoms of nausea and vomiting was one of the main contributions of the present study to clinical practice.

Quality of life implications
A strong correlation was found between the total score of the However, there are inconsistencies between different studies that may reflect differences between populations. In interpreting the results from these studies in relation to quality of life, it is necessary to consider their environmental and cultural aspects. 28 In this regard, the present study showed a weak correlation with the This finding also demonstrates the importance of thoroughness in interpreting the validation process of this study. We found greater correlations between certain domains of these two instruments, which have different scoring systems and ways of calculating them.

Strengths, limitations and suggestions for further studies
We suggest that future research should include use of the Health-  We also suggest that antiemetic treatment should be individualized and the effect of each intervention should be measured in terms of the patient's own reported outcome. This corroborates the idea that validated instruments should be indicated for investigating the presence, severity and impact of pregnancy nausea and vomiting on the quality of life among patients, who will evaluate for themselves the reported efficacy and effects, and their preferences.
It is also important to consider that the impact of nausea and vomiting of pregnancy on quality of life may differ from individual to individual. Some individuals may even suffer continuously, with daily complaints that are secondary to nausea-triggering processes such as first-trimester gestation, a chemotherapy treatment period or a postoperative period. Others may suffer from sporadic nausea, such as symptoms that affect individuals during a trip, for example.
In a study by Dean et al., 30 lack of attention towards addressing the symptoms of nausea and vomiting of pregnancy by healthcare professionals was reported. Thus, it is essential to emphasize the importance of using a validated assessment instrument that is available to Brazilian professionals and their patients.