Abstract
The study analyses factor structure and psychometric properties of the Italian version of the Fertility Problem Inventory–Short Form. A sample of 206 infertile couples completed the Italian version of Fertility Problem Inventory (46 items) with demographics, State Anxiety Scale of State-Trait Anxiety Inventory (Form Y), Edinburgh Depression Scale and Dyadic Adjustment Scale, used to assess convergent and discriminant validity. Confirmatory factor analysis was unsatisfactory (comparative fit index = 0.87; Tucker-Lewis Index = 0.83; root mean square error of approximation = 0.17), and Cronbach’s
Introduction
Infertility is clinically described as a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse (Zegers-Hochschild et al., 2009) affecting 9%–15% of couples worldwide (Boivin et al., 2007) and 10%–12% of couples in Italy (ISTAT, 2015). Several studies highlighted that infertility is a deeply distressing experience affecting quality of life (Aarts et al., 2012; Huppelschoten et al., 2013; Monga et al., 2004; Onat and Beji, 2012; Ozkan et al., 2015; Shindel et al., 2008), self-esteem (Daniluk and Hurtig-Mitchell, 2003) and quality of marital and sexual relationships (Nelson et al., 2008; Repokari et al., 2007; Wischmann and Thorn, 2013; Yazdani et al., 2016), and inducing mood disorders, anxiety and depression (Luk and Loke, 2015; Peterson et al., 2013; Williams et al., 2007; Wischmann et al., 2001).
Referring to Lazarus and Folkman’s (1984) transactional model of stress process, in the last decades, several studies developed different measures to explore stress dimensions in infertile patients (Abbey et al., 1991; Bernstein et al., 1985; Collins et al., 1992; Glover et al., 1999).
All measures described has been considered adequate in terms of patients’ burden, due to the number of items included; nevertheless, each of them focused only on some specific dimensions of infertility-related stress.
In this perspective, the
The original version of the FPI was obtained by following a sequential strategy of scale construction and selecting all items able to enhance convergent and discriminative validity. The final 46-item questionnaire consisted of five scales identified as
The FPI identifies and measures significant domains of infertility-related stress. Research revealed that personal and marital stress dimensions significantly associated with treatment outcomes (Boivin and Schmidt, 2005; Cooper et al., 2007); moreover, it emerged significant gender differences concerning the effects of self-related stress dimensions on perceived levels of anxiety and depression (Lykeridou et al., 2009; Peterson et al., 2007), marital satisfaction (Peterson et al., 2003) and resilience processes (Herrmann et al., 2011; Sexton et al., 2010).
Validation studies of FPI have been proposed in different countries such as Greece (Gourounti et al., 2011), China (Peng et al., 2011), Portugal (Moura-Ramos et al., 2012) and Korea (Kim and Shin, 2014), substantially confirming the original structure of the questionnaire.
In Italy, the first validation study (Donarelli et al., 2015) didn’t confirm the original multidimensional structure of the test, and post hoc explorative factor analysis, conducted to determine the model of best fit, extracted two factors explaining 25% of variance. The first factor contained 29 items merging all the items from
In this perspective, this study moved both from the interest in the multidimensional structure of the FPI and from the consideration of the great burden of the 46-item original questionnaire. Therefore, it aimed to re-examine psychometric properties and factorial structure of the Italian version of the test in order to develop a valid and reliable Fertility Problem Inventory–Short Form (FPI-SF).
Methods
Study design and participants
The study protocol was approved by the Ethical Committee of the University were this study took place, and research was performed in accordance with the Declaration of Helsinki.
A cross-sectional study was conducted with the aim to re-examine psychometric properties and factor structure of the Italian version of FPI and to validate a short-form, comparing infertility-related stress dimensions emerged with respect to both individual characteristics of patients (gender, age and educational level) and infertility-related characteristics (type of diagnosis, presence of previous treatments and infertility treatment period).
The study was conducted between April 2015 and September 2016. Chairman of different Italian Centres of Assisted Reproduction of Naples (six centres), Udine (one centre) and Brescia (two centres) were contacted to enlist their participation to the project and gave the authorization for submitting a questionnaire to the infertile couples undergoing treatments in their centres. Inclusion criteria were as follows: (a) couples who had been diagnosed with infertility (Male Factor; Female Factor; Combined Male and Female Factor; and Unexplained); (b) couples who were undergoing an infertility treatment of intrauterine insemination (IUI) or in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI); c) the agreement by both members of the couple to participate in the study in order to consider couple sharing infertility problems as research unit. About 500 subjects (both partners of 250 couples) were asked by their physician to participate in the study before their appointment. If one or both partners refused to complete the survey, they were not included in the final data set; therefore, 12 couples with males not responding and 32 couples with no response from either partners were excluded. Overall, 206 couples (206 male, 206 female) completed the questionnaire (response rate = 82.4%).
The questionnaire lasting 20–25 minutes (one session) was submitted individually to both members of the infertile couples in a quiet room setting in the medical centre, and one of the authors was always present to answer any queries raised by participants. The respondents were informed of the objectives of the study, and informed consent was obtained from all participants. The couples voluntarily and anonymously participated in the survey, and received no compensation for their collaboration.
Measures
A questionnaire composed of five sections was submitted. Section 1 included items pertaining to socio-demographics (age, sex, educational level) and data on type of diagnosis (Male Factor; Female Factor; Combined Male and Female Factor; and Unexplained), presence of previous treatments (No/Yes) and infertility treatment period (≤ 1 year/>1 year). Data provided by the participants were double checked with those reported by the physicians. Section 2 consisted of the Italian version of the FPI (Donarelli et al., 2015), a self-administrated measure composed of 46 items on a 6-point Likert scale ranging from one (
Statistical analysis
Descriptive statistics, factor analysis, Pearson’s correlations and analyses of variance (ANOVAs) were tested using SPSS version 21.
On the basis of data emerged, an exploratory factor analysis (EFA) using principal axis factoring analysis with oblique promax rotation was performed to improve the fit of the model with our data. The choice of non-orthogonal rotation was justified on the hypothesis that the factors would be correlated. The factorability of the correlation matrix of the FPI was evaluated by Kaiser–Meyer–Olkin (KMO) measure and Barlett test of sphericity. Criteria for extraction and interpretation of factors were as follows: eigenvalues >1.0, Cattell’s scree test and inspection of scree plot, communality ≥0.30 for each item and factor loading >0.32 for each item loading on each factor (Costello and Osborne, 2005). CFA was performed to assess the robustness of the structure of the FPI-SF derived from the EFA. Moreover, Mokken scale analysis was carried out using the R package ‘Mokken’ to further validate the emerged version of FPI-SF verifying the items homogeneity within the reduced subscales of the questionnaire. The scale’s and items’ Loevinger’s scalability coefficients (
Finally, Convergent validity was assessed by analysing the correlations of FPI-SF subscales and Global Stress scores with the standardized scales scores of STAI-Y, EDS, and DAS. Discriminant validity was evaluated by exploring the intercorrelations between the subscales, and ANOVA tests were used to analyse differences in FPI-SF subscales and Global Stress mean scores between subgroups of infertile patients divided by sex, age (the mean age of 34 years was used as a cut-off point), educational level (Junior Middle School; Senior School; College), type of diagnosis (Male Factor; Female Factor; Combined Factor; Unexplained Factor), previous treatments (No/Yes) and infertility treatment period (1 year has been considered as a cut-off point in accordance with the literature; Kim and Shin, 2014).
Results
Characteristics of participants
The study was carried out in a sample of 206 Italian infertile couples. The ages of participants ranged from 22 to 48 years (
Demographic and infertility-related characteristics of participants (
IVF: in vitro fertilization; ICSI: intracytoplasmic sperm injection; IUI: intrauterine insemination.
Item analysis of the original version of FPI
Preliminarily, the symmetrical distribution of item scores (skewness and kurtosis values) and the internal consistency (Cronbach’s
The FPI revealed a very high Cronbach’s
CFA
The theoretical model of the FPI (Newton et al., 1999) was tested by CFA, which indicated a low fit between data collected and the theoretical model: χ2 value statistical significant (
EFA
The EFA was conducted using principal axis factoring analysis with oblique promax rotation. The assessment of factorability showed that the Kaiser–Meyer–Olkin measure was 0.83 and Barlett’s test of sphericity was significant (
Factor structure of the 27-item Fertility Problem Inventory–Short Form (FPI-SF).
Only items with factor loading ≥0.32 are shown. Total variance explained = 44%. Cronbach’s
Table 3 illustrates items, means, SD and ranges of the FPI Short-Form subscales and the total scale (
Items, mean, SD and range scores of Fertility Problem Inventory–Short Form scales.
FPI-SF: Fertility Problem Inventory–Short Form.
Item analysis of the FPI-SF
Following the analysis of the factor structure of the FPI, the emerged new short version of the questionnaire has been submitted to item analysis. Mean scores for the single items varied from a maximum score of 4.78 (Item 5: ‘Being a parent is a more important goal than having a satisfying career’) to a minimum of 1.81 (Item 22: ‘Having sex is difficult because I don’t want another disappointment’). SDs for the single items varied from 2.02 (Item 44: ‘It doesn’t bother me when others talk about their children’) to 1.26 (Item 22: ‘Having sex is difficult because I don’t want another disappointment’). The skewness and kurtosis varied from −1.5 to 1.5, indicating a normal distribution of the scores. Item total correlation was significant for all items (0.20 <
Convergent and discriminant validity
Correlations with measures of State Anxiety (STAI-Y), Depression (EDS) and Dyadic Adjustment (DAS Tot) were carried out to test convergent validity, showing that all FPI-SF subscales and
Correlations of Fertility Problem Inventory–Short Form scales with State Anxiety, Depression and Dyadic Adjustment scales.
Concerning discriminant validity, intercorrelations between the scales of FPI-SF and correlations between the four subscales and the
Intercorrelations between Fertility Problem Inventory–Short form (FPI-SF) scales.
Moreover, ANOVA tests (Table 6) showed, concerning demographic characteristics, that female infertile patients perceived significantly higher levels of
Differences in the Fertility Problem Inventory–Short Form scales scores by gender, age, educational level, type of diagnosis, presence of previous treatments, infertility treatment period.
Discussion
Findings highlighted that the proposed Italian FPI-SF possessed adequate factor validity and reliability, tapping four meaningful and reliable factors which allowed to substantially confirm the original multidimensional structure of the FPI (Gourounti et al., 2011; Kim and Shin, 2014; Moura-Ramos et al., 2012; Newton et al., 1999; Peng et al., 2011). Three dimensions of the original version, that is,
The final 27-item version of FPI-SF showed a satisfactory fit of the data structure with the theoretical model of the test and an excellent internal consistency, offering the further relevant advantages of being a synthetic and abbreviated valid version of FPI for use in clinical practice and research. In this perspective, the analysis of convergent validity of FPI-SF revealed significant associations of all its subscales scores with perceived levels of State Anxiety, Depression, and Dyadic Adjustment in the expected directions, and the discriminant validity analyses confirmed that all scales assessed different but connected dimensions of infertility-related stress. Finally, the FPI-SF allowed the assessment of all infertility-related stress dimensions of the construct differentiated by individual characteristics of gender, age, educational level, and by infertility-related characteristics of type of diagnosis and duration of infertility.
In particular, data provided important information from a clinical point of view, highlighting several differences in stress dimensions by gender and type of diagnosis, the protective role of educational level and the duration of infertility treatment period as significant risk factor. In this perspective, the FPI-SF could be usefully applied to assess risk and protective factors and to define more focused interventions.
Despite these merits, some limitations need to be underlined. First, the test–retest reliability of the FPI-SF was not covered in this study, so that actually it is not possible to evaluate the temporal stability of our measures. Second, the study revealed some significant effects of individual characteristics and infertility-related characteristics that should be object of further analysis and investigations. Moreover, further studies should be developed to better explore the effects of responsiveness to treatments (i.e. success or failure of treatments) on infertile patients’ perceived levels of stress. Finally, considering that cultural and social variables may influence quality and intensity of infertility-related stress dimensions, future studies should be conducted using the FPI-SF with different infertile populations.
Despite these limitations, the FPI-SF constitutes a synthetic, reliable and valid multidimensional measure to assess stress dimensions among infertile patients in clinical practice and research, to define evidence-based interventions aiming to reduce infertility-related stress, non-compliance and discontinuation in Assisted Reproduction Treatment, and to promote individual and couples’ psychological health in infertile patients.
Footnotes
Acknowledgements
The authors wish to thank all the study participants for completing the questionnaire.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship and/or publication of this article.
