PLOS ONE RESEARCH ARTICLE Reliability and validity study of the Spanish adaptation of the “Wijma Delivery Expectancy/ Experience Questionnaire” (W-DEQ-A) Celia Maria Ortega-Cejas1, Juan Roldán-Merino ID2,3,4*, Teresa Lluch-Canut4,5, Mª Isabel Castrillo-Pérez6, Mª Mercedes Vicente-Hernández7, Marta Jimenez-Barragan8, Ainoa Biurrun-Garrido2,3, Mariona Farres-Tarafa2,3,9,10, Irma Casas11,12,13, Sandra Cabrera- Jaime5,14,15 1 Midwife, Sexual and Reproductive Health Clinic (ASSIR), Mollet del Vallès, Barcelona, Spain, 2 Campus Docent, Sant Joan de Déu - Fundació Privada, School of Nursing, University of Barcelona, Barcelona, Spain, a1111111111 3 Research Group GIES (Grupo de investigación en Enfermerı́a, Educación y Sociedad), Barcelona, Spain, a1111111111 4 Research Group GEIMAC (Consolidated Group 2017-1681: Group of Studies of Invarianza of the a1111111111 Instruments of Measurement and Analysis of Change in the Social and Health Areas), Barcelona, Spain, 5 Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain, 6 Midwife, Sexual a1111111111 and Reproductive Health Clinic (ASSIR) La Riera, Badalona, Barcelona, Spain, 7 Midwife, Sexual and a1111111111 Reproductive Health Clinic (ASSIR) Doctor Barraquer, Sant Adrià del Besòs, Barcelona, Spain, 8 Midwifery Coordinator, Sexual and Reproductive Health Clinic (ASSIR) Fundació Assistencial Mútua Terrassa, (Terrassa) Midwife, Sexual and Reproductive Health Clinic (ASSIR) Rambla Terrassa, (Terrassa) Docente en Fundació Universitaria del Bages, Barcelona, Spain, 9 Member Research Group GRISIMula (Grupo emergente 2017 SGR 531; Grupo en Recerca Enfermera en Simulación), Barcelona, Spain, 10 Secretary, GRISCA Research Group (Nurising Simulation in Catalonia and Andorra Research Group), Barcelona, Spain, OPEN ACCESS 11 Universitat Autònoma de Barcelona, Barcelona, Spain, 12 Preventive Medicine Service, Hospital Citation: Ortega-Cejas CM, Roldán-Merino J, Germans Trias i Pujol, Barcelona, Spain, 13 Research Group Innovation in Respiratory Infections and Lluch-Canut T, Castrillo-Pérez MI, Vicente- Tuberculosis Diagnosis (Group Consolidat 2017 SGR 494), Barcelona, Spain, 14 Corporate Care Hernández MM, Jimenez-Barragan M, et al. (2021) Management, Institut Català d’Oncologia (ICO), L’Hospitalet de LLobregat, Barcelona, Spain, 15 GRIN Group, IDIBELL, Institute of Biomedical Research, Barcelona, Spain Reliability and validity study of the Spanish adaptation of the “Wijma Delivery Expectancy/ * juan.roldan@sjd.edu.es Experience Questionnaire” (W-DEQ-A). PLoS ONE 16(3): e0248595. https://doi.org/10.1371/journal. pone.0248595 Editor: César Leal-Costa, Murcia University, SPAIN Abstract Received: January 19, 2021 The Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ-A) is an instrument Accepted: March 1, 2021 that evaluates fear of childbirth through the expectations of women in relation to childbirth and their experience during the birth. The objective of this study was to translate the W- Published: March 19, 2021 DEQ-A into Spanish and analyse its reliability and validity. The study was carried out in two Copyright: © 2021 Ortega-Cejas et al. This is an phases: (1) adapting the questionnaire to Spanish and (2) a transversal study in a sample of open access article distributed under the terms of the Creative Commons Attribution License, which 273 pregnant women in the Sexual and Reproductive Health centres in the Metropolitan permits unrestricted use, distribution, and Northern Barcelona in Catalonia (Spain). The psychometric properties were analysed in reproduction in any medium, provided the original terms of reliability and construct validity. The confirmatory factorial analysis did not confirm author and source are credited. the unidimensionality of the original structure of the WDEQ-A, as happened with the other Data Availability Statement: All relevant data are studies in which it has previously been validated. The result of the exploratory factorial anal- within the paper and its Supporting information ysis suggests four factors, or dimensions, very similar but not identical to those obtained in files. other analysis studies of the W-DEQ-A. The Cronbach alpha and the omega scale were Funding: This study has been funded by the also adequate for all the scales and for each of the dimensions. The results of this study con- Germans Trias i Pujol Research Institute with the Retainment of Talent grant in 2014. firm the findings of other studies that suggest that the W-DEQ-A is multi-dimensional. In the Spanish version of the W-DEQ-A four dimensions have been identified to explore fear of Competing interests: The authors have declared that no competing interests exist. childbirth in pregnant women. The Spanish version of the WDEQ-A (WDEQ-A-Sp) is reliable PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 1 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp and valid for the measurement of fear of childbirth in clinical practice and for use in future research. Introduction Pregnancy and future childbirth is one of the most important life events in the life of a woman and the experience of birth can be defined as a complex individual life process that incorpo- rates psychological and profound subjective physiological processes [1]. Most women experi- ence feelings of anxiety or worry about the development and wellbeing of the pregnancy, the baby and about the birth throughout the pregnancy [2]. However, this worry focussed on the birth can set off feelings of anxiety or intense fear [3, 4]. In some pregnant women this emotion can lead them to have feelings of avoidance of the birth that coincide with the definition of phobia according to the diagnostic criteria of the DSM-V [5–7]. The term tokophobia is used to refer to pathological fear of childbirth [8] and is defined as that which affects or interferes with the everyday life of pregnant women [9, 10]. Tokophobia is classified as primary if it affects nulliparous women, or secondary if it affects multiparous pregnant women [5]. How- ever, consensus does not exist on the definition of fear of childbirth [11], or on the measuring tool to detect it [12], so in the literature it is described as light, moderate or severe [13]. The prevalence of fear of childbirth has been difficult to ascertain due to the wide variability of results in different studies carried out in different countries and populations, as well as a consequence of varying definitions referenced on fear, describing rates varying from 3.7% to 43% for prevalence [14]. For this reason, a systematic review carried out by O’Connell esti- mated global fear of childbirth at 14% [14]. Prevalence of fear of childbirth is also different in function of the births a woman has experienced and greater in nulliparous women than in multiparous women [15]. While stress, anxiety, depression and a lack of social support have been related to high levels of fear in nulliparous women, having a negative experience at a previous birth is what causes the greatest fear of childbirth amongst multiparous pregnant women [16], as is the case of those who have been subjected to a previous caesarean or vacuum-assisted births [17]. Equally, other factors have been associated with a greater level of fear of childbirth such as: a history of mental illness [18], history of sexual abuse [19] and low self-esteem [20]. Similarly, several studies have analysed the elements that make up fear of childbirth. Women refer to their worries being related to fear of the unknown, the possibility that they or the baby suffer injuries, fear of pain, fear of loss of control, doubts about their ability to give birth or a lack of support from health providers [21, 22]. Fear of childbirth has been associated with a higher risk of elective caesarean [17, 23–25], higher risk of emergency caesarean [26, 27] and increased risk of suffering post-traumatic stress during the post-natal period [28, 29]. It has also been associated with greater use of epi- dural anaesthetic [30, 31], prolonged labour [32] and greater probability of dystocia during pushing [26]. During recent years various instruments have been developed to screen for fear of child- birth. Nevertheless, the questionnaire most used for fear of childbirth is the Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ) and it is the only one that evaluates antepar- tum and postpartum fear [12]. The W-DEQ questionnaire was published by Wijma et al. in 1998. It is a self-administrated questionnaire; it has 2 versions with 33 items each, which evaluate fear of childbirth through PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 2 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp the expectations of women in relation to the birth (WDEQ A) and the experience of stress after the birth (WDEQ B). Since the questionnaire was developed it has been translated into several languages and has been used in different studies to explore fear of childbirth [23, 33–47]. However, although it was conceived as a unidimensional instrument, different analyses carried out in the different validations have shown a multifactorial structure [13, 33, 34, 37, 39, 41–47]. Table 1 shows the languages and populations where it has been validated and the principal characteristics of each validation. Although fear of childbirth is a socially recognized phenomenon in Spain, it is not clinically studied during the development of the pregnancy because there is no validated questionnaire available in Spanish [50]. Given the prevalence indicated in other countries and the perinatal repercussions it brings; a validated tool to carry out screening for fear of childbirth for preg- nant women in Spain is needed. This would allow midwives to detect it and carry out interven- tions to reduce the repercussions for the benefit of the health of the pregnant woman and the newborn. To achieve this, the objective of this study was to translate into Spanish and analyse the reli- ability and validity of the Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ-A). Methods Design The study was carried out in two phases. In the first phase, the W-DEQ-A questionnaire was adapted to Spanish: in the second phase the metrics of the version translated to Spanish were analysed. Participants and setting The sample for the study was made up of 273 pregnant women in the Sexual and Reproductive Health Clinics in the Northern Metropolitan region in Barcelona in Catalonia (Spain). The questionnaires were administered to pregnant women during routine prenatal visits in the 34 weeks of gestation. To complete the questionnaires, pregnant women were asked to answer how they thought they would feel during labour and how they imagined labour would be. Pregnant women over 18 years of age and who did not present language difficulties in reading and completing the questionnaire in Spanish were selected. Women with a history of perinatal death were excluded. The women were recruited consecutively during the study period between January 2019 and January 2020. The size of the sample was calculated from the recommendations of various authors who recommended between 5 and 20 participants for each item featuring on the questionnaire [51, 52]. In this study it was agreed to include 10 participants for each item featuring on the ques- tionnaire. As a consequence of the COVID-19 pandemic, the study finished in January 2020 as it was considered that fear of COVID-19 at the time surrounding childbirth among the preg- nant women from this date onwards could be a factor that influenced the results. Finally, 8 pregnant women were included for each item on the questionnaire. The sample of 273 partici- pants was deemed adequate to carry out the study. Variables and source of information All the items on the W-DEQ-A questionnaire were included as variables. It is a questionnaire made up of 33 items, which in the original version are grouped in one single dimension. PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 3 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 1. Summary of the characteristics of the WDEQ validated in the different languages and countries. Author Language; Sample Type of Number of Factors labels Item Reliability Country (year) analysis factors (items) Johnson & Slade [34] English; UK 443 EFA 4 (31) Fear 6,19,17,12,5,2,16,8,22,24,20,25,4,27,10 .91 (2002) Isolation 15,7,3,11 Lack of positive 14,18,13,21,1,29,30,23 anticipation Riskiness 33,32,31,9 Wiklund et al. [37] Swedish; Sweden 496 EFA 4 (33) Fear 6,4,5,17,29,22,30,8,12,9,26,10,19,16,2,7,31 No data Lack of positive 18,14,13,21,1,28,23,15,3 anticipation Isolation 25,24,27,20,11 Riskiness 32,33 Fenwick et al. [13] English; Australia 401 EFA 4 (32) Fear 17,19,12,2,6,16,5,4,24,25,10,28 .91 (2009) Isolation 14,13,18,30,22,21,29,23,1,9 Lack of positive 15,7,11,3,20,8,31,27 anticipation Riskiness 32,33 Garthus-Niegel et al. [39] Norway (2011) 1680 CFA 6 (25) Fear 6,12,19,20,24,27 .75-.87 Negative appraisal 1,13,14,18 Loneliness 3,7,15 Lack of self-efficacy 4,5,9,10,16,22,26 Lack of positive 28,29,30 anticipation Concerns for the 32,33 child Takegata et al., [41] Japanese (2013) 231 EFA 4 (33) Fear 19,25,16,27,12,17,22,2,6,4,5,24,10, .70 28,26,23,29,30 Isolation 7,11,3,15,8,20 Lack of positive 18,13,14,9,21,1 anticipation Riskiness 32,33,31 Fenaroli et al., [33] Italian (2013) EFA 4 (16) Fear 6,19,2,24,12,25,27,8 No data Negative feelings 13,18,14 Lack of confidence 22,23,9 Negative thoughts 32,33 Fenaroli et al., [33] Italian (2013) 500 CFA 3 (14) Fear, 6,19,2,24,25,27,8,12 .86 Negative feelings 13,18,14 Lack of confidence 22,23,9 Lukasse et al. [47] Norwegian 6870 EFA 6 (33) Lack of self-efficacy 5,22,10,17,4,16,9,23,12,26 .92 Swedish Danish Estonian Loneliness 7,11,15,20,8,3,6 Flemish Negative appraisal 14,18,13,21,1 Icelandic Russian (2014) Lack of positive 29,30,28,31 anticipation Fear 25,27,24,19,2 Concerns for the 32,33 child (Continued ) PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 4 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 1. (Continued) Author Language; Sample Type of Number of Factors labels Item Reliability Country (year) analysis factors (items) Pallant et al. [48] Australia (2016) 1410 CFA 4 (17) Negative emotions 2,6,8,12,19 .82-.87 EFA Rash Lack of positive 5,9,17,18,23 Analysis emotions Social Isolation 3,7,11,15 Moment of birth 28,29,30 Mortazavi, F. [42] Farsi; Iran (2017) 405 EFA 6 (32) Lack of self-efficacy 13,10,9,5,14,17,18,23,22,4 .91 Lack of positive 28,21,29,30 anticipation Loneliness 15,11,8,7,3,2,20,31 Fear 19,6,24,16,12 Concerns for the 32,33 child Concerns about 27,25,26 losing control Abedi et al. [46] Persian; Iran 200 EFA 9 (33) Despair 3,7,8,11,12,15,20 .64 (2017) Confidence 4,5,9,13,16,22 Fear 2,6,19,24 Happiness 14,18,21,23,28 Loss of control 25,27,31 Independence 1,10,17 Concern about new- 32,33 born Obvious 29,30 Control 26 MoghaddamHossein Hungarian; 343 EFA 4 (30) Isolation 11,15,3,20,31,27,25,8,19,2 .92 et al. [45] Hungary (2018) Lack of positive 17,5,13,22,16,4,10,9,1,23,14 emotions Moment of birth 28,24,30,21,18 Fear 6,12,7,24 Andaroon et al. [43] Persian; Iran 220 EFA 6 (31) Lack of self-efficacy 4,5,10,13,14,16,17,20,22,23 .84 (2020) Fear 3,6,7,8,11,12,15 Negative appraisal 18,21,26,28 Lack of positive 2,19,25,27 anticipation Concerns about 30,32,33 child Loneliness 1,9,29 Khwepeya et al. [44] Malawi (2020) 264 EFA 3 (26) Not reported Not reported No data Malawi (2020) 264 CFA 3 (23) Fear 7,15,12,11,6,3,8,2,20,25 .84 Negative appraisal 14,17,31,1,18,13,9,16 Lack of self-efficacy 21,22,26,23,4,28,5,10 (Continued ) PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 5 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 1. (Continued) Author Language; Sample Type of Number of Factors labels Item Reliability Country (year) analysis factors (items) Pitel et al. [49] Slovak; Slovakia 279 EFA 7 (33) Lack of composure 16,17,12,26,10,24,25 .93 (2020) Negative appraisal 13,18,14,21,23,9 Lack of self-efficacy 5,4,22,27,21,8 Lack of positive 30,29,28 anticipation Fear and 20,19,31,11,6 hopelessness Loneliness 3,7,15 Concern for the 32,33 child https://doi.org/10.1371/journal.pone.0248595.t001 Each item is evaluated using an ordinal scale of 0 to 5. The extremes of the replies (0 and 5 respectively) correspond to the opposites of a feeling or thought. The minimal score is 0 and the maximum is 165. Scores over 85 indicate severe fear of childbirth and scores over 100 indi- cate clinical signs of fear of childbirth. In the original Wijma study [53] a Cronbach alpha of 0.87 was obtained. Other variables were also collected such as: age, level of education, employment status, number of births and presence or not of a partner. Procedure The cultural adaptation process of version A of questionnaire W-DEQ was carried out accord- ing to the Standards for Educational and Psychological Testing [54]. Prior to starting the trans- lation the author of the questionnaire’s permission was sought for its adaption for the Spanish population. The English version of the questionnaire provided by the author was translated to Spanish by independent Spanish sworn translators, whose mother-tongue was Spanish and who were fully competent in English, providing two versions of the questionnaire in Spanish W-DEQ-A, which were evaluated by a committee of experts made up of a gynaecologist, a psychologist specialised in the area of sexual and reproductive health, 3 midwives and a specialist research nurse. This version was sent to two new sworn translators unfamiliar with the original version whose mother tongue was English and fully competent in Spanish for the retro-translation to English. The two versions obtained were compared with the original questionnaire by the same committee of experts, who found no discrepancies that required modifications. Table 2 shows the semantic equivalence of items from English to Spanish. Pretest A pretest was carried out with a total of 30 pregnant women with the aim of evaluating the clarity and understanding of the items and the format and time for completion. The pregnant women concluded that it was easy to understand and required little time, between 10 and 15 minutes to complete it. After the debriefing it was not necessary to make any changes in either the format or the content. The Spanish version was named W-DEQ-A-Sp. PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 6 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 2. Shows the semantic equivalence of items from English to Spanish that were metrically validated on the W-DEQ-A-Sp. Item English Spanish Item 1 Fantastic Fantástico Item 2 Frightful Horrible Item 3 Lonely Sola Item 4 Strong Fuerte Item 5 Confident Confiada Item 6 Afraid Asustada Item 7 Deserted Desatendida Item 8 Weak Débil Item 9 Safe Segura Item 10 Independent Independiente Item 11 Desolate Desolada Item 12 Tense Tensa Item 13 Glad Contenta Item 14 Proud Orgullosa Item 15 Abandoned Abandonada Item 16 Composed Íntegra Item 17 Relaxed Relajada Item 18 Happy Feliz Item 19 Panic Pánico Item 20 Hopelessness Desesperanza Item 21 Longing for the child Deseosa del bebé Item 22 Self-confidence Autoconfianza Item 23 Trust Confianza Item 24 Pain Dolor Item 25 I will behave extremely badly Me comportaré estremadamente mal Item 26 I allow my body to take total control Permitiré a mi cuerpo tomar el control total Item 27 I will totally lose control of myself Voy a perder el control total de mi misma Item 28 Enjoyable Agradable Item 29 Natural Natural Item 30 Should be Como debe ser Item 31 Dangerous Peligroso Item 32 Fantasies that your child die during labour/delivery Fantası́as sobre si el bebé se muere durante el parto Item 33 Fantasies that your child will be injured during labour/delivery Fantası́as de que su bebé sufrirá lesiones durante el parto https://doi.org/10.1371/journal.pone.0248595.t002 Statistical analysis First a confirmatory factorial analysis (CFA) was carried out to test the unidimensional model of the original scale proposed by Wijma [53] in 1998 and then an exploratory factorial analysis was performed to determine the number of factors in the Spanish version following the same procedure as has been used to adapt the questionnaire to the different languages for which it has been validated [55]. The following adjustment indices were calculated to determine the general adjustment of the model: the chi-squared goodness-of-fit test, the ratio between chi- squared and the degrees of freedom (χ2/df), the Comparative Fit Index (CFI), the Goodness- of-Fit Index (GFI), the Adjusted Goodness-of-Fit Index (AGFI) and the Root Mean Square Error of Approximation (RMSEA). The criteria for a good fit were CFI, GFI and AGFI values above 0.90 [56–58], and RMSEA values were to be below 0.08 [55, 59]. Before using the EFA its suitability was tested using the Kaiser Mayer Olkin test (KMO) and the Bartlett sphericity test. For the extraction of the factors three basic rules were kept in PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 7 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp mind (a) Kaiser rule [60] retaining the components with values greater than 1; (b) the graphic inspection of scree plot [61], in which all components above the curve are removed/excluded and (c) the classical implementation of Horn’s Parallel Analysis [62], a method that adequately identifies the number of components of the questionnaire [63]. The EFA was adjusted to the polychoric correlation matrix given the ordinal nature of the items [64]. The communalities and coefficients in the matrix were also checked and coeffi- cients greater than 30 were considered significant. The adjustment function chosen for the data extraction method was weighted least squares with correctional adjustment statistics for mean and variance [65]. The factors were rotated using the Robust Promin rotation [66]. The reliability was analysed using the internal consistence evaluated with the Cronbach alpha and omega Index. Values were considered appropriate with a Cronbach’s alpha value greater than 0.70 [67]. Values that oscillate between 0.70 and 0.90 are considered adequate [68, 69], values greater than 0.90 are considered excellent [70]. Values were considered appropriate with an omega Index scale value greater than 0.80 [71]. Temporary stability or test-retest was evaluated after 2 weeks from the intra-class correlation coefficient in a sample of 257 pregnant women. The values of this coefficient oscillate between 0 and 1. The concordance is considered to be excellent when the coefficient is greater than 0.90, good if it is between 0.71 and 0.90, mediocre between 0.31 and 0.50 and poor when it is less than 0.31 [72–74]. CFA models were estimated using structural equation modelling (EQS 6.4 for Windows, Multivariate Software, Inc., Encino, CA, USA) and EFA was carried out using the Factor Anal- ysis programme [75]. Ethical considerations The study was approved by the Human Research Ethics Committee at the Germans Trias i Pujol Hospital (code PI14-074) and by the Medical Research Ethics Committee Jordi Gol (code P14/106). All the participants were informed of the aims of the study and gave their ver- bal and written consent and they participated voluntarily. The translation was completed with the express consent of the original author of the questionnaire. Results Characteristics of participants The characteristics of the participants is shown in Table 3. A total of 273 pregnant women were included in the study. The average age was 33.0 (SD 5.0) with a range of 20 to 46 years. The 65.2% were nulliparous and 3.3% declared that they had no partner. 78.0% referred to uni- versity studies and 88.6% to stable work. Construct validity Here we present the different analyses carried out to evaluate the construct validity, confirma- tory factorial analysis (CFA) and exploratory factorial analysis (EFA). Confirmatory factor analysis (CFA) Confirmatory factorial analysis (CFA) was used to verify the unidimensional structure of the original version of the questionnaire. In Table 4 the single factor model adjustment is shown, which contains 33 items from the questionnaire WDEQ-A-Sp. The model showed a deficient adjustment (for example CFI = 0.59 and RMSEA of 0.10). These results did not confirm the unidimensionality of the original structure of the questionnaire of WDEQ-A. PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 8 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 3. Participant characteristics. Characteristics n % Parity Nulliparous 178 65,2 Multiparous 95 34,8 Partner With partner 264 96,7 Without partner 9 3,3 Level of studies Primary 19 7,0 Secondary 41 15,0 University 213 78,0 Employment status Working 242 88,6 Out of work 31 11,4 https://doi.org/10.1371/journal.pone.0248595.t003 Exploratory factor analysis (EFA) Exploratory factor analysis (EFA) was carried out of the Spanish sample to test if subcategories of fear exist within the W-DEQ-A-Sp as has been done for the other different languages for which the questionnaire has been validated. The previous analysis identified 2 items with a value less than 0.30 (item 26 and item 27) that were eliminated. Seven factors had auto-values greater than 1, which explains the 69.0% of variance. However, the scree plot (Fig 1) and the results of the parallel analysis suggested 4 values for which the real data autovalues exceeded the random data autovalues. 55.3% of the variance is explained by these 4 factors. Table 5 shows the goodness of fit indexes for the 4 factor model, which are excellent. The 4 factors defined as “fear”, “isolation”, lack of positive anticipation” and “riskiness” in the UK study [34] were similarly defined in the Spanish sample. Table 6 shows the percentage of variance explained for each factor and the variables that configure each one. To facilitate the interpretation they have been ordered in function of size and factorial loading. Internal consistency and temporal stability The Cronbach’s alpha for the total of the questionnaire was 0.91 and values greater than 0.70 were obtained in all the factors making up the questionnaire. The omega coefficient (ω) for the total questionnaire and for each of the factors was greater than 0.81. Table 4. Goodness-of-fit indices for the confirmatory model W-DEQ-A-Sp. INDEX VALUE CFI 0.594 GFI 0.918 AGFI 0.907 RMSEA 0.109 Goodness of fit test χ2 = 2102,020; gl = 495; P < 0.0001 Reason for fit χ2 / gl = 4,24 CFI: Comparative Fit Index. GFI: Goodness of Fit Index. AGFI: Adjusted Goodness of Fit Index. RMSEA: Root Mean Standard Error of Approximation. https://doi.org/10.1371/journal.pone.0248595.t004 PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 9 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Fig 1. Scree plot of the W-DEQ-A-Sp. https://doi.org/10.1371/journal.pone.0248595.g001 ICC analysis demonstrated that the test–retest reliability was 0.91 (95% confidence interval 0.89–0.93) and this value was greater than 0.84 for the four dimensions. In Table 7 the results of the W-DEQ-A-Sp are shown related to reliability and the test-retest temporal stability. Table 5. Indices of goodness of fit of the exploratory factor analysis to the model for four dimensions the W-DEQ-A-Sp. INDEX VALUE 95% confidence interval CFI 0.993 0.993–0.996 GFI 0.982 0.980–0.987 AGFI 0.976 0.974–0.983 RMSEA 0.034 0.010–0.050 Goodness of fit test χ2 = 454,600; gl = 347; P < 0.0001 Reason for fit χ2 / gl = 1,31 CFI: Comparative Fit Index. GFI: Goodness of Fit Index. AGFI: Adjusted Goodness of Fit Index. RMSEA: Root Mean Standard Error of Approximation. https://doi.org/10.1371/journal.pone.0248595.t005 PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 10 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Table 6. Loading matrix related to the exploratory factor analysis solution. Item No. Description Factor 1 Factor 2 Factor 3 Factor 4 ‘fear’ ‘isolation’ ‘lack of positive anticipation’ ‘riskiness’ 19 Panic 0.873 6 Afraid 0.799 17 Relaxed 0.743 9 Safe 0.712 12 Tense 0.661 5 Confident 0.635 24 Pain 0.600 10 Independent 0.569 4 Strong 0.561 2 Frightful 0.554 8 Weak 0.530 1 Fantastic 0.501 15 Abandoned 0.841 11 Desolate 0.645 3 Lonely 0.599 7 Deserted 0.568 20 Hopelessness 0.398 25 I will behave extremely badly . 0.326 13 Glad 0.735 14 Proud 0.700 18 Happy 0.698 21 Longing for the child 0.674 30 Should be 0.632 28 Enjoyable 0.592 22 Self-confidence 0.574 29 Natural 0.568 23 Trust 0.463 16 Composed 0.335 33 Fantasies that your child will be injured during labour/delivery 0.894 32 Fantasies that your child die during labour/delivery 0.851 31 Dangerous 0.341 Percent of variance 35,34 9,77 6,51 5.60 https://doi.org/10.1371/journal.pone.0248595.t006 Table 7. W-DEQ-A-Sp Cronbach’s alpha coefficient, omega coefficient and ICC test-retest (n = 257). Factor Cronbach’s alpha Omega (ω) ICC (CI 95%) F.1. Fear 0.885 0.900 0.903 (0.876–0.924) F.2. Isolation 0.732 0.830 0.855 (0.815–0.887) F.3. Lack of positive anticipation 0.868 0.894 0.861 (0.822–0.891) F.4. Riskiness 0.719 0.819 0.849 (0.807–0.882) Total 0.918 0.936 0.917 (0.894–0.935) ICC: intraclass correlation coefficient; CI: Confidence interval. https://doi.org/10.1371/journal.pone.0248595.t007 PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 11 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Discussion The objective of this study was to translate the Wijma Delivery Expectancy/Experience Ques- tionnaire (W-DEQ-A) into Spanish and analyse the reliability and validity of the Spanish ver- sion. The original questionnaire designed by Wijma contains 33 items grouped in one single dimension. It was developed to “measure fear of childbirth by means of the woman’s cognitive appraisal regarding the delivery” [53] (p.85). In our study we initially carried out a CFA using the generalized least squares method with the aim of determining if the scores reproduced the unidimensional structure on which the original questionnaire is based. Regarding the adjustment indexes of the model: Comparative Fit Index (CFI), Goodness of Fit Index (GFI), Adjusted Goodness of Fit Index (AGFI), Root Mean Square Error of Approximation (RMSEA), and normalized Chi-squared all presented a deficient adjustment, therefore we concluded that the model does not fit conveniently. These results are consistent with many other studies on the lack of unidimensionality of the WDEQ-A [13, 33, 34, 48]. Because of this, we had to abandon the hypothesis of a single factor and explore our sample to determine which model should be expected in the Spanish population. For this we also car- ried out an EFA. We used the classical implementation of Horn’s Parallel Analysis [62]. This method is superior to the conventional methods for correctly identifying the true number of dimensions [62, 63, 76]. The results of the analysis have suggested 4 factors, or dimensions, which are similar to, but not identical to those obtained in other factor analysis studies of WDEQ-A [13, 33, 34, 38, 41, 48]. However, of all the studies which have identified four factors, that which was most similar to ours was that of the United Kingdom (UK) [34]. In both studies 31 items have presented a factorial load superior to 0.30 and have grouped together in four dimensions in a very similar way. The explained variance of the structure with four dimensions was 55%. This variance was very similar to that found in the majority of studies that have validated this questionnaire [13, 33, 34, 37, 41–44, 47] and was only less than that found in the study carried out by Abedi et all., Moghaddam Hosseim et al. y Pitel et al. [45, 46, 49]. Although the percentage of explained variance found in this study could be considered to be low, it is not currently recom- mended to use the interpretation of explained variance as the only indicator of factors identi- fied. Rather it is recommended to incorporate procedures based on Parallel Analysis, which selects common components or factors that present own values higher than those expected by chance, as for example, the Minimum Average Partial test, or the RMSEA adjustment indica- tor [77, 78]. In this study both Parallel Analysis and the RMSEA have been used to identify the adequate number of factors. To analyse the reliability of the questionnaire an analysis of its internal consistency was car- ried out using the Cronbach’s alpha coefficient. The total Cronbach’s alpha value for the ques- tionnaire was 0.91 (considered excellent), with factors varying between 0.71 and 0.88, so that all the dimensions were adequate. The fact that the internal consistency is greater than 0.90 can be interpreted as meaning that there are redundant elements in the questionnaire. However, according to Kottner et al. (2011), for an instrument to be able to be used to take clinical decisions, the minimum Cron- bach’s alpha acceptable should be 0.90 [79]. Furthermore, these values are very similar to those obtained in other studies in which the reliability was measured with the Cronbach’s alpha coef- ficient [13, 34, 42, 45, 47, 49]. Additionally in this study the homogeneity coefficient was calcu- lated for the corrected items estimating the correlations of each item with the total scale and PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 12 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp with its corresponding subscale. In this study a correlation of 0.20 was accepted as the inferior limit [80]. In this study the reliability has also been analysed using the omega coefficient (ω) which is recommended when one dimension has few items. Factor four (Riskiness) consists of three items, so it was decided to calculate this coefficient as a complementary method. Values greater than 0.80 are considered adequate. The omega coefficient in this study was satisfactory for both the total questionnaire and each of the four dimensions with values greater than 0.80 for all of them [71]. The temporal stability or test-retest has also been analysed in this study. The temporal sta- bility of the WDEQ-A questionnaire has not been checked in any other validation study. Of the 273 pregnant women who participated in this study 257 completed the questionnaire again on a separate occasion after two weeks. The ICC obtained for the total questionnaire and for each of the dimensions was good with values greater than 0.80 for each of the dimensions of the questionnaire [72–74]. Limitations This study has several limitations that should be taken into account. Firstly, all the pregnant women who participated in the study did so voluntarily and were selected consecutively by their midwives, so the selection could be biased. However, a large number of pregnant women from different centres in Barcelona were included and their sociodemographic and clinical characteristics are very similar to the rest of the pregnant women in the Spanish population so that these results can be generalized. Secondly, sensitivity to change has not been studied in the Spanish population, but it would be interesting to research this in future longitudinal or post-intervention studies. Conclusions The Spanish version of the WDEQ-A (WDEQ-A-Sp) is the first instrument to be validated in Spanish for the screening of fear of childbirth. The results of this study confirm the findings of other studies that suggest that the WDEQ-A is multi-dimensional. In the Spanish version of the WDEQ-A-Sp four dimensions have been identified that make it possible to explore fear of childbirth in pregnant women (fear’, ‘isolation’, ‘lack of positive anticipation’ and ‘riskiness’). It is a multidimensional questionnaire, which is easy to complete and with good psychometric properties in terms of reliability and construct validity; making it suitable for implementation in clinical practice. More studies with a larger sample size and developed in other areas of Spain are needed to assess the prevalence of fear of childbirth in the Spanish population. Like- wise, having a validated instrument would allow future research to be carried out into fear of childbirth in order to implement interventions to reduce it. Finally, the statistical techniques used in this study allow us to add together solid evidence to back up the use of this question- naire in the Spanish population. Supporting information S1 Data. (XLSX) Acknowledgments We thank all the pregnant women who have participated in this study and the midwives of the participating centres. PLOS ONE | https://doi.org/10.1371/journal.pone.0248595 March 19, 2021 13 / 17 PLOS ONE Reliability and validity study of the W-DEQ-A-Sp Author Contributions Conceptualization: Celia Maria Ortega-Cejas, Juan Roldán-Merino, Sandra Cabrera-Jaime. Data curation: Celia Maria Ortega-Cejas, Mª Isabel Castrillo-Pérez, Mª Mercedes Vicente- Hernández, Marta Jimenez-Barragan, Ainoa Biurrun-Garrido, Mariona Farres-Tarafa. Formal analysis: Celia Maria Ortega-Cejas, Juan Roldán-Merino, Irma Casas, Sandra Cab- rera-Jaime. Investigation: Celia Maria Ortega-Cejas, Juan Roldán-Merino, Teresa Lluch-Canut, Mª Isabel Castrillo-Pérez, Mª Mercedes Vicente-Hernández, Marta Jimenez-Barragan, Ainoa Biur- run-Garrido, Mariona Farres-Tarafa, Irma Casas, Sandra Cabrera-Jaime. Methodology: Celia Maria Ortega-Cejas, Juan Roldán-Merino, Teresa Lluch-Canut, Sandra Cabrera-Jaime. 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