This sequential, exploratory mixed methods research had two phases: Descriptions of these are provided as follows:
Phase 1: Item generation and questionnaire development
A conventional qualitative content analysis was designed to determine the concept and dimensions of the married adolescent women's sexual and reproductive health needs. The research was conducted from November 2017 to June 2018 in Mashhad city (healthcare centers) and Shahrood County (a maternity teaching hospital and urban/rural healthcare centers), Iran. Data were collected using semi-structured, in-depth interviews with 34 married adolescent women and 4 healthcare providers. In the interviews, married adolescent women were asked the following questions: "What does sexual and reproductive health mean to you?"; "What are the sexual and reproductive health needs of married adolescent women?"; "What are the barriers and challenges faced by married adolescent women in accessing and utilizing reproductive health services?"; "Have you ever experienced such challenges?"; "What major challenges did you face, and how did you handle them?". Healthcare providers were asked the following interview questions: "What are the sexual and reproductive health needs of married adolescent women?"; "What are the barriers and challenges faced by married adolescent women in accessing and utilizing reproductive health services?". Each interview lasted between 30 and 80 min. All interviews were audio-recorded with the participants’ permission and transcribed verbatim for analysis. MAXQDA software (Version 10) was used to facilitate data management.
Then, the following databases were searched for relevant papers: Web of Science, PubMed/Medline, Scopus, and Science Direct. Google Scholar was also searched for any pertinent studies that may not have been found in the database search.
Key search terms used were as follows: ‘child marriage’, ‘early marriage’, ‘married adolescent women’, ‘adolescent women’, ‘adolescent mother*’, ‘teenage mother*’, ‘adolescent’, ‘teenager’, ‘young mother*’, ‘adolescent pregnan*’, ‘teenage pregnan*’, ‘maternal health’, ‘antenatal care’, ‘prenatal care’, ‘postnatal care’, ‘skilled birth attendan*’, ‘delivery’, ‘obstetric care’, ‘STD’, ‘sexual transmited disease’, ‘unwanted pregnancy’, ‘health seeking’ ‘family planning methods’, ‘need*’, ‘reproductive health needs’, ‘sexual health needs’, ‘reproductive tract infections’, ‘RTI’, ‘health care seeking’, ‘pregnancy complications’, ‘early pregnancy’, ‘contraception’, ‘community support’, ‘reproductive health service’, ‘social support’, ‘support*’, ‘domestic violence’, ‘partner violence’, ‘violence*’, ‘IPV’, ‘intimate partner violence’, ‘information’, ‘knowledge’, ‘information seeking’, ‘experience’, ‘barriers*’, ‘decision-making’.
Extracted codes from the interviews and a review of the literature led to an initial questionnaire with 137 items. After several modifications of the generated items, a 108-item questionnaire was prepared for the next stage.
Phase 2: Psychometric properties of the questionnaire
In this phase, the validity (face, content and construct validity) and reliability (internal consistency and test-retest reliability) of the designed questionnaire were assessed. Details are as follows:
1. Face validity
Qualitative and quantitative methods were used to determine face validity. In qualitative assessment of face validity, 10 married adolescent women were recruited using convenience sampling to determine complexity, relevance, and ambiguity of the items. Then, the items were modified according to the married adolescent women's viewpoints.
For quantitative face validity assessment, the same adolescent women rated the importance of each item on a 5-point Likert scale. Then, the impact score for each item was calculated using the following formula: (frequency (%) × importance). Frequency reflects the percentage of raters who scored a score of 4 or 5, and importance reflects the mean score for the importance of each item. Items with an impact score of greater than or equal to 1.5 (which corresponds to a mean frequency of 50% and a mean importance of 3 on the 5-point Likert scale) were considered appropriate (13).
2. Content validity
For analyzing qualitative content validity, 10 experts in the fields of midwifery and reproductive health were requested to assess grammar, wording, item allocation, and scaling of the questionnaire. Then, items were amended based on their comments.
Quantitative assessment of content validity was done by calculating content validity ratio (CVR) and content validity index (CVI).
To determine CVR, the same ten experts were asked to score each item on a 3 - point Likert scale: 1 = not essential; 2 = useful, but not essential; and 3 = essential. The CVR for each item was calculated using the following formula: CVR = (ne – (N/2)) / (N/2). In this formula N is the total number of experts and ne is the number of experts that rated the item as essential. According to Lawshe's table, items with a CVR greater than or equal to 0.62 were retained (14). For calculating CVI, the same ten experts were asked to rate each item based on relevance, clarity, and simplicity on a 4-point Likert scale (rating from 1[not relevant/ not clear / not simple] to 4[highly relevant/ highly clear/ highly simple]) (15). The CVI was calculated for individual items (I-CVI) and the overall scale (S-CVI). The I-CVI was calculated as the proportion of experts who rated the item as 3 or 4 (16). The S-CVI was calculated as the average value of all the I-CVI values (16). Content validity indexes were considered acceptable when I-CVI and S-CVI were at least 0.78, and 0.90, respectively (16, 17). To counter the limitations of CVI, each I-CVI was adjusted for chance agreement by calculating the modified kappa statistic (κ*). To compute the modified kappa statistics, the probability of chance agreement was computed first: Pc = (N/A (N − A) × 0.5N, where N denotes the number of experts and A denotes the number of experts who agree that the item is relevant. Then, the κ* was calculated using the following formula: κ* = (I-CVI − Pc) / (1 − Pc) (16). K values are categorized as: [poor <0.4]; [fair 0.40 to 0.59]; [good 0.60 to 0.74]; [excellent >0.74] (16, 18).
3. Construct validity
Exploratory factor analysis (EFA) was performed in order to assess the construct validity of the questionnaire. The required sample size for conducting EFA is 3–10 subjects per item (19). Therefore, for 85-item questionnaire, a sample size of 85 × 3 = 255 was estimated; however, in practice 248 married adolescent women participated in the study and completed the questionnaire. Census method was used to recruit subjects from urban/rural healthcare centers in Shahrood County and Miami County of Semnan province, northeast Iran (July to November 2020). The inclusion criteria were: having Iranian nationality; being 10 to 19 years old; being married; living in Shahrood County or Miami County; given birth to ≥ 1 child or being pregnant with a gestational age of ≥ 20 weeks; and willingness to participate in research. Married nulliparous adolescents (who had never been pregnant or had never carried a pregnancy beyond 20 weeks) were not included in the study. Kaiser-Meyer-Olkin (KMO) was used for checking sampling adequacy and Bartlett’s test of sphericity was used to examine the appropriateness of data for factor analysis. The KMO value should be greater than 0.5 and result of Bartlett’s test of sphericity should be statistically significant with a p value less than 0.05 (20). Principal components analysis (PCA) with varimax rotation was conducted to extract the underlying factors (21). Factor loadings greater than or equal to 0.3 were considered appropriate (22). The number of factors was extracted based on eigenvalues greater than 1 and then see the scree plot. All statistical analyses were performed using SPSS software, version 22.0 (SPSS Inc., Chicago, IL, USA).
4. Internal consistency
The internal consistency for each dimension and the entire scale was assessed using the Cronbach’s alpha coefficient. Values equal to or greater than 0.7 were considered acceptable (23).
5. Test-retest reliability
In order to assess test-retest reliability, 20 subjects completed the questionnaire twice with a 2-week interval. Test–retest reliability of the questionnaire was determined by calculating intraclass correlation coefficients (ICC), and its results were interpreted as follow: 0–0.20 as poor; 0.21–0.40 as fair; 0.41–0.60 as good; 0.61- 0.80 as very good; and 0.81–1 as excellent (19).
Ethics
The study protocol was approved by the Ethics Committee of Shahroud University of Medical Sciences with the ethical code: IR.SHMU.REC.1396.69. All subjects gave informed consent prior to participation in research.