This study was a randomized clinical trial. Participants were 80 new married couples (not more than 6 to 12 months after their marriage), whose information was recorded at the premarital counseling centers, who were randomly (with simple randomization) divided into intervention and control groups. 80 consecutive numbers (one for each couple) were written on a separate piece of paper and placed in a container.Selected even numbers went to group A (control) and selected odd numbers to group B (intervention). To equalize the number of selections in the groups, the removed numbers were not returned to the container.
In order to perform concealment in the randomization process, the research colleague (one of the center midwives) was asked to cooperate to perform the group assignment, without knowing the nature of even or odd numbers in order to select individuals in the intervention or control group. Although the data analyst was unaware of the allocation of code to the groups, blinding was not possible in this study due to the researcher's knowledge of the groups and their implementation of the intervention. The consort diagram can be seen in Figure 1.
Cognitive behavioral counseling was done with a protocol adjusted by Ellis method's in 8 sessions (120 minuts) in intervention group [17-18]. The control group only had a history of attending premarital counseling session. The history of participating in this session were common to both groups. Also before starting the practical process of research, the validity of the content of sessions, both formal and logical, based on the viewpoints of experts, was evaluated by professors of Kermanshah and Kurdistan University of Medical Sciences.
The study sample size was calculated according to the formula. The sample size in each group of intervention and control, was set 80 ones (40 couples) with α=0.05 and β=0.20.
Inclusion criteria included: age 20 to 35 years old from both genders, to have sexual medium compatibility with a score of 62 to 96 using National Sexual Compatibility Scale [19], married for at least 6 months and maximum one year, no history of drug, alcohol and sexual enhancement drugs use, no history of treatment by a psychologist or urologist or gynecologist for sexual dysfunction, no genetic abnormalities in anatomy and sexual function, no previous marriage, no infertility or diseases ( like diabetes) and medications such as drugs that affect sexual function, minimum literacy (elementary) and not pregnancy. Exclusion criteria included unwillingness to continue in the study, failure to attend two or more sessions, incomplete answers or semi- completion of the questionnaire and adverse event in couples' lives (beloved ones’ death, events with disability). Data were collected before the intervention, after 8 weeks of counseling, and two months after the last counseling session using National Sexual Compatibility Scale.
Research Tools
The National Sexual Compatibility Scale was prepared in Ph.D. thesis mentioned. The sexual compatibility scale is a 33-item tool that has been providing by Nekoolaltak to assess sexual compatibility [19]. This scale is completed by person himself and has 33 main items and 15 demographic items. The first 15 items are demographic information and the next 33 items are about the history and how to have sex which helps to understand the context of one's sex life. Scale scoring is according to the main items. The Likert scale is used to score each item, as follows: consistently (4), often (3), sometimes (2), and never (1)/ very much (4), much (3), low (2) and very low (1). About reverse items (28_27_26), the method of scoring was opposite the above items. Subjects in item numbers (15-14-13-12) could answer more than one option. Scale classification was as: poor (33-61), moderate (62-96) and desirable (97-132). Scale lower than 33 was no compatibility.
Reliability was measured by internal consistency using Cronbach’s alpha and test-retest. Cronbach’s alpha for the entire questionnaire was obtained 0.90. Correlation coefficient in the test-retest method was 0.91. Qualitative and quantitative content validity was evaluated with the participation of 16 experts (12 women and 4 men) from different fields, including 8 reproductive and sexual health experts, 2 psychologists, 1 psychiatrist, 2 sociologists, 2 gynecologists and 1 nurse. Five experts had a history of instrument construction. In quantitative content validity, the specialists scored the necessity of each item within 1 to 3 ranges and accordingly, content validity ratio (CVR) was calculated and compared with Lawshe’s CVR table [19]. Then, the specialists scored the relevance of each item from 1 to 4 and content validity index (CVI) was calculated according to the formula presented by Waltz and Bausel [20]. The amount of CVR and CVI for each items were seen in table 5 of psychometric article of Nekoolaltak Sexual Compatibility Scale [19].
This study was approved by the Research Ethics Committee of Kermanshah University of Medical Sciences (IR.KUMS.REC.1397.516) and registered in the Iranian Registry of Clinical Trials (IRCT 20181006041254N1). Study participants were allowed to exit the study at any stage. The researcher explained the objectives of project to subjects and their satisfaction and cooperation and identified the volunteers who had the inclusion criteria. Signed written consent was obtained from the participants after the researcher's complete explanation. Data were analyzed using SPSS software version 19. To determine the descriptive purposes of study, the calculated frequency, mean and standard deviation according to the type of variable. Chi-square inferential-statistics tests and independent t-test or nonparametric equivalent namely Mann-Whitney tests were used for analytical purposes. analysis of covariance was also used to control the potential confounders.