This quasi-experimental study, using a two-group pretest-posttest design, was conducted on 80 married female students studying at a University in southeastern Iran from January to June 2017. This study was approved by the Ethics Committee of Zahedan University of Medical Sciences, Iran, under the code of IR.ZAUMS.REC.1395.244. After participants were notified about the research procedure, objectives, as well as duration and type of intervention, the written informed consent form was obtained from the subjects and their spouses. In addition, they were assured about the confidentiality terms regarding their personal information and the possibility of withdrawing from the research at any time.

The inclusion criteria were: 1) a minimum of one year elapse from marriage; 2) age range of 18-40 years; 3) not mastering in the fields of psychology or counseling; 4) no history of psychiatric diseases; 5) non-consumption of medications affecting sexual performance; 6) lack of physical diseases or surgeries affecting sexual performance; and 7) lack of extreme marital conflicts (e.g., threats of divorce or separation). On the other hand, those who did not attend more than one counseling session were excluded from the study.

The sample size was estimated as 40 individuals per group (n=80 in total) by considering the mean and standard deviation reported by Padash et al. The sample size was determined at the confidence level of 0.095%, the test power of 0.95%, and considering sample dropout [19].

At first, a public announcement was made by the Student and Culture Deputy of the university regarding the implementation of student sexual counseling sessions, and then a list of married female students was prepared. Subsequently, the eligible individuals were divided into two groups of intervention (n=40) and control (n=40) through simple random sampling. The envelopes were randomly distributed and an enclosed envelope indicating the respective group of each individual (A for intervention and B for control) were provided to all participants. The envelopes were given to the participants in order. The data was collected using a questionnaire, consisting of three sections, namely demographic information, Sexual Assertiveness Questionnaire, and the ENRICH Marital Satisfaction Scale. The demographic section included age, field of study, duration of marriage, number of children, age, occupational status, and education level of the spouse.

The Hurlbert Index of Sexual Assertiveness was first designed by Hurlbert in 1991 to estimate the level of sexual assertiveness of women in interacting with others. This 25-item questionnaire was reported to have an internal consistency of 0.91. The minimum and maximum possible scores of this index are 0 and 100, respectively, with higher scores indicating a higher sexual assertiveness and lower scores denoting a lower sexual assertiveness [20]. This scale, used in several studies as a valid research tool [13,18,21], is rated on a five-point Likert scale {Always (4); Most often (3); Sometimes (2); Rarely (1); and Never (0)}.

ENRICH Couple Scales (ECS): This questionnaire was developed by Olson in 1985 and updated in 2010. It comprises of 35 items and 4 sub-scales including marital satisfaction, communication, conflict resolution, and idealistic distortion. Alpha coefficients for the sub-scales of marital satisfaction, communication, conflict resolution, and idealistic distortion equal 0.86, 0.80, 0.84, and 0.83 respectively. Besides, its test retest reliability was equal to 0.86, 0.81, 0.90, and 0.92 respectively. The answer to the questions of this questionnaire could be one of the five options: fully agree (5); agree (4); neither agree nor disagree (3); disagree (2); completely disagree (1). It should be mentioned that some questions are scored in reverse. By adding the scores of all items of the questionnaire, a total score of at least 35 to a maximum of 175 is obtained. These scores are converted to a score between 0 and 100, so that a higher score indicates higher marital satisfaction and viceversa. Fowers and Olson have used this questionnaire to examine marital satisfaction, and they believe that this scale is sensitive to changes in the family [22]. In Iran, the validity and reliability of the Persian version of this tool have been confirmed by Asodeh et al., and Abbasi et al., and used in Iran [23,24]. The reliability of this tool in the present study was obtained with the help of Cronbach’s alpha for its four subscales (68%, 78%, 62%, and 77% respectively). In Iran, the reliability and validity of the Persian version of this tool were confirmed by Asoodeh et al., and Abbasi et al., accordingly, it has been used in several studies [23,24]. The Cronbach’s alpha coefficients for the whole questionnaire in the studies by Asoude et al., and Abbasi et al., were 0.91 and 0.84, respectively, and it was 0.74 in the present study.

In order to prevent the distribution of the educational and counseling information among the subjects of the intervention and control groups, the data of the control group were collected at the end of the academic semester, and the members of this group were added to the waiting list to receive the counseling session after the research for the next semester. On the other hand, the participants of the intervention group were divided into groups of 6-8 participants, and completed the ENRICH Marital Satisfaction Scale and the demographic form as a pretest. In total, four sessions were held in two weeks time and each session was of 2 hours. The intervention was presented by a graduate with Master of Midwifery Counseling and clinical work experience under the supervision of a specialized counseling doctor (family counselor) with many years of working experience in the domain of psychological counseling. After 12 weeks post-intervention, the subjects were invited to the Counseling Center of the university to collect data in the posttest stage.

The basis of intervention in this study was sexual group counseling on assertiveness, which was designed according to the review of the related literature and asking the opinions of clinical psychology specialists, family counselors, and psychiatrists, who were experienced in the treatment of sexual disorders. Sexual relation training was carried out with an emphasis on the concept of assertiveness, especially sexual assertiveness. The intervention was performed to "promote sexual knowledge, dispel sexual clichés, and advocate assertive behaviours so as to boost sexual pleasure and satisfaction and enhance marital life in general." The content was designed in the form of a workshop, and each session included review of the previous session, introduction, presentation of the content through lecture (whiteboard and PowerPoint), videos, short animations, images, discussion on sexual beliefs and stereotypical roles of women with respect to culture and religion, as well as question and answer rounds. To access the content of the sessions, educational CDs were given to all participants at the end of the intervention sessions. Furthermore, a specific telephone line was used solely for answering emergency questions and resolving any possible marital problems caused by the educational intervention. However, due to the short interval between the sessions, no phone call related to the educational content was received. The contents of each session are illustrated in [Table/Fig-1].

Data analysis was performed in SPSS, version 21. At first, frequency, percentage, mean, standard deviation, minimum, and maximum were determined using descriptive statistics. In addition, the paired t-test was applied to compare the means before and after the intervention in each group, and the independent t-test was used for comparing the means between the two groups. Moreover, the Chi-square test and Analysis of Covariance (ANCOVA) were run to respectively compare the frequency of qualitative variables in both groups and find out the effectiveness of group sexual assertiveness counseling sessions on marital satisfaction.

The results of the Shapiro-Wilk test on marital satisfaction scores demonstrated the normal distribution of data. Therefore, the use of parametric tests in this study was allowed. The mean age of women in the intervention and control groups were 22.30±2.81 and 22.47±3.10 years, respectively. Furthermore, the mean ages of their spouses in the two groups were 26.58±3.37 and 26.67±3.69 years respectively.

According to the results of the independent t-test, there was no significant difference between the groups in terms of the mean ages of the women and those of their spouses (p>0.05). Moreover, no statistically significant difference was observed between the two groups regarding the demographic characteristics of the subjects and their husbands (p>0.05) [Table/Fig-2].

Based on the results, the mean of female sexual assertiveness changed from 45.84±14.43 to 65.90±15.44 in the intervention group and from 46.32±15.12 to 47.02±13.85 in the control group [Table/Fig-3]. Independent t-test revealed that the mean increase in sexual assertiveness scores in the intervention group was significantly higher than in the control group (p=0.0001).

According to [Table/Fig-4], the increased mean changes of the women’s marital satisfaction total score in the intervention group (+9.29±8.1) was significantly higher, compared to that of the control group (-3.71±5.42, p<0.001). Controlling the confounding effect of the pretest, the results of the ANCOVA demonstrated that the mean total score of the women’s marital satisfaction in the intervention group was significantly higher in the posttest stage, compared to that in the control group [Table/Fig-5]. This finding is indicative of the positive impact of the sexual counseling sessions on the improvement of marital satisfaction.

The participants were surveyed regarding the educational intervention, and 87.5%, 7.5%, and 5% expressed complete, relative, and low satisfaction respectively. Further, 90% said that they would recommend these kinds of training programs to their friends. They suggested that it is better to provide these informal educations before marriage and to involve men in the training sessions so they might recognize women’s sexual rights.

This study was conducted with the aim of determining the effect of group sexual assertiveness counseling on marital satisfaction of married female students. As the findings of the present study indicate, sexual counseling about assertiveness leads to a significant growth in the sexual assertiveness and marital satisfaction of the subjects. In this regard, Rahmani et al., demonstrated a positive association between sexual satisfaction and marital satisfaction [25].

In the present study, sexual counseling resulted in the enhancement of sexual satisfaction, which in turn improved the marital satisfaction of the couples. In a study conducted by Lee et al., the absence of sexual assertiveness in women was one of the predictive factors for the lack of marital satisfaction [12]. In this regard, Woerner and Abbeya have observed that sexual assertiveness can predict sexual pleasure, which is associated with positive excitements in marital relations [26]. Therefore, the emphasis on sexual assertiveness in sexual teaching can help in raising marital satisfaction. This is in line with the findings of the current research.

Consistent with these results, Asadi et al., affirmed that among the variables associated with sexual activities, decreased sexual assertiveness leads to the rise of marital disappointment and the growth of this assertiveness mitigates marital disappointment [27]. This is mainly due to the fact that women, who share their sexual desires, needs, and feelings with their spouses and have a high sexual intimacy, have greater sexual relations, which in turn improve marital satisfaction [20].

In addition, in the present study, group sexual assertiveness counseling led to the enhancement of autonomy and self-efficacy in married women. Likewise, in a study conducted by Vaziri et al., sexual self-efficiency was reported to have a significant relationship with increased marital satisfaction [28]. In another study performed in Iran, Nazari et al., investigated the effect of feminist group sexual therapy on educated married women aged 20-35 years [17]. According to their results, sexual teaching improved sexual right recognition and marital satisfaction in these females. The results of the study of Nazari et al., and the present research demonstrate that sexual teaching of women with an emphasis on sexual clichés and recognition of women’s sexual rights by the women and their spouses not only result in the elevation of sexual satisfaction in men and women, but also improved the relationship and satisfaction of couples. The women’s preparedness, cooperation, and positive emotional expression in a sexual relationship elevate the sexual relations from a mechanical state and enhance the spouses’ passions during the sexual relationship, which in turn improve the sweetness of the relationship.

Previous studies have shown that women with low levels of sexual assertiveness express their sexual desires less frequently and experience more unwanted sexual relations. In contrast, women who are fully aware of their sexual rights experience more sexual activities, orgasm, sexual tendencies, and sexual satisfaction; as a result, they have better sexual satisfaction scores [10,17,29,30]. Studies suggest that sexual assertiveness or the ability to express sexual desires is one of the most influential factors in sexual performance as well as marital satisfaction quality [31]. In a study carried out by Lee et al., it was indicated that sexual assertiveness can be a positive and unique predictor of students’ marital satisfaction, especially in societies where sexual assertiveness is not emphasized or encouraged [12]. It seems that in the cultures in which discussing sexual subjects is considered taboo, especially for women, even married women and men have no desire to talk about these issues, sexual teaching with any content might increase sexual knowledge, sexual satisfaction, and marital satisfaction in the couples. Accordingly, many studies have corroborated the remarkable usefulness of such related educations.

In a research carried out by Chang et al., it was indicated that women with decreased sexual assertiveness responded positively to education and counseling. Accordingly, they demonstrated that the influence of a six-hour education about sexual assertiveness on the enhancement of females’ sexual assertiveness was similar to that of three-hour training in this study [32]. According to Balon, female sexual inefficiency has a significant and inevitable effect on their marital relationship and welfare [33]. Therefore, it is necessary to explore proper therapeutic plans while considering the main and latent variables of sexual performance, such as assertiveness and cultural conditions of any society.

The majority of studies conducted in Iran have focused on the provision of sexual teaching in a general manner for the couples with sexual problems, and they have paid little attention to the issue of sexual assertiveness in healthy couples. Given the cultural, religious, and social concerns of Iranians and relative lack of sexual assertiveness, especially in women, the presentation of sexual counseling with an emphasis on the enhancement of sexual assertiveness was one of the positive points of the present study.

Although the core of the intervention was assertiveness, especially question and answer rounds, other sexual issues such as the correct way of sexual relationship, sexual disorders, normal sexual desire, sexual response cycle, intercourse positions, and sexual misconceptions were raised by the participants. These issues could influence sexual relationship and increase couples’ satisfaction, especially in Iran, where access to valid sex-related resources and formal sex education is limited.

In this study the male companion did not participate in the session, is one of the limitations. The authors recommend training couples in pairs or groups or holding simultaneous single-gender workshops. Furthermore, examining the effect of training sexual assertiveness on other sexual implicit and explicit variables can be beneficial. Considering that sexual issues, in particular sexual assertiveness, are subject to individual, social, and cultural variables, caution should be taken in generalizing the findings of this study to women from other academic, cultural, and religious backgrounds. Given the religious limitations of the Iranian society, teaching was provided only for women in the form of group counseling sessions, which is regarded as one of the drawbacks of the study. Therefore, future studies are recommended to implement these teachings for the couples in the form of group sessions to obtain possibly greater effects. Another limitation of this study was the failure to measure the durability of the positive results of this study in the long run.

Healthy sexual relations and desires positively affect marital satisfaction, resulting in the improvement of mental health and the formation of healthy families. In this respect, it seems necessary to widely promote sexual assertiveness teachings, especially in communities where women have a generally low sexual assertiveness and there is a high prevalence of patriarchal sexual stereotypes (e.g., many countries of Asia, including Iran). It is recommended, moreover, that these educations be integrated with common premarital educations in these countries.

Authors’ contributions

All the authors contributed to the conceptualization and development of the study as well as the interpretation of the data. Furthermore, they all reviewed and edited the manuscript and approved the final draft and supervised the study.