The study uses a so-called pathway analysis in which all possible factors are put in to find out that indeed all factors contribute to different functions assessed in the FSFI. Recently, several studies were conducted to explore the factors affecting the SF of women with endometriosis (6, 11, 12, 24). There is controversy regarding the strength of the relationship between physical and psychological variables and women's SF due to uncontrolled interrelationships with various effects of modifiers, mediators or confounding variables on SF of endometriosis women.
To our knowledge, this survey is the first research that simultaneously evaluated the hypothesis that physical and psychological consequences of endometriosis are related to SF of women.
The results of the present study indicated that sleep quality, the intensity of pelvic pain and dyspareunia, physical activity, stage of endometriosis, anxiety, and depression were significant impacting SF in women with endometriosis.
In women with endometriosis, deep dyspareunia is a common symptom. Dyspareunia can be triggered by mechanical pressure on endometriotic lesion during intercourse or by traction of scarred and anelastic endometriotic lesion. Pain during intercourse can increase the risk of another type of sexual dysfunction (such as disorders in desire, lubrication, arousal, and orgasm) (25). In Evangelista et al.’s study, endometriosis women had more dyspareunia than healthy women. However, there was no significant relationship between total FSFI score in women with and without endometriosis (26). While in Tripoli et al study (9), chronic pelvic pain related to endometriosis or other gynecologic disorders led to a reduction in female SF (reduces the frequency of vaginal intercourse, orgasms, and sexual satisfaction) and QOL. Mauro Cozzolino et al. reported that there was no significant difference between mean FSFI scores of the two groups (with and without pain), only endometriotic lesions at the rectovaginal site, was associated with more impaired sexual activity and SF (24). The result from the Shum study demonstrated that worse sexual quality of life was associated with severe deep dyspareunia, severe superficial dyspareunia, increased depression, higher pain catastrophizing, bladder pain syndrome, and heterosexual orientation (10). In one qualitative study, endometriosis-related dyspareunia had a negative impact on women’s lives (such as avoiding sexual activity, reduced self-esteem, and quality of couple relationships) (27).
In these patients, dyspareunia is not the only determinative factor of sexual health. Many factors such as chronic pelvic pain, advanced endometriosis stage and the presence of psychological and physical comorbidities, personality traits and women’s expectations affect women's SF (16). The result of the present study showed that anxiety and depression have more impact on the SF of women with endometriosis; a higher score indicates a more negative effects on women’s SF. Our results are inconsistent with the finding of some similar studies conducted in other countries (28-32). Graaff et al.’s study demonstrates, dyspareunia and depressive symptoms in women with endometriosis have a negative impact on SF, however, their male partner's SF is not affected by women's disease (28). The results of Finn et al.'s study on the level of sexual satisfaction in men and women with chronic pain demonstrates when psychological variables such as anxiety on sexual satisfaction are considered, variables of physical such as pain accounts for very low additional variance (33).
Our findings further showed that physical activity was the variable that significantly affected the SF of women with endometriosis. In women, increased endocrine factors (such as estrogen, oxytocin, testosterone, and cortisol) and alpha-amylase level (as a marker of sympathetic nervous system activity) following exercise can improve physiological sexual arousal (34). In the other hand chronic exercise is related to the improvement of body image and psychological factors that increase sexual well-being (34, 35).
To our knowledge, the influencing factors on sexual dysfunction in Iranian women with endometriosis have not been assessed before. The combination of the evaluated domains (anxiety, sleep, depression, pelvic pain, endometriosis stage) is the major strength of this study as endometriosis is already well known to show interactions with each domain separately. Other strengths of the current study include confirmed diagnosis through laparoscopy, a developed conceptual model (path diagram in Figure 1), and the use of validated questionnaires (eg, FSFI, HADS, VAS scale, PSQI, etc.).
Despite the strengths of this study, the results have some limitations. One of the limitations of this study is that we did not consider the impact of other variables which can affect SF (such as hormonal level, love, Intimacy, partner violence, and intrapersonal relationship, etc.). It has been suggested that future studies consider these issues. The selection of patients who are all recruited from an infertility unit is another limitation of this study. Suffer from infertility itself is a risk factor of sexual dysfunction with complex dynamics depending on the duration of infertility, cause of infertility and chosen treatment with the invasiveness of the procedure, financial burden, etc.
In many Asian countries, sexual issues are overlooked, ignored and considered taboo (36, 37). Regarding the religion and culture of Iranian women, talk about sexual behaviors are considered as stigma and embarrassment, thus there might be a social desirability bias among the subjects (38, 39). Also, we did not use a validated tool for the evaluation of physical activity. Our results only apply to married women as we excluded unmarried women.