Multiple sclerosis (MS) is an inflammatory disorder affecting the central nervous system with a typical onset between 3rd and 4th decade of life. Sexual dysfunction (SD) is considered to be one of the most common symptoms of MS, including loss of libido, problems in arousal, orgasm and lubrication, dyspareunia, and dissatisfaction with sexual life. Sexual difficulties can arise directly as a result of MS lesions (primary SD), consequent to neurological disabilities (secondary SD) or resultant psychosocial issues (tertiary SD).  The interrelationship between these different factors and possible therapeutic interventions have been poorly explored. A systematic review was conducted to answer the following questions: 
(1) What is the prevalence of sexual dysfunction in female patients with MS?, 
(2) What are the patterns of sexual difficulties reported by women with MS?, 
(3) What are the interventions that have been evaluated for managing SD in women with MS?

: The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement was followed for review of publications. The protocol for this review has been registered with PROSPERO (CRD42017060620: http://www.crd.york.ac.uk/PROSPERO). The following keywords were used in the search strategy:  “neurogenic sexual dysfunction” AND “multiple sclerosis” AND “sexual dysfunction” OR “sexual symptom” OR “sexual disorder” OR “sexual satisfaction” OR “sexual function” OR “female sexual dysfunction” AND “treatment” OR “management” OR “symptoms”. The  Cochrane Database of Systematic Reviews (The Cochrane Library); MEDLINE; EMBASE; CINAHL; AMED; PsycINFO; PEDro (Physiotherapy Evidence Database); Database of International Rehabilitation Research; Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library, latest issue);  Occupational Therapy Systematic Evaluation of Evidence (OTseeker); ClinicalTrials.gov; Current Controlled Trials (http://www.controlled-trials.com/) were searched until April 2017. No limitations were placed on a date. Studies reporting the prevalence, pattern, and treatment options (either pharmacological or non-pharmacological) of sexual dysfunction in female patients with multiple sclerosis were included. Non-original articles, not published in English, conference abstracts, and publications involving children, male, not relevant outcomes, non-human studies, systematic or narrative reviews were excluded. Risk-of-bias and confounder assessment were performed by The Quality Assessment Tool for Quantitative Studies (The Effective Public Health Practice Project – EPHPP). Two authors independently assessed the eligibility of all studies and extracted data on study design, population characteristics, patterns of sexual dysfunction, measurement instrument, and prevalence rates.

The search came up with 481 studies, however only 50  (29 observational, 13 case-control, 8 interventional) publications covering a total of 19,105 people with MS and 1000 healthy controls were identified a relevant. Sexual functions were evaluated using the FSFI (39%) or MSISQ-19 (21.5%) in most studies. Prevalence rate was reported in 27 studies and ranged from 28.3% to 91%. Most commonly reported sexual difficulties were problems with desire (5.6-75%) (14 studies), arousal problem (7.9-89%) (16 studies), orgasmic dysfunction 4.5-77% (26 studies), lack of lubrication (5.6-51.5%) (20 studies), dissatisfaction with sexual life (6.7-52.5%) (9 studies), dyspareunia (4-23%) (7 studies) and decreased genital sensation (17.6-61.7%) (12 studies). Percentage of patients reporting primary SD was 43-83.3% (4 studies), secondary SD was 37.5-56.8% (3 studies) and tertiary SD  29.5-33.3% (2 studies). 
Clinical parameters found to be associated with SD were advancing age, lower educational level, longer length of marriage, longer disease duration, progressive MS, greater neurological disability (EDSS score), the presence of depression and anxiety, fatigue, poor mental health and poor quality of life. 
Studies showed beneficial effects of non-pharmacological interventions such as sexual therapy (1 per week x 12 week, RCT), sexual counselling (one 90-min session per week x 4 weeks, RCT), psychoeducation and sexual counselling (3 visit over 6 months, RCT), mindfulness, psychoeducation and cognitive behavioral therapy (90 minute sessions x 5 weeks,  pre/post study), pelvic floor muscle training and/or electrical stimulation and yoga training on sexual function.
Only two studies reported the effects of pharmacological interventions.  Use of sildenafil resulted in improvement in vaginal lubrication (RCT) and improvement of urinary incontinence after intradetrusor injections of botulinum toxin were associated with beneficial effects in sexual functions. Quality of evidence in all studies was weak.

There is a substantial variability in reported sexual dysfunction based on different methods to determine SD and lack of information on sampling method. The most commonly reported patterns of SD in women with MS were problems with desire, arousal, and orgasm. Clinical parameters were found to contribute to SD. There are some studies to determine the efficacy of interventions for SD but these were mainly observational.

Sexual dysfunction is highly prevalent in women with MS and different domains of sexual functions are affected.  Well designed studies evaluating practical strategies and pharmacological interventions are lacking.