The effect of unilateral tubal block diagnosed by hysterosalpingogram on clinical pregnancy rate in intrauterine insemination cycles: systematic review and meta-analysis

Background Fallopian tube occlusion is a common cause of infertility, but the effect of unilateral tubal block (UTB) on pregnancy rates (PR) after controlled ovarian hyperstimulation and intrauterine insemination (COH-IUI) remains controversial. Objective To evaluate PR after COH-IUI among infertile women with proximal and distal UTB diagnosed by hysterosalpingogram (HSG), compared against women with bilateral patent tubes experiencing unexplained infertility. Search strategy We searched EMBASE, MEDLINE, Google Scholar, Cochrane Library, and PUBMED from inception to 14 January 2018. Selection criteria Studies that report PR/cycle or cumulative PR among women with UTB and controls were included. Data collection and analysis Two authors independently selected and extracted study characteristics and data. Methodological quality was assessed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Main results Among 2965 patients and 5749 IUI cycles across ten studies, no significant difference in PR/cycle (odds ratio, OR = 0.88; 95% confidence interval, 95% CI = 0.69-1.12) and cumulative PR (OR = 0.80, 95% CI = 0.62-1.04) was observed. Patients with proximal UTB demonstrated similar PR/cycle (OR = 1.06, 95% CI = 0.68-1.66) and cumulative PR (OR = 1.10, 95% CI = 0.75-1.62), compared with controls, whereas patients with distal UTB had significantly lower cumulative PR (OR = 0.49, 95% CI = 0.25-0.97, P = 0.04). Patients with proximal block also demonstrated significantly improved cumulative PR, compared with patients with distal block (OR=2.41, 95% CI = 1.37-4.25, P = 0.002). Conclusion Infertile patients with proximal UTB diagnosed by HSG can expect similar pregnancy rates after COH-IUI, compared with those with bilateral tubal patency and unexplained infertility, whereas patients with distal UTB have lower odds of pregnancy. These differences may reflect inherent diagnostic limitations of HSG or differences in underlying pathologies.