Effect of endometrial thickness on pregnancy outcome in intrauterine insemination: a retrospective study

Abstract

Background: Intrauterine insemination (IUI) is a management option for infertility. We aimed to investigate the association between endometrial thickness (ET) and pregnancy outcome after IUI, and to identify factors affecting outcome in a Hong Kong population.
Methods: Medical records of women who underwent IUI at the infertility clinic of Queen Elizabeth Hospital from January 2013 to June 2019 were reviewed. Only the first cycle was included in the analysis to avoid over-representation of patients who failed treatment. Patients with or without clinical pregnancy were compared, as were patients with or without ongoing pregnancy. The predictive power of ET for pregnancy in IUI was assessed using the area under the receiver operating characteristic curve. Proportions of clinical pregnancy and ongoing pregnancy were calculated for 3 different subgroups of ET (<7 mm, 7-10 mm, and >10 mm).
Results: Of 337 IUI cycles, the clinical pregnancy rate was 12.7% (n=43); the ongoing pregnancy rate was 10.6% (n=36); and the multiple pregnancy rate was 1.4% (n=5). Shorter duration of infertility was associated with clinical pregnancy (2.67 years vs 3.51 years, p=0.003) and ongoing pregnancy (2.64 years vs 3.50 years, p=0.001). ET was not predictive of clinical pregnancy or ongoing pregnancy, with the area under the receiver operating characteristics curve being 0.473 and 0.509, respectively. Highest clinical and ongoing pregnancy rates occurred in those with ET
of >10 mm. In patients with ET of >10 mm, all patients with clinical pregnancy successfully carried on to ongoing pregnancy.
Conclusion: ET is not predictive of IUI success. Longer duration of infertility adversely affects IUI outcome.