A retrospective cohort study: predictive nomogram for clinical pregnancy outcomes after intrauterine insemination.

INTRODUCTION

Intrauterine insemination (IUI) is a widely used assisted reproductive technique; however, the factors associated with clinical pregnancy remain incompletely understood. This study aimed to identify factors associated with clinical pregnancy and develop an exploratory prediction model for clinical pregnancy after IUI.

METHODS

In this retrospective cohort study, we analyzed clinical and laboratory data from 764 IUI cycles performed between January 2019 and December 2024. The data were divided into a training set (75%, 573 cycles) and a validation set (25%, 191 cycles) according to the treatment timing. Multivariable logistic regression analysis was performed to identify factors associated with clinical pregnancy, and a nomogram was developed based on the final model.

RESULTS

In the multivariable logistic regression analysis, female age [odds ratio (OR) = 0.938, 95% confidence interval (CI): 0.885-0.995, P = 0.034], body mass index (OR = 1.065, 95% CI: 1.014-1.118, P = 0.012), and anti-thyroid peroxidase antibodies (log-transformed, OR = 1.002, 95% CI: 1.000-1.004, P = 0.028) were significantly associated with clinical pregnancy. Controlled ovarian stimulation was also associated with clinical pregnancy (OR = 1.843, 95% CI: 1.296-2.623, P = 0.048). However, this association should be interpreted cautiously due to potential confounding by indication. Anti-Müllerian hormone was retained in the final model due to its established clinical relevance to ovarian reserve assessment, although it did not reach conventional statistical significance (P = 0.051). A nomogram incorporating these five variables was developed, achieving an area under the curve of 0.653 (95% CI: 0.608-0.697).

DISCUSSION: Given its limited discriminative performance, the model should be considered an exploratory tool rather than a definitive clinical decision-making tool. These findings may provide preliminary information for individualized counseling; however, external validation in larger, prospective, multicenter cohorts is required before clinical application.