Prognosis in unexplained recurrent pregnancy loss: a systematic review and quality assessment of current clinical prediction models

Objective: To identify models predicting live birth or ongoing pregnancy in couples with unexplained recurrent pregnancy loss (RPL) and evaluate the risk of bias, performance, generalizability, and applicability of these models. Evidence Review: A systematic literature search was performed in PubMed, Embase, Web of Science, and Cochrane Library until December 2020. Studies were eligible for inclusion if they were original studies predicting pregnancy outcome in patients with unexplained RPL and presented a tool that allowed for individual predictions. The risk of bias and applicability of the studies were assessed using the Prediction model Risk of Bias Assessment Tool. The Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis statement was used to assess reporting quality. Results: The search yielded 1,170 unique articles that were screened on the basis of the title and abstract. Seven studies were included: 1 prospective cohort study and 6 retrospective cohort studies. The recommended steps for the development of a prediction model were not followed by any of the studies, although 6 were published before the Prediction model Risk of Bias Assessment Tool and Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis guidelines. The included studies had a high risk of bias and were not externally validated. Conclusion: International guidelines recommend supportive care programs with prognostic counseling for couples with unexplained RPL. This information manages the expectations of couples and improves their ability to make an informed decision regarding further pregnancy attempts. On the basis of the results of this study, we cannot recommend the use of any of the studied prediction models in clinical practice to prevent overestimation of chances and false belief.