Objective: To validate four pretreatment prediction models which were developed based on UK/US population (McLernon 2016 model, Luke model, Dhillon model, and McLernon 2022 model) and compare them with a model developed based on local data. Design: Retrospective development and validation of prediction models. Setting: University-affiliated hospital Patient(s): A total of 26035 Chinese patients underwent OPU cycles between January 2013 and December 2020. Methods: UK/US model performance was externally validated. Local models were established with XGboost, Lasso, and generalized linear model algorithms. Discriminatory power and calibration of the models were compared. Main Outcome Measure(s): The areas under the curves (AUC) of the Receiver Operator Characteristic (ROC) and calibration curves. Result(s): The AUCs for McLernon 2016 model, Luke model, Dhillon model, and McLernon 2022 model were 0.68 (95% CI: 0.675-0.689), 0.67 (95% CI: 0.666-0.68), 0.685((95% CI: 0.678-0.692), and 0.673((95% CI: 0.666-0.68), respectively. The local model yielded an AUC of 0.709(95% CI: 0.702-0.716) with key predictors including age, duration of infertility, and endocrine parameters. All external models suggested underestimation. Among the external models, the rescaled McLernon 2022 model demonstrated the best calibration (slope 1.12, intercept 0.06). Conclusion(s): A patient in China may find the published pretreatment prediction models based on UK/US population provide similar discriminatory power with reasonable AUCs and underestimated predictions.

Abstract Objective: To evaluate the association between body mass index (BMI) and pregnancy outcomes in women receiving intrauterine insemination (IUI) treatment． Design: Retrospective cohort study. Setting: University-affiliated hospital. Population: Six thousand four hundred and seven women undergoing 13,745 IUI cycles stratified by body mass index (BMI). Method: Cox regression was used to analyze the association between BMI and cumulative live birth across multiple IUI cycles. GEE was used to analyze the live birth rate per cycle. Main Outcome Measure(s): Cumulative outcomes for IUI cycles. Result(s): Compared with normal weight women (n = 4,563), underweight women (n = 990) had a lower cumulative pregnancy and live birth rate (20.71% vs 25.93%, 17.07% vs 21.61%, respectively), while overweight women (n = 854) had a higher cumulative pregnancy and live birth rate (31.97%, 26.58%). Adjusted for confounders, hazard Ratio (HR) for achieving live birth following up to a maximal of 4 IUI cycles was 0.8(95%CI: 0.67-0.95) comparing underweight with normal weight. In generalized estimating equation (GEE) analyses, low BMI was also associated with a lower per-cycle live birth rate 0.77(95%CI: 0.64-0.92) with adjustment for cycle-specific parameters, including ovarian stimulation, endometrial thickness and follicular diameter. Conclusion(s): Underweight is associated with poor IUI outcomes. Funding: Clinical Research Special Fund of Chinese Medical Association (NO.18010360765) and Xiamen Medical Advantage Subspecialty Construction Project (2018[296])

Objective: To evaluate the effect of transferring a poor quality embryo (PQE) with a good quality embryo (GQE) on the outcomes in poor prognosis patients. Design: Retrospective cohort study. Setting: University-affiliated hospital. Population: A total of 5,037 FBT cycles between January 2012 and May 2019. Methods: Single FBT with GQE were defined as group G and double FBT with GQE plus PQE were defined as group GP. Propensity score matching was applied to control for potential confounders. Multivariate generalized estimating equations (GEE) models were used to identify the association between the effect of an additional PQE and outcomes. Main Outcome Measures: Live births and multiple pregnancies. Results: Group GP resulted in a significantly higher live birth rate (LBR) than group G in women aged 35 and over and in women who received over 3 cycles of embryo transfer (ET) (48.1% vs 27.2%, OR:2.56, 95% CI: 1.3-5.03 and 46.6% vs 35.4%, OR:1.6, 95% CI: 1.09-2.35), while LBR were statistically similar between two groups in women under 35 and in women who received less than 3 cycles of ET (48.7% vs 43.9%, OR:1.22, 95% CI: 0.93-1.59 and 48.3% vs 41.4%, OR:1.33, 95% CI: 0.96-1.85). Notably, group GP were found a consistent significantly higher multiple pregnancy rate than group G. Conclusions: The transfer of an additional PQE with a GQE increases live births in poor prognosis patients. Funding：None. Keywords: poor quality embryo, good quality embryo, LBR, poor prognosis patients