[Influencing factors analysis on live birth outcome of D3 cleavage stage frozen-thawed embryo after overnight culture and development of nomogram prediction model].

Objective: To analyze the factors affecting the live birth outcome of D3 cleavage stage frozen-thawed embryos after overnight culture, and establish a nomogram model to predict the live birth probability. Methods: The clinical data of assisted reproductive patients treated with D3 cleavage stage frozen-thawed embryo transfer in the First Affiliated Hospital of Zhengzhou University from January 2017 to July 2020 were analyzed retrospectively. A total of 5 456 patients were divided into modeling group and validation group according to the ratio of 7∶3. The modeling group [3 831 patients with average age of (33±6) years] was used to evaluate the independent risk factors of the patient's live birth outcome through multivariate logistic regression analysis and construct the nomogram prediction model. The validation group [1 625 patients with average age of (33±6) years] was used to verify and calibrate the performance of the model. Results: The results of multivariate logistic regression analysis showed that the risk factors related to live birth outcome of D3 frozen-thawed embryos after overnight culture included: female age (OR=0.901,95%CI:0.889-0.914,P<0.001), body mass index (BMI) (OR=0.979,95%CI:0.957-1.002,P=0.072), endometrial thickness on the transfer day (OR=1.121,95%CI:1.080-1.164,P<0.001), the number of transferred embryos (OR=2.192,95%CI:1.867-2.579,P<0.001) and embryo division resumed after overnight culture (OR=1.405,95%CI:1.213-1.627,P<0.001). The area under the curve (AUC) of the nomogram model in the modeling group was 0.716 and that in the validation group was 0.739.Both sets of calibration curves fited well with the ideal curve, which illustrated that the model had good predictive ability. Conclusions: The female age, BMI endometrial thickness on the transfer day, the number of transferred embryos and the embryo division resumed after overnight culture are risk factors for the live birth outcome of frozen-thawed embryos after overnight culture. The nomogram established based on the above factors can help predict the probability of live birth after frozen-thawed embryo transfer.