A nomogram predicting clinical pregnancy in the first fresh embryo transfer for women undergoing in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) treatments

The extent to which factors affect the probability of clinical pregnancy in the first fresh embryo transfer after assisted conception is unknown. In order to examine the predictors of clinical pregnancy, a retrospective cohort study was launched between January 1, 2013 and December 31, 2016 in four infertility clinics including 19 837 in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) fresh cycles with known outcomes and relevant records. A multivariable logistic regression was used to select the most significant predictors in the final nomogram for predicting clinical pregnancy. Furthermore, the model was validated by an independent validation set and the performance of the model was evaluated by the receiver operating characteristic (ROC) curves along with the area under the ROC curve (AUC) and calibration plots. In a training set including 17 854 participants, we identified that female age, tubal factor, number of embryos transferred, endometrial thickness and number of good-quality embryos were independent predictors for clinical pregnancy. We developed a nomogram using these five factors and the predictive ability was 0.66 for AUC (95% CI 0.64-0.68), which was independently validated in the validation set (AUC=0.66, 95% CI 0.65-0.68). Our results show that some specific factors can be used to provide infertile couples with an accurate assessment of clinical pregnancy following assisted conception and facilitate to guide couples and clinicians.