Factors predicting clinical pregnancy rate of in vitro fertilization-embryo transfer (a STROBE-compliant article)

The aim of this study was to investigate the factors predicting clinical pregnancy rate of in vitro fertilization-embryo transfer (IVF-ET).The data of 9960 patients receiving IVF-ET fresh cycle at our Reproductive Center from January 2009 to December 2017 were first divided into pregnant group and non-pregnant group to find the clinical pregnancy rate-related factors. According to the serum HCG levels at 36 hours and 12 hours after HCG trigger, all patients were divided into 4 groups including <50 mIU/ml, ≥50 and <100 mIU/ml, ≥100 and <200 mIU/ml, and ≥200 mIU/ml groups to know whether the HCG levels at 36 hours and 12 hours affect the pregnancy rate. According to the serum HCG ratio at 36 hours to 12 hours (36 h/12 h) after HCG trigger, all patients were divided into three groups including <0.88, 0.88-1.06 and >1.06 groups to observe whether the serum HCG ratio (36 h/12 h) affects the clinical pregnancy rate. According to different assisted pregnancy modes, all patients were divided into 3 groups including IVF, ICSI, and IVF/ICSI groups to observe whether the assisted pregnancy mode affects the clinical pregnancy rate. The correlation of the clinical pregnancy rate with pregnancy rate-related factors obtained above was analyzed using logistic regression analysis model.The clinical pregnancy rate significantly increased (P < .01) in the HCG ratio (36 h/12 h) >1.06 group as compared with the HCG ratio (36 h/12 h) < 0.88 and 0.88-1.06 groups. The serum estrogen (E2) level at 36 hours was significantly lower and the number of retrieved oocytes was significantly higher in the HCG ratio (36 h/12 h) >1.06 group than in the HCG ratio (36 h/12 h) <0.88 and 0.88-1.06 groups (P = .000).The serum HCG ratio (36 h/12 h) may be used as a predictor of IVF-ET clinical pregnancy rate. High clinical pregnancy rate is probably associated with E2 down-regulation in the HCG ratio (36 h/12 h) >1.06 group.