Abstract: Objective  To investigate the relationship between the level of interleukin-1β(IL-1β) secreted by embryos in embryo culture medium and embryo development and implantation potential. 
Methods  Eighty patients with fresh cycle infertility who underwent the first intracytoplasmic sperm injection-embryo transfer(ICSI-ET) operation were selected. Embryos were cultured in vitro with single droplet single embryo. Embryo transfer was performed on the third day after oocyte retrieval and fertilization, and the number of transferred embryos was 2. The corresponding microdroplets of cleavage-stage culture fluid from fresh-cycle embryos were collected and the levels of IL-1β in their supernatants were measured by enzyme-linked immunosorbent assay.According to the implantation rate per cycle, the patients were divided into group A(43 cases, implantation rate was 0%), group B(27 cases, implantation rate was 50%), and group C(10 cases, implantation rate was 100%). The main clinical data of the three groups were compared with the relevant parameters of embryo laboratory, the level of IL-1β secreted in embryo transfer medium, and the cumulative score of embryo transfer morphology. The correlation between the level of IL-1β and the cumulative score of embryo transfer morphology was analyzed. 
Results  There were 37 clinical pregnancies in 80 patients, and the clinical pregnancy rate was 46.3%, including 27 singleton pregnancies and 10 twin pregnancies.There was no significant difference in the main clinical data and embryo laboratory parameters among three groups(P＞0.05). The level of IL-1β in the culture medium of embryo cleavage stage in group B was higher than that in group A, and that in group C was higher than that in group A and group B, the difference was statistically significant(P＜0.05). There was no significant difference in cumulative scores of morphology among the three groups(P＞0.05). The level of IL-1β was positively correlated with the cumulative score of embryo morphology(r=0.587, P＜0.05). 
Conclusion  Endogenous IL-1β secreted by embryos during embryo culture is closely related to embryo development and implantation, and its evaluation of embryos and study on early embryo intervention can provide reference significance. 

Key words: embryo transfer； embryo culture medium, embryo development, interleukin-1β