Abstract: Objective：To clarify the relationship between the brain-derived neurotrophic factor (BDNF) with single nucleotide polymorphism (SNP, Val/Met) and the female infertility with endometriosis, as well as its effect on the pregnancy outcome of in vitro fertilization-embryo transfer (IVF-ET). Methods: A total of 112 cases with III-IV EMs undergoing IVF-ET from September 2015 to September 2016 were enrolled in the study group, and 109 infertile cases with tubal factors as the control group. The Val66Met polymorphism of BDNF gene was analyzed, and the difference in the pregnancy outcome of IVF-ET was compared between the two groups. Results: ①There were no significant differences in age, infertile years, body mass index (BMI), basal follicle stimulating hormone (FSH) and basal estradiol (E2) between the two groups (P＞0.05). ②The proportions of Met/Met genotypes and Met allele frequencies in the study group were significantly higher than those in the control group (33.0% vs. 23.9%, P=0.043; 58.9% vs. 47.7%, P=0.018). In both groups, the patients with Met/Met genotype had a higher Gn dose than those with the other 2 genotypes, while they had lower number of matured eggs (4.5±3.2 vs. 5.2±2.3) and fertilization rate (59.0% vs. 67.0%) (all P＜0.05). ③In both groups, the patients with Met/Met genotype had the decreased level of BDNF protein in follicular fluid when compared with those patients with the other 2 genotypes (P＜0.05). However, there was no significant difference in the level of plasm BNDF between menstrual period and hCG day (P＞0.05). Conclusions: The Val66Met polymorphism of BDNF gene is associated with the endometriosis-related infertility. Moreover, this SNP is also related with the poor IVF-ET outcomes in both endometriosis-related and tubal obstructed infertile women.

Key words: Brain-derived neurotrophic factor, Polymorphism, single nucleotide, Endometriosis, Fertilization in vitro, Embryo transfer, Fallopian tube diseases