Association between Vascular Endothelial Growth Factor and Clinical Outcomes of IVF-ET/ICSI

To investigate the association between the level of vascular endothelial growth factor (VEGF) and the quality of early embryos as well as clinical outcome after embryo transplantation in embryo culture medium of patients treated with IVF-ET/ICSI, and explore the association between VEGF 936 C/T gene polymorphisms and IVF-ET/ICSI clinical outcomes.

Case-control study.

The Reproductive Medical Center, Yantaishan Hospital, Yantai, Shandong Province, China, from January to December 2016.

Ninety-eight patients undergoing IVF-ET/ICSI treatment were divided into pregnant group (n=58) and nonpregnant group (n=40), based on clinical outcomes. Average age, infertility duration, body mass index, number of previous grafts, basic follicle-stimulating hormone (FSH) levels, luteinizing hormone (LH) levels, chorionic gonadotropin (HCG) intimal thickness, estrogen (E2) levels, progesterone (P) levels, and other relevant indicators were compared between the two groups. The vascular endothelial growth factor (VEGF) levels in the embryo culture medium were detected by enzyme-linked immunosorbent assay (ELISA). Meanwhile, VEGF 936 C/T genotype and allele frequency (%) were compared between the two groups.

There was no significant difference in average age, infertility duration, number of previous grafts, basic folliclestimulating hormone (FSH) levels, luteinizing hormone (LH) levels, chorionic gonadotropin (HCG) intimal thickness, estrogen (E2) level, progesterone (P) level, number of retrieved oocytes, embryo number, quality embryo number, quality embryo rate, and cumulative embryo score (CES) of transplanted embryo between the two groups (P=0.601, 0.180, 0.741, 0.119, 0.693, 0.282, 0.064, 0.505, 0.712, 0.822, 0.663, 0.150, 0.178, 0.204 and 0.263, respectively). VEGF level in embryo culture medium was lower in pregnant group than non-pregnant group, with statistically significant difference (p<0.001). VEGF level in the culture medium of grade I embryos was significantly lower than that of grade II embryos (p<0.001). The frequencies of CC genotype and C allele in VEGF 936 in the non-pregnant group were higher than those in the pregnant group (p=0.003, and 0.005, respectively).

VEGF level in the embryo culture medium can be used as one reference indicator for predicting embryo quality and pregnancy outcome. The VEGF 936 C/T gene polymorphism may be related to IVF-ET/ICSI treatment outcome, and C allele may be a susceptibility gene for IVF-ET/ICSI failure.