Aims: To evaluate the efficacies of the estrogen receptor-alpha (ER-alpha) gene polymorphisms and of the intrafollicular insulin-like growth factor (IGF) system for predicting pregnancy in in vitro fertilization and embryo transfer (IVF-ET) patients.
Methods: A total of 96 patients undergoing IVF-ET were included in this study. Genotyping for the ER-alpha gene PvuII and XbaI polymorphisms was performed using polymerase-chain reaction and single base extension method. Follicular fluid (FF) IGF-I, IGF-II, and IGFBP-3 concentrations were measured by RIA, and IGFBP-4 by ELISA. We compared, between pregnant (n = 28) and non-pregnant groups (n = 68), the allele frequency, genotype distribution and haplotype distribution of PvuII and XbaI polymorphisms, and then FF IGF-I, IGF-II, IGFBP-3, IGFBP-4 concentrations and their ratios.
Results: No significant differences were found between the two groups in terms of allele, genotype or haplotype distributions of the ER-alpha gene PvuII and XbaI polymorphisms between the two groups. The mean FF IGF-I/IGFBP-3 ratio was significantly higher in the pregnant group (5.9 +/- 1.5 vs. 4.8 +/- 1.5 x 10(-2)).
Conclusions: The intrafollicular IGF-I/IGFBP-3 ratio of the FF of the dominant follicle during oocyte retrieval appears to be related to the establishment of pregnancy in IVF-ET patients, whereas the ER-alpha gene PvuII and XbaI polymorphisms do not.