Investigating the rate of different ovarian response in in vitro fertilization cycles based on estrogen receptor beta +1730 polymorphism: A cross-sectional study

Background: The response to ovarian stimulation is different among women referring for assisted reproductive techniques. This difference could be due to different genotypes in genes related to reproduction such as estrogen receptor beta (ER𝛽 or ESR2) gene. Objective: In the present study, we explored the rate of ESR2 gene polymorphism in infertile women undergoing IVF treatment with different ovarian response to ovulation induction. Materials and Methods: A cross-sectional study was performed among 91 infertile women. The relationship between genotype distribution of the +1730 G/A polymorphism in the ESR2 gene (rs4986938) and the mean number of follicles and oocytes, their mean ratio, mean number of embryos, mean size of the follicles and pregnancy rates were measured. The ESR2 gene +1730 G/A polymorphism were identified by the amplification-refractory mutation system-polymerase chain reaction. Results: Genotypes GG, GA, and AA of the ESR2 gene presented frequencies of 27.5%, 67%, and 5.5%, respectively, in the infertile women. The results of the study showed that the mean number of follicles and oocytes, their mean ratio, mean number of embryos, mean size of the follicles, and pregnancy rates are not related to different genotypes. Conclusion: According to the endocrine and paracrine factors which are involved in the ovulation induction and maturation of oocytes, more studies with higher number of participants are required to confirm the results of the present study; in addition, further studies are required to find out other gene polymorphisms affecting estrogen receptor efficacy in the infertile women.