Objectives: To measure serum resistin levels in infertile women undergoing in vitro fertilisation-embryo transfer (IVF-ET), and to find any correlations between serum resistin levels and body weight, body mass index, the number of oocytes retrieved, and the outcome of IVF-ET. In addition, to assess whether there is any difference in serum resistin levels between infertility caused by polycystic ovary syndrome (PCOS) and infertility caused by other female factors.
Methods: We designed a case-control study, and a total of 44 infertile women were enrolled. The blood samples for resistin measurement were collected on day 3 of the menstrual cycle prior to the administration of gonadotropin during in vitro fertilisation. These cases were then divided into 2 subgroups (PCOS group versus non-PCOS group) and a number of variables were measured and compared, including serum resistin levels.
Results: Serum resistin levels were inversely correlated with the number of oocytes retrieved (r=-0.371, p=0.013). No significant correlation was found between serum resistin levels and body mass index or body weight, either in the whole group or in the 2 subgroups. Serum resistin levels in the non-PCOS group were significantly higher than in the PCOS group (p=0.049). Serum resistin levels in the non-PCOS group were inversely correlated to the number of oocytes retrieved (r=-0.386, p=0.039), but no similar correlation was found in the PCOS group. There was no correlation between serum resistin levels and fertility rate or clinical pregnancy rate in either subgroup.
Conclusions: We observed a negative correlation between serum resistin levels and the number of oocytes retrieved during IVF. However, this phenomenon was only present in the non-PCOS group. This result suggests that serum resistin levels might be a good predictor of ovarian response in infertile women without PCOS during IVF. The role of serum resistin in response to inflammation caused by endometriosis or chronic pelvic infection, both of which are major causes of female infertility, should be examined in a further study.