Relation of serum vitamin D level in polycystic ovarian syndrome (PCOS) patients to ICSI outcome

Background Recently, vitamin D was discovered to have an important role in female reproduction and IVF. However, there were no studies specifically addressed its role in polycystic ovarian syndrome (PCOS) patients undergoing ICSI cycles. Therefore, this cross-sectional study in a university hospital was conducted to evaluate the effect of serum level of vitamin D (VD) on the number of retrieved and fertilized oocytes, and chemical and clinical pregnancy rate in PCOS females undergoing ICSI cycles. The study included 80 PCOS cases undergoing ICSI cycles in the age from 20 to 39 years using antagonist protocol. Cases with severe male or tubal factors were excluded. Serum 25 (OH) D vitamin level was assessed by the ELIZA method on the day of oocyte retrieval. Correlation and regression analyses were used in the analysis. Results VD was positively correlated to both numbers of retrieved and fertilized oocytes ( r = 0.35, 95% CI 0.15, 0.53, P = 0.001; r = 0.33; 95% CI 0.03, 0.57, P = 0.03, respectively). It was still significantly correlated to the number of oocytes (coefficient 0.47; 95% CI 0.1, 0.9; P = 0.018) and to the number of fertilized eggs (coefficient 0.3; 95% CI 0.02, 0.58; P = 0.03) after adjusting for age, BMI, and type of ovulation-triggering agent. This means with each 2 ng/mL increase in serum VD level, around one more egg will be retrieved. In addition, there will be one more fertilized oocyte with each 3 ng/mL increase in the vitamin level. However, no significant correlation was found between the vitamin level and the occurrence of chemical or clinical pregnancy. Conclusions Serum vitamin D level is positively correlated with the number of retrieved and fertilized oocytes in PCOS patients undergoing ICSI cycles.