Association between serum and follicular fluid vitamin D levels and pregnancy rate in women undergoing in vitro fertilization/intracytoplasmic sperm injection

Introduction: There are controversies about relationship between serum and follicle vitamin D levels and in vitro fertilization (IVF) outcomes. Objectives: The goal of this study was to determine association between serum and follicular vitamin D levels and IVF outcome in the Iranian population. Patients and Methods: This cohort study was conducted in a women’s hospital. One hundred and sixty patients (mean age = 28 years ) who were candidates (by simple sampling) for IVF enrolled in the study. Levels of 25 (OH)-D in follicular fluid and serum were measured. Biochemical pregnancy was determined by detecting serum β-hCG. A detectable gestational sac was considered as a characteristic of clinical pregnancy. Results: Biochemical pregnancy was detected in 49 (30.6) and clinical pregnancy in 39 (24.4). Mean vitamin D levels of serum and follicular fluid were not significantly different between cases that had clinical pregnancy or not. In cases with serum vitamin D level less than 30, mean follicular vitamin D level and body mass index (BMI) were significantly lower than the cases with serum vitamin D level more than 30. Mean serum vitamin D levels, biochemical and clinical pregnancy rates were significantly different in cases with follicular vitamin D level less or equal/more than 30. Logistic regression by considering biochemical pregnancy as dependent variable and other variables as independent variables showed that the only independent predictor was grade of embryo Conclusion: Follicular vitamin D level could affect pregnancy outcome in IVF cycles while serum vitamin D levels do not play any role in the IVF outcome.