Serum and FF levels of 25 OH vitamin D were highly correlated (r=0.94, p<0.001, ) demonstrating that FF levels of 25OH-D indeed were reliable reflectors of body stores of the vitamin. As per serum level criteria (5
), only 37% of participants demonstrated replete 25OH-D stores (>30ng/ml); 36% met criteria for insufficiency (20–30ng/ml) whereas 27% were vitamin D deficient (<20ng/ml) ().
Follicular fluid 25-OH Vitamin D reliably reflects serum levels
Population prevalence (%) of Vitamin D status
In a predominantly Caucasian population (66%), significantly lower FF 25OH-D levels were noted in Blacks (n=12) compared to patients of non Black ethnicity (n=64) (18.88 ± 8.5ng/ml versus 30.51± 12.95 ng/ml, p=0.001). Significant inverse correlations were noted between FF 25OH-D levels and BMI (r=−0.25, p=0.035). Although lower FF 25OHD levels were noted in eight patients with polycystic ovarian syndrome (PCOS) and in twenty women with diminished ovarian reserve (DOR) compared to those with other infertility etiologies (26.19±11.22 in PCOS versus 28.57±13.09 ng/ml in non-PCOS patients and 24.16 ± 9.57 in DOR versus 29.65±13.5 ng/ml in patients with normal ovarian reserve), these differences were not of statistical significance (p>0.05).
describes the participant and IVF cycle characteristics by outcome of IVF cycle (i.e. CP versus not pregnant). Those achieving CP (n=26, 30.95%) demonstrated significantly higher FF 25OH-D compared to those with unsuccessful cycles (n=58, 69.04 %, p=0.013, ), utilized significantly lesser doses of gonadotropin ampoules for shorter duration (in days) and were transferred significantly higher number of embryos compared to those whose IVF cycles were unsuccessful; the remaining IVF cycle characteristics did not differ significantly () and the proportions of cycles utilizing GnRH agonist versus antagonist were similarly comparable across the two groups (in those achieving CP, 55% of cycles utilized GnRH agonist compared to 53% in those with failed outcome, p=0.857).
Participant and IVF cycle characteristics by outcome of IVF cycle
Significantly higher follicular fluid 25OH Vitamin D levels are noted in IVF cycles achieving clinical pregnancy
While significant differences were observed in cycle parameters in patients achieving CP and those with failed outcomes as specified in , no direct relationship was observed between patient and cycle parameters and 25OH-D levels, i.e. there was no correlation observed between FF 25OH-D levels and ovarian response parameters (i.e. duration of COH, number of follicles, number of eggs retrieved, maximal estradiol) nor with ovarian reserve parameters (age or FSH) (data not shown). Although a trend towards increasing ovarian response (shorter duration of COH, increasing estradiol levels) was observed across tertiles for vitamin D, these differences were not statistically significant (p>0.05, data not shown).
Significant increase in implantation and CP rates was observed across tertiles of 25OH D distribution (, p=0.041 and 0.029 respectively); all other patient and cycle parameters were comparable across tertiles of 25OH D including patient age, BMI, FSH, dose of gonadotropins, duration of COH, maximal estradiol, number of eggs retrieved and number of embryos transferred (data not shown). Those in the highest tertile for 25OH D were almost four times more likely to achieve CP compared to patients in the lowest tertile (OR for CP 3.83, 95% CI 1.20–12.28, p=0.024).
Increasing implantation and clinical pregnancy rates are observed across FF 25OHD tertiles.
Multivariable logistic regression incorporating propensity score analyses confirmed FF 25OH-D levels as an independent predictor of success of an IVF cycle; adjusting for age, BMI, ethnicity and number of embryos transferred, each ng/ml increase in FF 25OH-D level enhanced the likelihood for achieving CP by 6% (p=0.030, ). Alternatively, those with FF 25OHD levels in the lowest to mid tertiles were 75% less likely to achieve CP compared to women with FF Vitamin D levels in the highest tertile (OR for CP 0.25, 95% CI 0.07–0.84, p=0.026).
Predictors of successful clinical pregnancy following IVF (associations presented as odds ratio ± 95% Confidence intervals)
Of the 84 IVF cycles, 81 were first ART cycles whereas 3 were repeat cycles. Sensitivity analyses were conducted excluding the 3 repeat ART cycles and confirmed essentially unchanged magnitudes of association, (OR’s, CI’s and p values) in the previously observed relationships between 25OHD and IVF cycle outcome (data not shown).