Comparison Of The Correlation Between Free And Total 25(OH)D With Fertility Parameters In IVF-ET Females

ObjectiveVitamin D plays an important role in reproduction.Before,the levels of vitamin D had been mainly measured by total 25-hydroxyvitamin D?25?OH?D?.But,free25?OH?D has more advantageous than total 25?OH?D in reflecting vitamin D level and predicting disease.However,the relationship between free 25?OH?D and female fertility parameters has not been reported.Therefore,Therefore,this study aims to compare the correlation of free and total 25?OH?D with fertility parameters in in vitro fertilization and embryo transfer?IVF-ET?females,so as to clarify the clinical significance of free 25?OH?D further.MethodsAccording to the inclusion and exclusion criteria,infertility patients who performed IVF-ET for the first time in a hospital at Changsha from January 2017 to December 2018 was recruited and provided the informed consent form.5ml venous blood was collected on the day before embryo transfer?ET?.After centrifugation,the upper serum was taken and stored at-80?.Enzyme linked immunosorbent assay?ELISA?kits was used to detect total 25?OH?D and free 25?OH?D.Clinical information was collected.Finally,the statistical analysis was performed using SPSS20.0 statistical software.P<0.05 was considered as the difference was statistically significant.Results1.According to the inclusion and exclusion criteria,2569 women who received IVF-ET treatment for the first time participated in this study.2.Distribution and correlation of free and total 25?OH?D of the study population on the day before ET:The distribution of free and total 25?OH?D on the day before ET was abnormality?P<0.05?.The median?IQR?of free 25?OH?D was 4.71?4.11-5.31?pg/mL and total 25?OH?D was 19.54?16.52-22.83?ng/mL.The correlation between free25?OH?D and total 25?OH?D was significantly positive?P<0.001?.3.Analysis and comparison of the correlation between free and total 25?OH?D with fertility parameters in IVF-ET females:Free 25?OH?D was significantly positive with basal follicle-stimulating hormone?FSH?,basal estradiol?E₂?,progesterone?P?/E₂ on human chorionic gonadotropin?hCG?trigger day and P/E2 on the day before ET,and was significantly negative with anti-Müllerian hormone?AMH?,antral follicle count?AFC?,E₂ on hCG trigger day,number of oocytes retrieval,E₂ on the day before ET and P on the day before ET?P<0.05?.Total 25?OH?D was significantly and positively correlated with age and basic E₂,luteinizing hormone?LH?on hCG trigger day,E₂ on hCG trigger day and E2 on the day before ET,and significantly and negatively correlated with basal FSH/LH,number of days of ovarian stimulation,gonadotropin?Gn?dosage,hCG dosage,P/E₂ on the day before ET and endometrial thickness on the day before ET?P<0.05?.Compared to total 25?OH?D,free 25?OH?D was more correlated with basal FSH,basal E₂,AMH,AFC,E₂ on h CG trigger day,P/E₂ on hCG trigger day,number of oocytes retrieval,E2 on the day before ET,P on the day before ET,and P/E2 on the day before ET.4.Analysis and comparison of the correlation between free and total 25?OH?D with fertility parameters in IVF-ET females by multiple linear regression:The results of multiple linear regression analysis showed there significantly was a positive correlation of free 25?OH?D with basal E2,Gn dosage,hCG dosage,P/E2 on hCG trigger day,P/E2on the day before ET,and a negative correlation of AMH,AFC,E2 on hCG trigger day,number of oocytes retrieval,E₂ on the day before ET,and P on the day before ET?P<0.05?.The results of multiple linear regression analysis showed total 25?OH?D was significantly and positively correlated with age,LH on hCG trigger day,E₂ on hCG trigger day,and E2 on the day before ET,and was significantly and negatively correlated with number of days of ovarian stimulation,Gn dosage,hCG dosage,P/E2 on hCG trigger day,P/E₂ on the day before ET and endometrial thickness on the day before ET?P<0.05?.Compared to total 25?OH?D,free 25?OH?D was higher correlation with the basal E₂,AMH,AFC,Gn dosage,hCG dosage,E₂ on hCG trigger day,P/E₂ on hCG trigger day,number of oocytes retrieval,E2 on the day before ET,P on the day before ET and P/E2 on the day before ET.Conclusions1.Serum free 25?OH?D was significantly correlated with serum total 25?OH?D in IVF-ET females.2.Free 25?OH?D was significantly and positively correlated with basal E2,P/E2 on hCG trigger day,and P/E₂ on the day before ET,and significantly negatively correlated with AMH,AFC,E2 on hCG trigger day,number of oocytes retrieval,E2 on the day before ET and P on the day before ET.3.Total 25?OH?D was significantly and positively correlated with age,LH on hCG trigger day,E2 on hCG trigger day,and E2 on the day before ET,and significantly negatively correlated with number of days of ovarian stimulation,gonadotropin?Gn?dosage,hCG dosage,E2 on the day before ET and endometrial thickness on the day before ET.4.Compared to total 25?OH?D,free 25?OH?D was higher correlation with fertility parameter,including basal E2,AMH,AFC,E2 on hCG trigger day,P/E2 on hCG trigger day,number of oocytes retrieval,E₂ on the day before ET,P on the day before ET and P/E2 on the day before ET.