Vitamin D in human reproduction: some answers and many more questions

We are in the midst of what has been deemed a worldwide vitamin D deficiency epidemic. Vitamin is secosteroid and its metabolites play major role regulation calcium phosphate homeostasis. Although well known to contribute bone growth remodeling, it implemented other imperative processes such as cell division, neuromuscular immune function, inflammation reduction. Its involvement reproductive physiology topic currently undergoing much research. Many women using infertility treatment assisted reproduction opt supplement with D, but whether repletion ultimately improves outcomes remains unclear. Ozkan et al. (1Ozkan S. Jindal Greenseid K. Shu J. Zeitlian G. Hickmon C. al.Replete stores predict success following vitro fertilization.Fertil Steril. 2010; 94: 1314Abstract Full Text PDF PubMed Scopus (224) Google Scholar) was one first groups look at technology (ART) respect status investigate replete predicted clinical pregnancy after fertilization (IVF). They found that serum follicular fluid 25(OH)D levels were highly correlated, patients who achieved had significantly higher levels. Rudick (2Rudick B. Ingles S.A. Chung Stanczyk Paulson R.J. Bendikson K.A. Influence on donor-recipient cycles.Fertil 2014; 101: 447-452Abstract (99) used IVF cycles further delineate D’s impact oocyte vs. endometrium, recipients nonreplete lower rates. These findings contrast Franasiak (3Franasiak J.M. Molinaro T.A. Dubell E.K. Scott K.L. Ruiz A.R. Forman E.J. al.Vitamin do not affect transfer euploid blastocysts.Am J Obstet Gynecol. 2015; 212: 315.e1-315.e6Abstract (66) demonstrated unrelated setting an optimized endometrium controlling for embryo endometrial synchrony. Measurement did likelihood implantation frozen transfers. In recent publication by Cai (4Cai Li Zeng Hu L. Peng Y. Tang al.Impact human - prospective cohort study fresh transfer.Fertil 2021; 115: 655-664Abstract (4) Scholar), similarly they unable demonstrate significant association between status. An examination methods assessment comparison differences cycle characteristics among these studies may help explain discrepant literature. One sets apart from available literature their approach measurement free addition total 25(OH)D. Current recommendations based assays measure This includes bound binding protein (VDBP) (approximately 85%–90%), albumin (10%–15%), unbound (<1%). be better indicator than 25(OH)D, this likely dependent end organ where acting population which being measured. Genotypic VDBP exist result varying concentrations fluctuations due comorbidities even estrogen Different polymorphisms differing affinities affects amount evaluated ART population. The correlated important our understanding unique majority laboratories use automated immunoassays unfortunately have many intrinsic analytic issues. Immunoassays very selective properly must 25(OH)D2 25(OH)D3 equimolar fashion without detecting similar metabolites. Additionally, previously discussed, circulates albumin, released prior measurement. cannot strong solvents release proteins making efficient dissociation difficult. also subject interference measurements, example, heterophilic antibodies, can lead either positive or negative interference. Liquid chromatography-mass spectrometry (LC-MS/MS) gold standard levels, however, LC-MS/MS requires expensive equipment trained staff. Also, less sample variation within compared immunoassay-based testing, some disparities still exist. shortcomings assay-based testing why others presented results. immunoassay via enzyme-linked immunosorbent assay. Furthermore, samples drawn day before kept -80°C until Recently, Lara-Molina (5Lara-Molina E.E. Devesa-Peiro A. Lopez-Nogueroles M. Florensa Martin al.The degradation across time: issue leading unreliable results research.Fertil 2019; 112: E339-E340Abstract degrades stored time. Samples quantified baseline 7 months storage storage. specify how long processing, possible degraded over Only small minority included classified having adequate If time lengthy, phenomenon could measured low throughout most When interpreting data collected infertile ART, prudent take into consideration cycles. investigated During process embryos placed back uterus while estradiol remain high. Supraphysiologic bioavailability influences concentrations. Therefore, difficult ascertain if applicable tend lower. different during earlier course stimulation. only drew transfer, determined level impactful regard quality resultant competency. nature transfers precludes preimplantation genetic aneuploidy. There emerging associated shown correlate telomere length cumulus cells mature follicles. perform aneuploidy and, therefore, ploidy transferred unknown, provide (good fair) quintiles aspect limits generalizability homogeneity studied. Not all same ethnicity, young, thin, good responders relatively prognoses. vast inadequate insufficient according predetermined cutoffs. 0.03% (>30 ng/mL). It more replete, difference arise. adds valuable area medicine becoming increasingly relevant. plays folliculogenesis embryonic blastulation defined clearly needed. Nevertheless, current techniques, global epidemic exists reproductive-aged taking supplements. Future should aim assess accurately identify deficient Impact implantation—a transferFertility SterilityVol. 115Issue 3PreviewTo 25-hydroxyvitamin [25(OH)D] immediately analyze early outcome parameters biochemical pregnancy, rate, rates ovarian hyperstimulation. Full-Text