Influence of vitamin D levels on in vitro fertilization outcomes in donor-recipient cycles

ObjectiveTo elucidate the role of vitamin D in reproduction by examining the relationship between recipient vitamin D levels and pregnancy rates in donor-recipient IVF cycles.DesignRetrospective cohort study.SettingAcademic tertiary care center.Patient(s)Ninety-nine recipients of egg donation at University of Southern California Fertility.Intervention(s)Serum was collected from egg donor recipients before ET and was tested for vitamin D levels [25(OH)D].Main Outcome Measure(s)Clinical pregnancy as defined by sonographic presence of a heartbeat at 7-8 weeks of gestation.Result(s)In a diverse population of 99 recipients (53% Caucasian, 20% Asian, 16% Hispanic, 7% African American), adjusted clinical pregnancy rates were lower among vitamin D-deficient recipients than among vitamin D-replete recipients (37% vs. 78%). Live-birth rates were 31% among vitamin D-deficient recipients, compared with 59% among vitamin D-replete recipients. There were no differences in adjusted clinical pregnancy and live-birth rates among recipients who were vitamin D deficient [25(OH)D<20 ng/mL] vs. among those who were vitamin D insufficient [20 ng/mL ≤ 25(OH)D<30 ng/mL].Conclusion(s)Nonreplete vitamin D status [25(OH)D<30 ng/mL] was associated with lower pregnancy rates in recipients of egg donation. Since the oocyte donor-recipient model is able to separate the impact of vitamin D on oocyte vs. endometrium, these data suggest that the effects of vitamin D may be mediated through the endometrium.