ABSTRACT
OBJECTIVE: To investigate the potential impact of vitamin D serum levels of couples going through in vitro fertilization in terms of embryo quality and pregnancy rates. DESIGN: Retrospective cohort study SETTING: Fertipraxis, private human reproduction center on Rio de Janeiro, Brazil. SUBJECTS: 267 couples who underwent intracytoplasmic sperm injection between January 2017 and March 2019. EXPOSURE: The couples were categorized into four groups based on 25OH vitamin D levels measured at the beginning of the stimulation protocol: Group 1 with levels ≥ 30 ng/mL for both women and men; Group 2 with levels < 30 ng/mL for both; Group 3 with women < 30 ng/mL and men ≥ 30 ng/mL; and Group 4 with women ≥ 30 ng/mL and men < 30 ng/mL. MAIN OUTCOME MEASURES: We consider quantity and quality of embryos during the cleavage and blastocyst stages as primary outcomes. Correspondingly, clinical pregnancy rate was regarded as a secondary outcome. RESULTS: Our findings revealed no significant correlations between the studied VD groups and the evaluated outcomes. This includes quantity and quality of embryos during the cleavage and blastocyst stages, as well as clinical pregnancy rate. Primary analysis revealed a small but statistically significant difference in the duration of controlled ovarian stimulation between group 1 and group 2 (p=0.035; CI=0.07 - 3.04) and between group 1 and group 3 (p=0.040; CI=0.05 - 3.23). CONCLUSION: The present study found no correlation between the studied VD levels and quantity and quality of cleavage or blastocyst stage embryos, nor did it show any impact on clinical pregnancy rates. Further well designed, prospective studies are warranted to determine whether and how vitamin D affects reproductive outcomes.
