Whether vitamin D was associated with clinical outcome after IVF/ICSI: a systematic review and meta-analysis

BACKGROUND: There exist contradictive views on whether the vitamin D has association with clinical outcome of in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI). The present meta-analysis aim to establish whether vitamin D was associated with clinical outcomes of IVF/ICSI. METHODS: MEDLINE, Google Scholar and the Cochrane Library from database inception to March 2017 were searched. Clinical studies, which evaluated the association of vitamin D level and the clinical outcomes after IVF/ICSI, were included. The Main Outcome Measures were clinical pregnancy, ongoing pregnancy, and live birth. RESULTS: In the analysis of clinical pregnancy, 9 cohort studies were included. Of which, 2 studies and 3 studies were identified in analyzing ongoing pregnancy and live birth, respectively. Meta-analysis showed trends toward lower clinical pregnancy [RR 0.91, (95% CI 0.77–1.07)] and higher ongoing pregnancy [RR 1.06, (95% CI 0.95–1.19)] for women with deficient level of vitamin D. The probability of live birth for women with deficient level of vitamin D was significantly lower than cases with sufficient level of vitamin D [RR 0.74, (95% CI 0.58–0.90)]. CONCLUSIONS: Deficient vitamin D was associated with decreased probability of live birth after IVF/ICSI. So vitamin D should be supplied to women with deficient level vitamin D. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12958-018-0324-3) contains supplementary material, which is available to authorized users.