title: Vitamin D deficiency and infertility: insights from in vitro fertilization cycles.
abstract: BACKGROUND
  Vitamin D deficiency has been proven to affect fertility in mammals, but data in human is less convincing. In particular, data on in vitro fertilization (IVF), an attractive model to draw information on this topic, are sparse and conflicting.
  
  
  OBJECTIVE
  Our objective was to investigate IVF outcome in women with deficient 25-hydroxy-vitamin D [25(OH)D] serum levels (<20 ng/mL).
  
  
  METHODS
  This prospective cross-sectional study was conducted at the infertility unit of an academic setting.
  
  
  METHODS
  The main inclusion criteria were as follows: (1) indication to IVF, (2) age 18-42 years, (3) BMI 18-25 kg/m(2), (4) adequate ovarian reserve according to Bologna criteria. Eligible women provided a serum sample for 25(OH)D measurement at the time of cycle preparation. Subjects were subsequently excluded if the cycle was cancelled or if the attempt was excessively delayed.
  
  
  METHODS
  Quantitative detection of serum 25(OH)D.
  
  
  METHODS
  Clinical pregnancy rate.
  
  
  RESULTS
  The number of recruited women with serum 25(OH)D <20 ng/mL and ≥ 20 ng/mL was 154 and 181, respectively. The clinical pregnancy rates were 20% (30/154) and 31% (56/181), respectively (P = .02); the adjusted odds ratio for clinical pregnancy in women with vitamin D ≥ 20 ng/mL was 2.15 (95% CI: 1.23-3.77). Subgroup analyses showed that the group of women with the highest serum levels (>30 ng/mL) had the highest chances of pregnancy.
  
  
  CONCLUSIONS
  Vitamin D is an emerging factor influencing female fertility and IVF outcome. Additional studies are pressingly needed to confirm a causal relationship and to investigate the potential therapeutic benefits of vitamin D supplementation.
authors.affiliation: Fondazione IRCCS Ca' Granda (A.P., S.F., A.T., L.F., E.S.), Ospedale Maggiore Policlinico, 20122, Milan, Italy; Obstetrics and Gynecology Unit (P.V., L.P., E.P.), San Raffaele Scientific Institute, 20132, Milan, Italy; Università Vita-Salute (M.C.), San Raffaele Scientific Institute, 20132, Milan, Italy; and University of Milan (L.F.), via Festa del Perdono 8, 20122, Milan, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Paffoni
authors.forename: Stefania
authors.initials: S
authors.lastname: Ferrari
authors.forename: Paola
authors.initials: P
authors.lastname: Viganò
authors.forename: Luca
authors.initials: L
authors.lastname: Pagliardini
authors.forename: Enrico
authors.initials: E
authors.lastname: Papaleo
authors.forename: Massimo
authors.initials: M
authors.lastname: Candiani
authors.forename: Amedea
authors.initials: A
authors.lastname: Tirelli
authors.forename: Luigi
authors.initials: L
authors.lastname: Fedele
authors.forename: Edgardo
authors.initials: E
authors.lastname: Somigliana
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000097:blood / Q000150:complications*; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications*; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D