title: Vitamin D deficiency and pregnancy rates in women undergoing single embryo, blastocyst stage, transfer (SET) for IVF/ICSI.
abstract: OBJECTIVE
  What is the influence of vitamin D deficiency on pregnancy rates among women undergoing IVF/ICSI and Day 5 (blastocyst stage) single embryo transfer (SET)?
  
  
  CONCLUSIONS
  Vitamin D deficiency results in significantly lower pregnancy rates in women undergoing single blastocyst transfer.
  
  
  BACKGROUND
  Preliminary experiments have identified the presence of vitamin D receptors in the female reproductive system. However, results regarding the effect of vitamin D deficiency on clinical outcomes are conflicting. None of the previous studies adopted a SET strategy.
  
  
  METHODS
  Serum vitamin D concentration was measured retrospectively in patients who underwent SET on Day 5. Overall 368 consecutive infertile women treated within a period of 15 months were included in the study.
  
  
  METHODS
  All patients underwent ovarian stimulation for IVF/ICSI and Day 5 SET. Serum samples were obtained 7 days prior to embryo transfer and stored frozen at -20°C. Samples were collectively analyzed for their 25-OH vitamin D content. Vitamin D deficiency was defined as serum 25-OH vitamin D levels <20 ng/ml in accordance with the Institute of Medicine and the Endocrine Society clinical practice guidelines.
  
  
  RESULTS
  Clinical pregnancy rates were significantly lower in women with vitamin D deficiency compared with those with higher vitamin D values (41 versus 54%, P = 0.015).Logistic regression analysis was performed to identify whether vitamin D deficiency is independently associated with clinical pregnancy rates after controlling for 16 potential confounding factors. According to our results vitamin D deficiency was independently associated with lower clinical pregnancy rates, odds ratios [ORs (95% confidence interval (CI) 0.61 (0.39-0.95)] for vitamin D deficiency (deficient versus non-deficient women), P = 0.030. Finally, even when restricting our analysis to women undergoing elective SET (274 patients), vitamin D deficiency was again independently associated with pregnancy rates [OR (95% CI) 0.56 (0.33-0.93), P = 0.024].
  
  
  CONCLUSIONS
  Our results refer only to patients undergoing Day 5 SET. Although vitamin D deficiency appears to compromise pregnancy rates in this population, no guidance can be provided regarding a potential relationship between vitamin D deficiency and ovarian reserve or response to ovarian stimulation.
  
  
  CONCLUSIONS
  Vitamin D deficiency impairs pregnancy rates in women undergoing single blastocyst transfer. Future prospective confirmatory studies are needed to validate our results and examine the exact underlying mechanism by which vitamin D levels may impair pregnancy rates in infertile women undergoing IVF/ICSI.
  
  
  BACKGROUND
  None declared.
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium n.polyzos@gmail.com nikolaos.polyzos@uzbrussel.be.
authors.forename: Nikolaos P
authors.initials: NP
authors.lastname: Polyzos
authors.affiliation: Laboratory of Hormonology and Tumormarkers, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Ellen
authors.initials: E
authors.lastname: Anckaert
authors.affiliation: Laboratory of Hormonology and Tumormarkers, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium Grupo PRANOR, Lima, Perú
authors.forename: Luis
authors.initials: L
authors.lastname: Guzman
authors.affiliation: Laboratory of Hormonology and Tumormarkers, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Schiettecatte
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
authors.forename: Lisbet
authors.initials: L
authors.lastname: Van Landuyt
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
authors.forename: Michel
authors.initials: M
authors.lastname: Camus
authors.affiliation: Laboratory of Hormonology and Tumormarkers, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Smitz
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
authors.forename: Herman
authors.initials: H
authors.lastname: Tournaye
mesh_terms: D000328:Adult; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000150:complications*; D011247:Pregnancy; D018873:Pregnancy Rate; D056826:Single Embryo Transfer; D020554:Sperm Injections, Intracytoplasmic; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D
keywords: IVF; pregnancy; single embryo transfer; vitamin D deficiency