title: Maternal selenium-supplementation at various stages of periconception period: influence on murine blastocyst morphology and implantation status.
abstract: BACKGROUND
  Selenium is one of the trace minerals whose deficiency is known to lead to complications of female reproduction. The identified gaps in researches regarding selenium and pregnancy include optimizing the dosage of selenium supplementation, timing of supplementation, finding the best form and type of selenium, and selenium administration combined with other antioxidants. Hence, this study was conceptualized to address one of the identified gaps, that is, to find out the best timing of selenium administration around the time of pregnancy. Specifically, this study aimed to assess the effects of maternal Selenium-supplementation, administered at various stages of periconception period, on murine blastocyst morphology, percent occurrence of good quality blastocysts, and implantation status.
  
  
  METHODS
  ICR female mice were randomly assigned into the unsupplemented group (Group I) receiving basal diet without selenium, and treatment groups given with 3.0 μg selenium-supplement per day during pregestation only (Group II), pregestation-throughout-gestation (Group III) and gestation only (Group IV). Both blastocyst morphology and implantation status were assessed.
  
  
  RESULTS
  The morphometric measurements of blastocysts appeared to be unaffected by selenium-supplementation at different stages of periconception. Selenium-supplementation at pregestation only (Group II) and gestation only (Group IV) produced higher percent occurrence of good quality blastocysts and lower percent pre-implantation loss than Group III. Among all the treatment groups, Group III (Selenium-supplementation during pregestation-to-gestation) yielded the lowest quality blastocysts and highest percent pre-implantation loss.
  
  
  CONCLUSIONS
  Maternal selenium-supplementation during pregestation and gestation stages of the periconception period yielded a high percent occurrence of good quality blastocysts and pre-implantation success.
authors.affiliation: Biology Department, College of Science, De La Salle University, Taft Avenue, Manila, 1004 Philippines.
authors.forename: Mark Anthony C
authors.initials: MAC
authors.lastname: Mamon
authors.affiliation: Biology Department, College of Science, De La Salle University, Taft Avenue, Manila, 1004 Philippines.
authors.forename: Gliceria B
authors.initials: GB
authors.lastname: Ramos
keywords: Blastocyst morphometry; Periconception period; Post-implantation loss; Pre-implantation loss; Selenium-supplementation; Trace mineral