title: Effects of a single course versus repeated courses of antenatal corticosteroids on fetal growth, placental morphometry and the differential regulation of vascular endothelial growth factor.
abstract: OBJECTIVE
  To investigate the impact of antenatal exposure to a single course or repeated courses of dexamethasone (DEX) on neonatal anthropometrics, placental morphometry and potential effect on maternal plasma levels and placental expression of vascular endothelial growth factor (VEGF).
  
  
  METHODS
  Pregnant women between 27 and 32 weeks of gestation who delivered between 28 and 40 weeks and received a single course (n = 38) or repeated courses (n = 33) of DEX were compared to gestational age-matched controls (n = 30). Maternal blood samples were obtained, and placental biopsy was taken. Area percent of VEGF immunostaining and villous capillarization index were evaluated using image analysis.
  
  
  RESULTS
  Infants exposed to repeated courses of DEX were significantly associated with decreased birthweight, body length, head circumference and placental weight compared with controls (P = 0.011, P < 0.001, P = 0.004, P < 0.001, respectively) and with the group that received a single course of DEX (P = 0.021, P = 0.020, P = 0.049, P = 0.010, respectively). There was a significant decrease in maternal VEGF plasma levels and percentage of VEGF immunostained area after repeated courses of DEX compared with controls (P < 0.001 and P = 0.001, respectively) or a single course (P = 0.028 and P = 0.002, respectively). Notably, repeated courses of DEX impaired normal increase in villous capillarization index compared with controls or a single course (P = 0.001 and P = 0.041, respectively).
  
  
  CONCLUSIONS
  Repeated antenatal courses of DEX compromised fetal and placental growth compared with a single course of DEX, and these effects were potentially mediated by altered maternal plasma levels and placental expression of VEGF with consequent decrease in placental vascularization. Because of continuing uncertainties, several key messages for clinicians are provided.
authors.affiliation: Department of Obstetrics and Gynecology, Taibah University, Almadinah Almunawarah, Saudi Arabia; Department of Obstetrics and Gynecology, Zagazig University, Zagazig, Egypt.
authors.forename: Amr K
authors.initials: AK
authors.lastname: Elfayomy
authors.forename: Shaima M
authors.initials: SM
authors.lastname: Almasry
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000187:drug effects; D003907:Dexamethasone / Q000008:administration & dosage / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D006801:Humans; D008431:Maternal-Fetal Exchange / Q000187:drug effects; D010920:Placenta / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D021041:Placental Circulation / Q000187:drug effects; D010929:Placentation / Q000187:drug effects*; D011247:Pregnancy; D042442:Vascular Endothelial Growth Factors / Q000097:blood / Q000378:metabolism*; D055815:Young Adult
chemical_list: D042442:Vascular Endothelial Growth Factors; D003907:Dexamethasone
keywords: antenatal corticosteroid; dexamethasone; neonatal anthropometry; placental morphometry; vascular endothelial growth factor