title: The effect of plurality and obesity on betamethasone concentrations in women at risk for preterm delivery.
abstract: OBJECTIVE
  Antenatal corticosteroids (ACS) decrease respiratory distress syndrome in singleton gestations. Twin data are less clear. Obesity and body mass index (BMI) also affect medication distribution volume. We evaluated whether maternal or neonatal cord betamethasone concentrations differed in twin gestations or obese patients.
  
  
  METHODS
  Participants receiving betamethasone in a randomized controlled trial of weekly ACS were identified. We analyzed maternal delivery and cord serum betamethasone concentrations comparing singletons with twins and obese (BMI > or =30 kg/m(2)) with nonobese women.
  
  
  RESULTS
  Fifty-five maternal and 45 cord blood samples were available. Unadjusted median maternal serum concentrations appeared paradoxically higher in both twin gestations and the obese. However, after controlling for confounders, there were no differences in betamethasone concentrations in maternal serum or cord blood between singletons and twins (P = .61 vs P = .14) or nonobese and obese women (P = .67 vs .12).
  
  
  CONCLUSIONS
  Maternal and umbilical cord blood serum betamethasone concentrations are not different in twin gestations or obese women.
authors.affiliation: Department of Obstetrics and Gynecology at Columbia University, New York, NY, USA. cg2231@columbia.edu
authors.forename: Cynthia
authors.initials: C
authors.lastname: Gyamfi
authors.forename: Lisa
authors.initials: L
authors.lastname: Mele
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wapner
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Spong
authors.forename: Alan
authors.initials: A
authors.lastname: Peaceman
authors.forename: Yoram
authors.initials: Y
authors.lastname: Sorokin
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Dudley
authors.forename: Francee
authors.initials: F
authors.lastname: Johnson
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Leveno
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mercer
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
authors.forename: Mary J
authors.initials: MJ
authors.lastname: O'Sullivan
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
authors.forename: Marshall
authors.initials: M
authors.lastname: Carpenter
authors.forename: Dwight J
authors.initials: DJ
authors.lastname: Rouse
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Baha
authors.initials: B
authors.lastname: Sibai
mesh_terms: D001623:Betamethasone / Q000097:blood* / Q000627:therapeutic use; D015992:Body Mass Index; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005938:Glucocorticoids / Q000097:blood* / Q000627:therapeutic use; D006801:Humans; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood*; D011247:Pregnancy; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000517:prevention & control; D014427:Twins
chemical_list: D005938:Glucocorticoids; D001623:Betamethasone