title: Effect of antenatal corticosteroids on fetal growth and gestational age at birth.
abstract: OBJECTIVE
  To estimate the effect of multiple courses of antenatal corticosteroids on neonatal size, controlling for gestational age at birth and other confounders, and to determine whether there was a dose-response relationship between number of courses of antenatal corticosteroids and neonatal size.
  
  
  METHODS
  This is a secondary analysis of the Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study, a double-blind randomized controlled trial of single compared with multiple courses of antenatal corticosteroids in women at risk for preterm birth and in which fetuses administered multiple courses of antenatal corticosteroids weighed less, were shorter, and had smaller head circumferences at birth. All women (n=1,858) and children (n=2,304) enrolled in the Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study were included in the current analysis. Multiple linear regression analyses were undertaken.
  
  
  RESULTS
  Compared with placebo, neonates in the antenatal corticosteroids group were born earlier (estimated difference and confidence interval [CI]: -0.428 weeks, CI -0.10264 to -0.75336; P=.01). Controlling for gestational age at birth and confounding factors, multiple courses of antenatal corticosteroids were associated with a decrease in birth weight (-33.50 g, CI -66.27120 to -0.72880; P=.045), length (-0.339 cm, CI -0.6212 to -0.05676]; P=.019), and head circumference (-0.296 cm, -0.45672 to -0.13528; P<.001). For each additional course of antenatal corticosteroids, there was a trend toward an incremental decrease in birth weight, length, and head circumference.
  
  
  CONCLUSIONS
  Fetuses exposed to multiple courses of antenatal corticosteroids were smaller at birth. The reduction in size was partially attributed to being born at an earlier gestational age but also was attributed to decreased fetal growth. Finally, a dose-response relationship exists between the number of corticosteroid courses and a decrease in fetal growth. The long-term effect of these findings is unknown.
  
  
  BACKGROUND
  ClinicalTrials.gov, www.clinicaltrials.gov, NCT00187382.
  
  
  METHODS
  II.
authors.affiliation: Department of Obstetrics and Gynaecology and Paediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada. kmurphy@mtsinai.on.ca
authors.forename: Kellie E
authors.initials: KE
authors.lastname: Murphy
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Willan
authors.forename: Mary E
authors.initials: ME
authors.lastname: Hannah
authors.forename: Arne
authors.initials: A
authors.lastname: Ohlsson
authors.forename: Edmond N
authors.initials: EN
authors.lastname: Kelly
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Matthews
authors.forename: Saroj
authors.initials: S
authors.lastname: Saigal
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Asztalos
authors.forename: Susan
authors.initials: S
authors.lastname: Ross
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Delisle
authors.forename: Kofi
authors.initials: K
authors.lastname: Amankwah
authors.forename: Patricia
authors.initials: P
authors.lastname: Guselle
authors.forename: Amiram
authors.initials: A
authors.lastname: Gafni
authors.forename: Shoo K
authors.initials: SK
authors.lastname: Lee
authors.forename: B Anthony
authors.initials: BA
authors.lastname: Armson
mesh_terms: D000328:Adult; D001623:Betamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D001724:Birth Weight / Q000187:drug effects*; D001827:Body Height / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D005865:Gestational Age; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D011247:Pregnancy; D047928:Premature Birth
chemical_list: D005938:Glucocorticoids; D001623:Betamethasone