Bone metabolism in fetuses of pregnant women exposed to single and multiple courses of corticosteroids.
OBJECTIVE
To estimate the effect of single and recurrent doses of antenatal corticosteroids on fetal bone metabolism.


METHODS
This was a secondary analysis of a cohort of pregnant women from a previously reported randomized, placebo-controlled, multicenter trial of women at risk for preterm delivery who received weekly courses of betamethasone (active) or placebo after an initial course of corticosteroids. Umbilical cord serum levels of carboxy-terminal carboxy-terminal propeptide of type I procollagen and cross-linked carboxy-terminal telopeptide of type I procollagen were measured to assess the rate of fetal bone formation and resorption, respectively. Analysis was stratified according to number of repeat antenatal study courses of betamethasone or placebo (one to three compared with at least four courses, not including the initial course).


RESULTS
Of the 251 umbilical cord serum samples, the median serum carboxy-terminal telopeptide of type I procollagen levels, but not carboxy-terminal propeptide of type I procollagen levels, was significantly lower with repeat betamethasone exposure (55.0 compared with 57.9 micrograms/L, P=.01). In the fetuses exposed to at least four repeat study courses, there was a significant decrease in median carboxy-terminal telopeptide of type-I procollagen levels between repeat betamethasone exposure and placebo (53.4 compared with 58.6 micrograms/L, respectively, P=.04), but there was no difference between groups in the fetuses exposed to 1-3 repeat study courses (57.4 compared with 56.7 micrograms/L, respectively, P=.29).


CONCLUSIONS
Levels of umbilical cord serum markers of bone resorption but not formation are reduced in fetuses exposed to repeat courses of antenatal betamethasone. Up to four courses of antenatal betamethasone do not seem to affect fetal bone metabolism.


METHODS
II.
Fonseca
Linda
L
From the Department of Obstetrics and Gynecology, University of Texas Health Science Center at Houston, Houston, Texas; Biostatistics Center, George Washington University Biostatistics Center, Rockville, Maryland; Department of Obstetrics and Gynecology, Drexel University College of Medicine, Philadelphia, Pennsylvania; Department of Obstetrics and Gynecology, Ohio State University, Columbus, Ohio; Department of Obstetrics and Gynecology, Northwestern University, Chicago, Illinois; Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI; Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah; National Institute of Child Health and Human Development, Bethesda, Maryland; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Obstetrics and Gynecology, Magee Womens Hospital, Pittsburgh, Pennsylvania; Departments of Obstetrics and Gynecology, Columbia University, New York, New York, and University of Cincinnati, Cincinnati, Ohio; Department of Obstetrics and Gynecology, Case Western Reserve University, Cleveland Ohio; Department of Obstetrics and Gynecology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina; Department of Obstetrics and Gynecology, University of Miami, Miami, Florida; Department of Obstetrics and Gynecology, Brown University, Providence, Rhode Island; Department of Obstetrics and Gynecology, University of Alabama, Birmingham, Alabama; and Department of Obstetrics and Gynecology, University of Tennessee, Memphis, Tennessee.
Ramin
Susan M
SM
Mele
Lisa
L
Wapner
Ronald J
RJ
Johnson
Francee
F
Peaceman
Alan M
AM
Sorokin
Yoram
Y
Dudley
Donald J
DJ
Spong
Catherine Y
CY
Leveno
Kenneth J
KJ
Caritis
Steve N
SN
Miodovnik
Menachem
M
Mercer
Brian
B
Thorp
John M
JM
O'Sullivan
Mary Jo
MJ
Carpenter
Marshall W
MW
Rouse
Dwight J
DJ
Sibai
Baha
B
D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D001623:Betamethasone / Q000008:administration & dosage; D001842:Bone and Bones / Q000378:metabolism*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control; D011247:Pregnancy; D011347:Procollagen / Q000097:blood
D000305:Adrenal Cortex Hormones; D005938:Glucocorticoids; D011347:Procollagen; D001623:Betamethasone