Does corticosteroid therapy impact fetal pulmonary artery blood flow in women at risk for preterm birth?
OBJECTIVE
Maternal corticosteroid administration in pregnancy is known to enhance fetal lung maturity in at risk fetuses. The aim of this study was to test the hypothesis that corticosteroid therapy alters fetal pulmonary blood flow in pregnancies at risk for preterm birth (PTB).


METHODS
We prospectively evaluated main fetal pulmonary artery (MPA) blood flow in pregnant women at risk for PTB and treated with corticosteroids (betamethasone), compared to an uncomplicated cohort without steroid therapy. The Doppler indices of interest included Peak Systolic Velocity (PSV), Resistive Index (RI), Pulsatility Index (PI), Systolic/Diastolic ratio (S/D ratio), Acceleration Time (AT), and Acceleration Time/Ejection Time Ratio (AT/ET ratio), with the latter serving as the primary outcomes due to its stability irrespective of gestational age.


RESULTS
When compared with controls, fetuses treated with corticosteroids demonstrated significantly decreased pulmonary artery acceleration time (median: 28.89 (22.22-51.11) vs. 33.33 (22.20-57.00), p=0.006), while all other indices remained similar. We found no difference in pulmonary blood flow between fetuses who developed respiratory distress syndrome (RDS) and those that did not (31.56 +/- 6.842 vs. 32.36 +/- 7.265, p= 0.76).


CONCLUSIONS
Our data demonstrate altered fetal pulmonary blood flow with corticosteroid therapy, possibly due to increased arterial elastance brought on by medication effect, which leads to the decreased acceleration time or possible gestational age affect. Contrary to a recent report, we did not observe any Doppler differences in fetuses with RDS, which underscores the need for further examination of this proposed association.
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
William
W
Lindsley
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
Richard
R
Hale
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
Ashley
A
Spear
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
Jasvant
J
Adusumalli
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
Jasbir
J
Singh
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States.
Kimberly
K
DeStefano
St. David's North Austin Medical Center, Women's Center of Texas, Austin Maternal-Fetal Medicine, Austin, Texas, United States. sinahaeri@gmail.com.
Sina
S
Haeri
D000305:Adrenal Cortex Hormones / Q000494:pharmacology*; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D005260:Female; D005333:Fetus / Q000187:drug effects*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000196:embryology; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal / Q000379:methods*
D000305:Adrenal Cortex Hormones