Antenatal Glucocorticoid Exposure Research Articles

Direct fetal glucocorticoid treatment alters postnatal adaptation in premature newborn baboons.

Abnormalities of premature newborn adaptation after preterm birth result in significant perinatal mortality and morbidity. We assessed the effects of short-term (24 h) fetal betamethasone exposure on preterm newborn baboon pulmonary and cardiovascular regulation and renal sodium handling during the first 24 h after birth. Male fetal baboons (Papio) (124-day gestation, term 185 days) received ultrasound-guided intramuscular injections of saline (n = 5) or betamethasone (0.5 mg/kg; n = 5). Fetuses were cesarean delivered 24 h later, treated with 100 mg/kg surfactant, and ventilated by adjusting peak inspiratory pressures to maintain PCO2 values of 35-50 mmHg for 24 h. Betamethasone- vs. saline-treated mean +/- SE newborn body weights (0.45 +/- 0.02 vs. 0.41 +/- 0.01 kg) were similar. Although prenatal betamethasone did not affect postnatal lung function (PCO2, arterial/alveolar O2 gradient, or dynamic compliance), plasma hormone (cortisol or thyroxine), or catecholamine levels, mean arterial pressure (25 +/- 1 vs. 32 +/- 1 mmHg), plasma sodium concentration (132 +/- 2 vs. 138 +/- 1 meq/l), glomerular filtration rate (0.07 +/- 0.02 vs. 0.16 +/- 0.02 ml.min-1.kg-1), and renal total sodium reabsorption (1.5 +/- 0.5 vs. 16.0 +/- 3.0 mu eq.min-1.kg-1) values were significantly lower in saline-treated than in betamethasone-treated newborns at 24 h. We conclude that despite the fact that there are no pulmonary and endocrine effects, antenatal glucocorticoid exposure alters premature newborn baboon vascular and renal glomerular function and improves sodium reabsorption after preterm delivery.

Do twins mature earlier than singletons? Results from a matched cohort study

OBJECTIVE: Our purpose was to determine whether, as a consequence of advanced maturity, preterm twin infants have a more favorable neonatal outcome than matched singleton infants. STUDY DESIGN: A matched cohort study design was used. Two hundred twenty-four twin infants (112 sets) were matched for gestational age, race, gender, and mode of delivery with singleton infants who were delivered because of refractory preterm labor. Pregnancies with maternal medical disease including preeclampsia, premature rupture of membranes, twin-twin transfusion syndrome, and known fetal anomalies were excluded. Information was obtained by review of maternal and neonatal charts. RESULTS: There was no difference in the incidence of neonatal death (5% vs 7%, p = 0.66), respiratory distress syndrome (38% vs 35%, p = 0.54), grades 3 and 4 intraventricular hemorrhage (5% vs 4%, p = 0.63), grades 2 and 3 necrotizing enterocolitis (4% vs 6%, p = 0.52), and 5-minute Apgar score ≤6 (21% vs 21%, p = 1.00). Twins had a higher incidence of admission to the Special Care Unit (88% vs 72%, p <0.001). Results were similar when analysis was limited to presenting twins, nonpresenting twins, and twins concordant with controls for antenatal glucocorticoid exposure. CONCLUSION: Twin infants do not have accelerated maturation and improved neonatal outcome compared with matched singleton infants born at the same gestational age because of preterm labor. (Am J Obstet Gynecol 1997;176:1193-9.)