Incidence of Respiratory Disorders in Neonates Born between 34 and 36 Weeks of Gestation Following Exposure to Antenatal Corticosteroids between 24 and 34 Weeks of Gestation

ABSTRACT

We studied the effect of antenatal corticosteroids on the incidence of respiratory disorders in singleton neonates born between 34 and 36 weeks of gestation. Retrospective analysis was conducted of the incidence of respiratory distress syndrome (RDS) and other respiratory disorders (need for mechanical ventilation, continuous positive airway pressure, and prolonged oxygen therapy) among singleton neonates delivered between 34 and 36 weeks of gestation who were exposed to antenatal corticosteroids, compared with neonates who were not exposed. Statistical analyses included two-tailed t tests, two-way analysis of variance for continuous data, and chi-square analysis for ratios. A probability of 0.05 was considered significant. Between January 1, 2000, and December 31, 2004, 1078 neonates were born between 34 and 36 weeks of gestation. Information regarding antenatal corticosteroids was available in 1044: 574 neonates (53.2%) were exposed to antenatal corticosteroids and 470 (43.6%) were not. One thousand and eighteen neonates were admitted to the neonatal intensive care unit. Respiratory disorders were diagnosed in 140 of those exposed to antenatal steroids (24.4%) and in 382 of the nonexposed (81.3%) (p < 0.0001). Two hundred and ten neonates (20.6%) developed RDS: Of those, 43 were exposed to antenatal corticosteroids and 167 were not (incidence of RDS was 7.5% and 35.5%, respectively; p = 0.0001). The beneficial effects of corticosteroids were similar in both genders. It appears that the exposure of singleton pregnancies to antenatal corticosteroids between 24 and 34 weeks of gestation is associated with a significantly lower incidence of respiratory disorders among neonates born at 34 to 36 weeks of gestation. Further studies are needed to determine whether administering antenatal steroids to women experiencing preterm labor after 34 weeks of gestation would be associated with a similar beneficial effect.

KEYWORDS

Antenatal - corticosteroids - respiratory - neonates - preterm

REFERENCES

• 1 Grier D G, Halliday H L. Effects of glucocorticoids on fetal and neonatal lung development.  Treat Respir Med. 2004;  3 295-306
• 2 Liggins G C, Howie R. A controlled trial of antepartum glucocorticoid treatment for prevention of the respiratory distress syndrome in premature infants.  Pediatrics. 1972;  50 515-525
• 3 Liggins G C. Premature delivery of foetal lambs infused with glucocorticoids.  J Endocrinol. 1969;  45 515-523
• 4 Gilstrap L C, Christensen R, Clewell W, D'Alton M . National Institute of Health Consensus Development Conference Statement. Effect of corticosteroids for fetal maturation on perinatal outcomes.  Am J Obstet Gynecol. 1994;  173 246-252
• 5 American College of Obstetricians and Gynecologists (ACOG) .Antenatal Corticosteroid Therapy for Fetal Maturation. Committee Opinion number 273 May 2002
• 6 Gilstrap L C, Hightower E S, Clewell W, D'Alton M . Antenatal corticosteroids revisited: repeat courses.  NIH Consensus Statement. 2000;  17 1-10
• 7 Senat M V. Corticosteroid for fetal lung maturation: indication and treatment protocols.  J Gynecol Obstet Biol Reprod (Paris). 2002;  31 5S105-13
• 8 Purdy I B, Wiley D J. Perinatal corticosteroids: a review of research. Part I: Antenatal administration.  Neonatal Netw. 2004;  23 15-30
• 9 Morrison J J, Renie J M, Milton P J. Neonatal respiratory morbidity and mode of delivery at term: influence of timing of elective caesarean section.  Br J Obstet Gynaecol. 1995;  102 101-106
• 10 Stutchfield P, Whitaker R, Russell I. Antenatal betamethasone and incidence of neonatal respiratory distress after elective caesarean section: pragmatic randomised trial.  BMJ. 2005;  331 662-664
• 11 Peaceman A M, Bajaj K, Kumar P, Grobman W A. The interval between a single course of antenatal steroids and delivery and its association with neonatal outcomes.  Am J Obstet Gynecol. 2005;  193 1165-1169