Role of fetal sex in the outcome of antenatal glucocorticoid treatment to prevent respiratory distress syndrome: systematic review and meta-analysis.

BACKGROUND: Antenatal glucocorticoid (AGC) therapy has been associated with a decrease in respiratory distress syndrome (RDS). While preterm males remain at greater risk of RDS than females, the role of fetal sex in AGC response is not well known. OBJECTIVES: To review the available evidence regarding the effect of fetal sex in the prevention of RDS using AGC. METHOD: We conducted a systematic review and meta-analysis of RCTs to compare the effect of AGC in male and female infants with regard to the rates of RDS, intra-ventricular hemorrhage (IVH) grades III and IV, and neonatal mortality. Random effects with 95% confidence intervals were assessed in both groups and relative risks were compared using mixed regression. RESULTS: From 248 potentially eligible articles, we included eight in the analysis for a total of 1109 male and 968 female infants. Both male and female infants had a significant decrease in the risks, but no difference between the sexes was observed in terms of reduction in RDS (RR 0.50; 95% CI 0.33 to 0.77 for males, and RR 0.57; 95% CI 0.43 to 0.75 for females, P = 0.99), reduction in IVH (P = 0.98), and reduction in neonatal mortality (P = 0.43). In a sub-analysis, use of betamethasone was associated with a significant decrease in the rate of RDS in males (RR 0.29; 95% CI 0.15 to 0.57) but dexamethasone was not (RR 0.78; 95% CI 0.57 to 1.07). Conversely, dexamethasone use was significantly helpful in females (RR 0.51; 95% CI 0.32 to 0.81) but betamethasone was not (RR 0.62; 95% CI 0.38 to 1.00). CONCLUSION: The effect of AGC for prevention of RDS is similar in females and males. However, futures studies should investigate the type of AGC according to fetal/neonatal sex.

Early postnatal dexamethasone decreases hepatocyte growth factor in tracheal aspirate fluid from premature infants.

OBJECTIVE: To evaluate in preterm infants the effect of dexamethasone on hepatocyte growth factor (HGF), an epithelial cell mitogen, and on vascular endothelial growth factor (VEGF), an endothelial cell mitogen, in tracheal aspirate fluid (TAF). METHODS: Thirty preterm infants (birth weight: 1000-1500 g) with respiratory distress syndrome were randomized to receive dexamethasone or to serve as control subjects. Dexamethasone was started at the age of 12 to 24 hours at a dose of 0.5 mg/kg/d for 2 days and 0.25 mg/kg/d for the subsequent 2 days. HGF and VEGF levels were examined from TAF samples during the first postnatal week. For eliminating the effect of dilution, the concentration of the secretory component of immunoglobulin A was determined. Student t test, 1-way analysis of variance, chi2, and simple regression analysis were used for statistical analysis. RESULTS: Mean HGF concentrations were similar in the dexamethasone and control groups on days 1 to 2, but the dexamethasone group had a lower mean HGF concentration on days 3 to 4 and 5 to 7. In contrast, no differences existed in mean VEGF levels between the dexamethasone and control groups. CONCLUSIONS: In preterm infants who received early postnatal dexamethasone, reduced levels of HGF were seen in tracheal aspirates. This reduction may participate in the suppressive effects of dexamethasone on lung development.