Fetal sex and prenatal betamethasone therapy

Area of Science:

• Neonatal Medicine
• Endocrinology
• Obstetrics

Background:

• Respiratory distress syndrome (RDS) is a significant cause of morbidity and mortality in premature infants.
• Prenatal corticosteroid administration, such as betamethasone, is a standard treatment to mature fetal lungs and reduce RDS incidence.
• Emerging evidence suggests potential sex-based differences in treatment efficacy.

Purpose of the Study:

• To investigate the influence of fetal sex on the effectiveness of maternal betamethasone treatment in preventing RDS in premature infants.
• To explore potential mechanisms underlying any observed sex differences in treatment response.

Main Methods:

• Retrospective analysis of premature infants born between 1,251 and 1,750 gm birth weight who received maternal betamethasone treatment.
• Comparison of RDS incidence between male and female infants.
• Measurement of cord serum betamethasone levels and assessment of fetal hypothalamic-pituitary-adrenal axis response (serum cortisol, dehydroepiandrosterone sulfate, growth hormone suppression).

Main Results:

• The incidence of RDS was significantly higher in male infants (40.9%) compared to female infants (7.1%) (P = 0.03) among treated infants within the specified birth weight range.
• Cord serum betamethasone levels were similar between sexes.
• No sex-based differences were observed in the suppression of serum cortisol, dehydroepiandrosterone sulfate, or growth hormone following betamethasone treatment.

Conclusions:

• Prenatal betamethasone therapy appears to be less effective in preventing RDS in male premature infants compared to female infants.
• The reduced efficacy in males is not attributable to differences in betamethasone transfer, metabolism, or fetal hypothalamic-pituitary-adrenal axis responsiveness.