Dynamic changes in LH/FSH ratios in infants with normal sex development

Area of Science:

• Pediatric Endocrinology
• Reproductive Endocrinology
• Biomarker Discovery

Background:

• The ratio of luteinizing hormone (LH) to follicle-stimulating hormone (FSH) is not well-established in infancy.
• Understanding hormonal profiles in infants is crucial for assessing reproductive health and development.

Purpose of the Study:

• To evaluate serum and urinary LH/FSH ratios as potential markers for sex determination in healthy infants.
• To establish age-specific cutoffs for LH/FSH ratios in differentiating sexes during early childhood.

Main Methods:

• A prospective, longitudinal cohort study involving 236 healthy infants (0-1.2 years).
• Collection and analysis of 567 serum and 603 urine samples.
• Assessment of diagnostic accuracy, including sensitivity and specificity, for LH/FSH ratios in sex determination.

Main Results:

• LH/FSH ratios in both serum and urine were significantly higher in males with minimal overlap between sexes.
• LH/FSH ratios demonstrated excellent accuracy in distinguishing sex from birth to 1.2 years.
• Median sensitivities and specificities ranged from 93% to 100% with narrow confidence intervals.

Conclusions:

• Serum and urinary LH/FSH ratios are highly effective discriminators of sex in healthy infants throughout the first year of life.
• The findings suggest the LH/FSH ratio can be a valuable tool in pediatric diagnostics.
• Further research is needed to clarify the clinical applications of these hormonal ratios.