ESPE Abstracts (2018) 89 P-P1-223

Sex-Differences in Reproductive Hormones During Mini-Puberty in Infants with Normal and Disordered Sex Development

Trine Holm Johannsena, Katharina M Maina, Marie Lindhardt Ljubicica, Tina Kold Jensena,b,c, Helle Raun Andersenb, Marianne Skovsager Andersend, Jørgen Holm Petersene, Anna-Maria Anderssona & Anders Juula

aDepartment of Growth and Reproduction, Rigshospitalet, University Hospital of Copenhagen; and International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; bDepartment of Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark; cHans Christian Andersen Children’s Hospital, Odense University Hospital, Odense, Denmark; dDepartment of Endocrinology, Odense University Hospital, Odense, Denmark; eDepartment of Biostatistics, University of Copenhagen, Copenhagen, Denmark

Context: The early activation of the hypothalamic-pituitary-gonadal axis during infancy can be used in the evaluation of infants suspected of disorders of sex development (DSD). However, few data exists on sex-specific reference ranges for these hormones during early life.

Objective: To evaluate sex-differences in reproductive hormone concentrations in serum from healthy infants in order to define sex-specific cut-off values and to apply these in infants with DSD.

Design: A cross-sectional study.

Setting: A tertiary center for pediatric endocrinology at the University Hospital of Copenhagen.

Patients or other participants: 1840 healthy infants and 27 DSD patients aged 2–5 months.

Main outcome measures: Serum concentrations of LH, FSH, testosterone, estradiol, SHBG, inhibin B, AMH, DHEA, DHEAS, 17-OHP, androstenedione, and LH/FSH-ratio.

Results: LH and FSH concentrations showed overlap between sexes with LH being highest in boys and FSH being highest in girls. The LH/FSH-ratio separated infant boys from girls with minimal overlap at a cut-off value of 0.32. Inhibin B and AMH concentrations were markedly higher in boys compared to girls, with minimal or no overlap, respectively. In infants with Klinefelter syndrome, 45,X/46,XY mosaicism and male phenotype, and Turner syndrome, respectively, the LH/FSH-ratio matched the gender-of-rearing. However, infants with complete androgen insensitivity syndrome had LH/FSH-ratios within male range.

Conclusions: Reference ranges for reproductive hormones and LH/FSH-ratio during mini-puberty were established in this study. The classifiers that best separated sex in mini-puberty were AMH, LH/FSH-ratio and testosterone. Use of the LH/FSH-ratio may add valuable information in the work-up of infants suspected of DSD.