Steroid profiling in the amniotic fluid: reference range for 12 steroids and interest in 21-hydroxylase deficiency.

INTRODUCTION: Determination of steroid levels in the amniotic fluid gives some insight on foetal adrenal and gonadal functions. Our objectives were to establish reference ranges of 12 steroid levels throughout pregnancy and to compare them with steroid levels from pregnancies with foetuses presenting 21-hydroxylase deficiency (21OHD).

MATERIALS AND METHODS: Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was applied to 145 "control" amniotic fluid samples from gynaecology activity (12 + 6 to 32 + 4 Gestational Weeks, GW). The following steroids were analysed according to gestational age and compared to 23 amniotic fluid samples from foetuses with classic 21-hydroxylase deficiency confirmed by molecular studies: delta-4-androstenedione (D4), dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17OHP), 11-deoxycortisol (11OH), 21-deoxycortisol (21OH), corticosterone, deoxycorticosterone (DOC), testosterone, pregnenolone, 17-hydroxypregnenolone (17Pregn), cortisol and cortisone. Chromosomal sex was determined by karyotype and gestational age by biometric measurements.

RESULTS: Analysis of "control" samples showed a statistically significant difference for D4 and testosterone levels according to foetal sex. Cortisol, corticosterone, and DOC had lower concentrations before 20 GW than after 20 GW, whereas 17Pregn and pregnenolone had higher concentrations before 20 GW. This allowed us to establish age- and sex-dependant reference values. We observed higher 21OH, 17Pregn, D4 and testosterone levels in females 21OHD than female controls. The ratios 17OHP/17Pregn, D4/DHEA and 11OH/17OHP appeared discriminant for the diagnosis of 21OHD.

CONCLUSION: Our study provides information on foetal steroidogenesis and suggests reference values for 12 steroids during pregnancy. This allows a prenatal diagnosis of 21-hydroxylase deficiency within 24 hours and might be useful in the diagnosis of other variations of sex development (VSD).