Neonatal reference intervals for salivary steroids: focus on prematurity, stressful events and perinatal betamethasone

Context Painlessly obtained samples can improve diagnostics and care in paediatric conditions with affected steroidogenesis. Objective To establish neonatal reference intervals (RIs) and identify sources of biological variation for steroid hormones in saliva. Methods Steroid concentrations were determined using LC-MS/MS in 412 saliva samples from 174 infants aged 0-4 weeks, born at gestational age 26–42 weeks, recruited from three neonatal intensive care units and one maternity ward. We used six approaches to construct RIs with partitioning based on results from linear mixed models. Results RIs in nmol/L calculated with robust method using median of up to six samples with sufficient volume from each infant were for salivary 17OH-pregnenolone: <4.0; 17OH-progesterone: <2.5; 11-deoxycortisol: 0.02–0.99; 21-deoxycortisol: <0.2; cortisol: 0.65–39; cortisone: 18–154; deoxycorticosterone: <0.04; corticosterone: <0.76; aldosterone: 0.21–4.2; dehydroepiandrosterone: <2.4; dehydroepiandrosterone sulphate: <100; androstenedione: <1.5; testosterone girls: <0.10; testosterone boys: <0.32. Following multivariable adjustment, prematurity was associated with elevated concentrations of mineralocorticoids, androgens and glucocorticoid-precursors (up to 240%, 500% and 1060% respectively), but not cortisol or cortisone. Being on respiratory support was linked with qualitative and quantitative changes in all corticosteroid pathways, while sampling during the first 48 h of life was associated with an increase in adrenocorticotropin-regulated glucocorticoids and androgens (except dehydroepiandrosterone) but not mineralocorticoids. Perinatal exposure to synthetic glucocorticoids led to 33% reduction in salivary cortisol, but not other hormones. Betamethasone was detectable in infants' saliva up to 12 days following maternal administration. Conclusions We present neonatal reference intervals for steroid hormones in saliva thereby supporting a non-invasive and painless option for obtaining a steroid hormone profile in this fragile population.