ECE2023 Oral Communications Oral Communications 3: Pituitary and Neuroendocrinology 1 (6 abstracts)
Background and Aim: Congenital growth hormone deficiency (cGHD) is a rare but life-threatening condition whose diagnosis is challenging in the absence of reliable reference values, both in healthy neonates and in preterm ones. We recently estimated GH reference interval in 1036 healthy, at-term newborns (HN) form dried blood spot samples using a previously validated analytical method. Aim of this study is to provide values for random GH in preterm newborns (PN).
Methods: GH was evaluated in 78 PN (M:F 51:49%) attending the Neonatal Intensive Care Unit of Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Milan. GH measurement was performed as above described at 48 hours after birth (GH1). In 41 out of 78 PN a second GH determination (GH2, at 15 days after birth) was also available.
Results: Median (IQR) GH1 values were 14.9 μg/l (9.8-21.1). No gender differences were found (P=0.089). The percentile 5th (3.4 μg/l) calculated in PN was lower than the lower limit of reference interval estimated in HN (reference limit at percentile 5.0th: 7.0 µg/l, 90%CI 6.7-7.3). In PN, decreasing GH levels were associated with increasing invasiveness of ventilation (no ventilation: 20.1, CPAP/biphasic: 15.1, high flows ventilation: 12.4, invasive ventilation: 5.4; overall KW P=0.026). Indeed, GH was significantly lower in PN needing invasive ventilation than not ventilated ones (Bonferonis correction P=0.048). A low-to-moderate, although significant, correlation (rho=0.295, P=0.009), was found between GH levels and gestational age (GA). No association was, instead, found with maternal age (P=0.072), smoke (P=0.138), parity (P=0.520) or other neonatal variables, including jaundice (P=0.276) and auxological parameters (all p>0.05). Considering PN with both GH determinations (n=41), GH1 levels were significantly higher than GH2 (14.4 vs 9.8 μg/l, respectively, P=0.018). GH decreased in most neonates (26/41=63%), as expected after the first week of life. Interestingly, in PN with GH increase (GH2>GH1), GA was significantly lower than in those with GH decrease (GH1>GH2), with a median 30 vs 33 weeks (P=0.024).
Conclusions: Our data show for the first time that PN have lower median GH levels than HN. GH in PN is associated with ventilation and GA. The latter finding, along with the association between lower GA and increase in GH2 levels could be explained by an incomplete maturity at birth of the somatotropic axis in very PN, with the subsequent GH increase reflecting an extra-uterine maturation of the axis itself.
13 May 2023 - 16 May 2023