Transient hypothyroxinemia of prematurity and histological chorioamnionitis.
BACKGROUND
Transient hypothyroxinaemia of prematurity (THOP) is a common condition of preterm infants whose causes remain unclear. We tested the hypothesis that THOP is associated with histological chorioamnionitis (HCA).


METHODS
Whole blood T4 and TSH concentrations on day 4 and at 40 weeks' postmenstrual age (rtx-T4 and rtx-TSH), placental histology and illness severity were prospectively evaluated in 155 very low birth weight (VLBW) infants.


RESULTS
HCA-positive infants showed significantly decreased blood total T4 concentrations on day 4, as compared to the HCA-negative population (P<0.0001), along with comparable TSH, rtx-T4, and rtx-TSH blood concentrations. None of the infants showed evidence of hypothyroidism during the study. A total T4 < or = 4.4 microg/dL on postnatal day 4 identified HCA-positive newborns with 90.8%, sensitivity, 94.7%, specificity, 96.7% positive predictive and 85.7% negative predictive values. HCA (OR: 32.19; 95% CI: 8.95-115.64), birth weight < or = 880 g (OR: 4.1; 1.15-14.64), and RDS (OR: 3.71, 95% CI: 1.13-12.25) were independently associated with evidence of hypothyroxinaemia on day 4.


CONCLUSIONS
Our findings indicate a previously un-recognized relationship between HCA and THOP, hence suggesting a predominant role for a fetal systemic inflammatory response syndrome in the pathogenesis of THOP.
De Felice
Claudio
C
Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, Italy.
Bagnoli
Franco
F
Toti
Paolo
P
Musarò
Maria Antonietta
MA
Peruzzi
Luana
L
Paffetti
Patrizia
P
Latini
Giuseppe
G
D000367:Age Factors; D002821:Chorioamnionitis / Q000097:blood* / Q000473:pathology; D003409:Congenital Hypothyroidism / Q000097:blood / Q000175:diagnosis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D019102:Infant, Very Low Birth Weight; D008297:Male; D015997:Neonatal Screening; D011247:Pregnancy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000172:deficiency*
D013972:Thyrotropin; D013974:Thyroxine