Background and aims 
Neurofilaments (Nf) are proteins that form the axonal skeleton. Their quantification in the peripheral blood has been proposed in adults as a biomarker for neuronal injury. In this study we investigated Nf in preterm and term born infants. 
Methods 
This prospective observational study was performed at the University Children’s Hospital Basel. The dataset enclosed infants (n=203) with a median gestational age (GA) of 37.86 (IQR 31.86-39.43) weeks. Blood samples were taken at birth, containing 185 umbilical venous samples, and at day of life (DOL) 3 with 39 venous blood samples. Nf light chain (NfL) was measured with a highly sensitive single molecule array (Simoa) assay.
Results 
The median plasma concentration of NfL at birth was lower (18.20 pg/ml, IQR 12.80-30.80) compared to NfL at DOL 3 (50.90, IQR 41.30–100.10, p<.001). NfL levels at birth significantly correlated with GA (rs=-.27), birth weight (rs=-.40), Apgar-5 min (rs=-.30), delivery mode (rs=.16), preeclampsia (rs=.26), sepsis (rs=.16) and oxygen duration (rs=.33). A significant multiple linear regression was found (F(5,177)= 10.26, p<.001) with an R2 of .23. In particular birth weight (β=-.317), delivery mode (β=.237) and preeclampsia (β=.188) explained the most of the NfL plasma levels. 
Conclusions 
Increased plasma NfL levels after vaginal delivery as compared to caesarean section and in low birth weight infants may indicate increased neuronal injury in these infants.

PLASMA NEURONAL INJURY MARKER NEUROFILAMENT IN THE FIRST DAYS OF LIFE IN PRETERM AND TERM BORN INFANTS