Circulating Neurotrophin Levels In The Perinatal Period Of Intrauterine Growth Restricted Fetuses And Neonates At Term

Question: To investigate in intrauterine growth restricted (IUGR) and appropriate for gestational age (AGA) term fetuses and neonates circulating levels of nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4), important for prenatal and postnatal brain development.

Method: Determination by enzyme immunoassays of BDNF, NGF, NT-4 and NT-3 in the plasma of 60 mothers (MS) and their 30 IUGR and 30 appropriate for gestational age (AGA) fullterm fetuses (UC) and neonates on postnatal day 1 (N1) and 4 (N4)

Results: No statistically significant differences were observed between IUGR and AGA MS, UC, N1 and N4 of BDNF, NT-3 and NT-4 levels. However, NGF levels were significantly higher in AGA than IUGR MS (p=0.007), UC (p=0.01), N1 (p=0.043) and N4 (p=0.003) and positively correlated with the infants' centiles and birthweights. IUGR and AGA maternal neurotrophin levels were higher than respective fetal and neonatal levels. Neurotrophin levels showed no correlation with gender or delivery mode in both groups.

Conclusion: Brain sparing effect, caused by fetal hypoxia, could be responsible for similar BDNF, NT-3 and NT-4 levels in IUGR and AGA fullterm fetuses and neonates. As NGF levels positively correlate with infants' customized centile and birthweight, they are higher in AGA. Elevated maternal neurotrophin levels could reflect nervous system maturity. No differentiation in neurotrophin levels among genders might imply their similar neurodevelopment.