(303) Fetal brain changes in fetuses exposed to threatened preterm labor delivered near or at term

To evaluate whether fetuses exposed to threatened preterm labor (PTL) without intra-amniotic infection or inflammation (IAI) and delivered after 34 weeks show brain structural changes, and whether these persist one month later.

Study Design:
Prospective cohort study including singleton pregnancies with threatened PTL between 23–34 weeks, confirmed absence of IAI via amniocentesis, latency to delivery >4 weeks, and birth beyond 34 weeks. Fetal neurosonography was performed at admission and one month later. A gestational age–matched control group was included. Amniotic fluid levels of neuron-specific enolase, S100B protein, and glial fibrillary acidic protein (GFAP) were compared to biobank samples.

Results:
33 fetuses from the threatened PTL group and 42 controls were analyzed. No differences were found in baseline characteristics, fetal sex, fetal growth or feto-placental Doppler at admission or one month later. 84% of fetuses in the threatened PTL group were born at term. Total corpus callosum area was significantly smaller in the threatened PTL group at admission, mainly affecting the rostral body and anterior midbody. These differences persisted one month later. No other differences in brain biometry, intracranial structures, or cortical development (Silvian fissure, parieto-occipital, cingulate and calcarine sulcus) were observed. Higher amniotic fluid concentrations of neuron-specific enolase, S100B protein, and GFAP supported the neurosonographic findings at admission.

Conclusion:
Fetuses exposed to threatened PTL without IAI and delivered near or at term exhibit persistent corpus callosum reduction, particularly in central regions. Elevated amniotic fluid neuron-specific enolase, S100B, and GFAP levels at admission reinforce early neurosonographic findings. These results align with published data on neurodevelopmental risks in term-born children after PTL and help identify a previously unrecognized high-risk neonatal subgroup that could benefit from early follow-up and preventive interventions.