Problem: Birth-related factors and neonatal treatments could affect the maturation of immune system and thus have lasting effects on immune responses. We investigated the effect of obstetric factors other than being born by cesarean section on immune responses later in life.

Method of study: Regulatory, inflammatory, TH1 and TH2 cytokines, and a chemokine were analyzed in unstimulated and Toll-like receptors (TLRs) 2-, 3-, and 4-stimulated PBMCs of teenagers born by cesarean delivery (CD; N=79). Data on obstetric factors were collected from patient data archives.

Results: Advanced cervical dilatation at the time of CD associated with higher unstimulated production of cytokines compared to adolescents who were delivered before the onset of labor. Neonatal intensive care treatment associated with lower unstimulated production of cytokines. Similar associations were found following TLR stimulations.

Conclusion: The lack of natural processes of delivery and neonatal intensive care treatment might lead to long-lasting impairment of immune responses.