Elevated levels of cord blood proinflammatory cytokines (IL‐1β, TNFα, and IL-6) have also been associated with preterm birth, one of the most common causes of neonatal morbidity and mortality (Lyon et al. 2009), as well as chorioamnionitis, brain white matter damage, and chronic lung disease in preterm infants (An et al. 2004; Kaukola et al. 2006). This evidence concerns the gene IL6 and chronic lung disease.