Background: Cystic periventricular leukomalacia (cPVL) is a strong indicator of subsequent motor and developmental impairments in premature infants. There is a paucity of publications on biomarkers of cPVL.

Objectives: To determine C-reactive protein (CRP) levels during the first week of life of preterm infants who later developed cPVL and to identify the association between CRP levels with perinatal factors.

Methods: We retrospectively included infants ≤ 32 weeks gestation and/or birth weights ≤ 1500 grams; 17 with a cranial ultrasound diagnosis of cPVL and 54 with normal ultrasounds. Serum CRP levels were measured during days 1-7 (CRP^1–7d) of life and subdivided into two timing groups: days 1–3 (CRP^1–3d) and days 4-7 (CRP^4–7d).

Results: The cPVL group had significantly higher mean CRP^4–7d levels compared to controls (12.75 ± 21.2 vs. 2.23 ± 3.1, respectively, P = 0.03), while CRP^1–3d levels were similar. CRP^1–7d levels were significantly correlated with maximal fraction of inspired oxygen during the first 12 hours of life (FiO₂-12h, r = 0.51, P < 0.001]. Additional risk factors were not associated with CRP levels.

Conclusions: Our finding of elevated CRP^4-7d levels and later development of cPVL supports earlier studies on the involvement of inflammation in the pathogenesis of cPVL. Whether CRP could serve as a biomarker of cPVL and its correlation with outcomes, awaits further trials. Furthermore, the correlation between FiO₂-12h and CRP^1–7d levels suggest that hypoxia and/or hyperoxia may serve as a trigger in the activation of inflammation during the first days of life of preterm infants