Impact of risk factors other than prematurity on periventricular leukomalacia. A population-based matched case control study.

OBJECTIVE: Periventricular leukomalacia (PVL) is a neonatal brain white matter injury associated with development of cerebral palsy, intellectual impairment, and visual disturbances. PVL is more common in premature neonates. Our objective was to examine the impact of several potential risk factors other than prematurity on the incidence of PVL.

STUDY DESIGN: A case-control study based on the Slovenian National Perinatal Information System data for the period 2002-2011. All singleton and twin pregnancies delivered at ≥22 weeks' in Slovenia during the study period were included. Cases were pregnancies with PVL in at least one neonate. For each pregnancy in the case cohort, three pregnancies matched by gestational age and plurality were selected. Chi-square test was used to examine the associations between PVL and several potential risk factors: maternal age, pre-pregnancy body-mass-index, preexisting diabetes, gestational diabetes, pregnancy after in-vitro-fertilization, severe preeclampsia, vaginal delivery, no steroid therapy prior to delivery, small for gestational age, and fetal-inflammatory-response-syndrome. P<0.05 was considered statistically significant.

RESULTS: One lakh ninety one thousand and eighty three singleton and 3377 twin pregnancies delivered at ≥22 weeks' in Slovenia during the study period. PVL was diagnosed in 86 singletons (0.045%) and 25 twins (0.74%). In all twin pregnancy cases only one twin was diagnosed with PVL. 258 singleton and 75 twin controls were matched to the 86 singleton and 25 twin cases. Of all risk factors studied, only maternal obesity and chorioamnionitis were significantly associated with PVL.

CONCLUSION: Maternal obesity and chorioamnionitis increase the risk of PVL beyond that expected solely from prematurity.