Placental features in preterm infants with periventricular leukomalacia

Evaluation of the placenta provides some important insights into pathophysiologic changes that take place during the prenatal and intrapartum process. We investigated the relationship between placental findings and periventricular leukomalacia (PVL) to obtain a better understanding of its cause.

Thirty-two preterm infants with PVL delivered before 34 weeks' gestation, between 1990 and 1999, were classified into 4 groups according to the onset of brain injury assumed from ultrasonographic presentation and clinical course: 2 Antenatal, 22 Peripartum, 5 Postnatal, and 3 in an unknown time of onset group. We evaluated the gross and histopathologic features of the placentas of each group and compared them with those of a control group matched by birth weight and gestational age in terms of the frequency of major placental findings. Potential confounding factors were controlled in logistic regression analyses.

Gross lesions with disturbance of uteroplacental circulation, including massive retroplacental hematoma, extensive infarction or thrombosis, and marked basal or perivillous fibrin deposition, were observed more frequently in the Antenatal + Peripartum combined subgroup than in the controls (41.7% vs 13.7%). Placentas from the Antenatal + Peripartum subgroup also demonstrated a significantly higher frequency of ischemic changes in villi, based on histopathologic examination, as compared with the control group (54.2% vs 13.7%). These associations remained after adjustment for confounding factors in logistic regression analyses (odds ratio: 4.04, 95% confidence interval: 1.40-11.67; and odds ratio: 7.28, 95% confidence interval: 2.50-21.20; respectively). Frequencies of chorioamnionitis and twin placentation tended to be higher in PVL cases than in the controls, although the differences were not statistically significant (46.9% vs 37.9%, 37.5% vs 20.0%, respectively).

These results suggest that disturbed placental circulation underlies the development of PVL in the majority of cases with prenatal and peripartum brain injury. In chorioamnionitis cases, certain additional factors were suggested in the genesis of PVL. Thus, placental examination is essential for elucidating the pathophysiologic changes leading to PVL in the perinatal process.