Risk Factors of Cerebral Palsy in Preterm Infants

OBJECTIVES: To investigate the outcome of preterm infants and the prevalence of cerebral palsy and to examine the relevance between clinical risk factors, ultrasonographic abnormalities and the development of cerebral palsy. METHODS: From January, 1993, to December, 1994, we selected and followed up 437 cases of survived preterm infants born in Seoul National University Hospital. Clinical risk factors such as gestational age, birth weight, maternal complications, birth asphyxia, and neonatal sepsis were evaluated. Sequential ultrasonographic observations were done at the interval of 7 or 10 days. Ultrasonographic abnormalities could be classified into periventricular echodensity, periventricular leukomalacia (PVL) including cystic PVL, intraventricular hemorrhage, ventriculomegaly and brain atrophy. Diagnosis of the cerebral palsy was confirmed after the follow up more than 2 years after birth, and the correlations of ultrasongraphic abnormalities with clinical types and severities of cerebral palsy were analyzed. RESULTS: Twenty one cases (4.8%) among survived infants were diagnosed as a cerebral palsy. The prevalence of cerebral palsy was 20% in infants with less than 32 weeks of gestation, and 1.4% after 34 weeks. The prevalence of cerebral palsy was 12% in infants with less than 2000 g of birth weight, while, 0.4% in more than 2000 g of birth weight. Mother's age, primiparaty, and history of abortion did not influence the prevalence of cerebral palsy, but preterm labor, preterm rupture of membrane, severe birth asphyxia, neonatal sepsis, and respiratory distress syndrome were significantly relevant to the increased prevalence of cerebral palsy. Fifty six percents (18/32) of PVL (100% of cystic PVL) and 53% (7/13) of third grade IVH progressed to a cerebral palsy. Without PVL, third grade IVH had no explicit correlation with a cerebral palsy. Multiple logistic regression analysis of clinical risk factors and ultrasonographic abnormalities revealed that PVL is a determinant and independent risk to the cerebral palsy. Most cases turned out a spastic diplegia. The cases with cystic lesions especially showed the worse clinical outcomes. CONCLUSION: Four point eight percents of survived preterm infants developed a cerebral palsy. The existence of PVL was the most important risk factor among the perinatal problems and ultrasonographic abnormalities.

Periventricular Leukomalacia and Cerebral Palsy in Preterm Infants

As the survival rate of preterm infants increasing, much perinatologic concern has been paid to the possibility of their getting into cerebral palsy. The purpose of this study is to determine the relationship between the early periventricular abnormalities and the incidence of cerebral palsy among preterm infants, and then to estimate the value of periventricular leukomalacia(PVL) as the prognostic factor by verifying the clinicopathological correlation of it with cerebral palsy. We have selected 174 cases with periventricular abnormality in early ultrasonographic findings among the survival preterm infants. 163 of them were followed up successfully to verify the incidence of cerebral palsy. Sequential ultrasonographic observations had been made at the interval of 7 or 10 days. Periventricular abnormalities could be classified into three types, which consist of the PVL(including cystic PVL), suspicious PVL, and periventricular echodensity without tissue loss. Associated lesions such as intraventricular hemorrhage, ventriculomegaly, brain atrophy were evaluated. Diagnosis of cerebral palsy was confirmed after following up more than 2 years of age, and the correlations of periventricular abnormalities with the clinical type and severity of cerebral palsy were analyzed. The 24.5% (40/163) of our samples revealed periventricular leukomalacia and the 17.8% (29/163) of them were diagnosed as cerebral palsy. The 65% (26/40) of preterm infants with definite PVL were cerebral palsy and their relative risk ratio for cerebral palsy is 26.7. Without PVL, there were no explicit correlations between cerebral palsy and associated abnormalities. Most cases with cerebral palsy turned out to be the spastic diplegia. In the cases with cystic lesions especially, the clinical outcome appear to be more severe. We've reached the point that the presence of PVL in preterm infants had a strong correlation with the development of cerebral palsy. Moreover, the association with cystic lesions is not only a strong correlation with cerebral palsy, but also a poor prognostic value for functional outcome.