Universal cranial ultrasound screening in preterm infants with gestational age 33-36 weeks. A retrospective analysis of 724 newborns.

BACKGROUND: Cranial ultrasonography is a useful tool to detect intracranial lesions in premature neonates at risk. Our primary aim was to determine the number of patients with abnormal cranial ultrasonography. Secondary aims were to evaluate the usefulness of universal cranial ultrasonography screening in moderately preterm infants.

METHODS: All infants born from 2007 to 2012 at the University Hospital of Ferrara (Italy), with gestational age of 33-36 weeks, were included in the study. Cranial ultrasonography findings were retrospectively classified into nonsignificant and significant.

RESULTS: All the 724 babies born were screened. Intracranial lesions were in 13% of neonates (3.7% at 36 weeks to 27.1% at 33 weeks of gestational age). Babies born at 33-34 weeks of gestational age were four times more likely to have an abnormal cranial ultrasonography than those at 35-36 weeks. Statistical analysis revealed no association between cranial ultrasonography abnormalities and being small for gestational age or mode of delivery. A significant association was present between the presence of head circumference less than the third percentile, the need for ventilation or surfactant, low Apgar index at fifth minute, and neurological abnormalities. The presence of at least one considered risk factor increases the probability of cranial ultrasonography abnormalities twice in infants born at 33-34 weeks and 15 times in born at 35-36 weeks.

CONCLUSIONS: A considerable number of infants born between 33 and 36 weeks have cranial ultrasonography abnormalities. We suggest that screening should be performed or at least that a uniform protocol should be developed for the early detection of all significant cranial ultrasonography abnormalities.