Cranial ultrasound abnormalities identified at birth: Their relationship to perinatal risk and neurobehavioral outcome

Objectives. Minor cranial ultrasound abnormalities, such as mild ventricula r enlargement, choroid plexus cysts, and subependymal cysts, have been iden tified in 3% to 5% of the newborn population. Although clinicians generally consider these abnormalities to be insignificant for the outcome of the ne wborn, few convincing data have been published to support this optimism. Th e objectives of this study were to identify potential risk factors associat ed with the identification of cranial ultrasound abnormalities at birth and to determine if the abnormalities were related to neurobehavioral sequelae in the newborn. Methods. Three hundred eight women were enrolled in this prospective, longi tudinal maternal-infant health and development study either at the time the y entered the public health care system for prenatal care or at delivery if they had no prenatal care. Each woman participated in an in-depth psychoso cial interview at the end of each trimester of pregnancy. Retrospective cha rt review by experienced medical personnel was used to compile data for the Hobel perinatal risk score for each study participant after delivery. Offs pring underwent cranial ultrasound evaluation, the Amiel-Tison Neurologic A ssessment, and the Brazelton Neonatal Behavioral Assessment Scale within 96 hours of birth by experienced examiners blinded to any maternal-infant his tory. Results. Of the 308 women originally enrolled in the study, 301 delivered l iving infants. Of these, 266 infants (88%) underwent a cranial ultrasound e valuation and are the subject of this article. For the purposes of the curr ent study, infants were divided into those with normal (n = 239) and those with abnormal (n = 27) ultrasound results. Abnormal ultrasound results incl uded the following lesions: subependymal cyst (n = 13); mild ventricular en largement (n = 6); choroid plexus cysts (n = 3); a combination of cysts and increased ventricular size (n = 2); a 7-mm midline cyst in the superior po sterior portion of the third ventricle (n = 1); subependymal hemorrhage and ventricular enlargement (n = 1); and increased ventricular size, subependy mal hemorrhage and cysts, and two small, right thalamic calcifications (n = 1). There were no significant differences between those with an abnormal u ltrasound and those with a normal ultrasound for birth weight, length, gest ational age, rate of prematurity, frequency of nulliparity, or frequency of small for gestational age infants. However, infants with an abnormal ultra sound had a significantly smaller mean head circumference than those with a normal ultrasound (34.5 +/- 1.9 cm vs 33.7 +/- 1.9 cm). The infants with a n abnormal ultrasound had a higher median prenatal (50 vs 45), neonatal (14 vs 8), and total (94 vs 77) Hobel risk score but not a higher labor-delive ry score. There were no significant differences when these groups were comp ared on additional risk factors not included in the Hobel scoring system su ch as race and socioeconomic status. In addition, mothers who used a greate r number of drugs during the first trimester of pregnancy were more likely to have an infant with an abnormal ultrasound at birth such that the probab ility of having an abnormal ultrasound rose to 22% by the time the pregnant women were using four drugs. Neurologic examinations revealed no differenc es between the infants with normal and abnormal ultrasounds. There were als o no group differences for five of the seven Brazelton cluster scores, the excitable or depressed clusters, or eight of the nine qualifier scores. How ever, infants with abnormal ultrasounds performed significantly better on t he habituation (7.3 +/- 0.8 vs 6.6 +/- 1.5) and autonomic regulation (6.5 /- 0.8 vs 6.0 +/- 1.0) clusters but more poorly on the cost of attention qu alifier score (4.9 +/- 1.2 vs 5.5 +/- 1.2) on the Brazelton Neonatal Behavi oral Assessment Scale. Conclusion. Infants with an abnormal cranial ultrasound at birth had higher perinatal risk scores. Additionally, we conclude that the abnormalities id entified on cranial ultrasound within the first 96 hours of life were most likely benign with no clinical significance in the immediate neonatal perio d. However, because of the finding of several subtle differences in behavio r, follow-up beyond the neonatal period would be advisable to determine if any late-onset abnormalities occur.