[Incidence of congenital hydrocephalus and the role of the prenatal diagnosis].

OBJECTIVE To investigate the increasing incidence of hydrocephaly at the Hospital CAISM-UNICAMP and to identify its probable causes. METHODS All children with hydrocephaly delivered at CAISM from September 1987 to December 1998 were studied. Those children presenting hydrocephaly due to neural tube defects were excluded. Data were collected from medical records of the Perinatal Genetics Sector (CAISM). Hydrocephaly incidence and statistical trend were analyzed using the Cochran-Armitage test. RESULTS During the study, 111 infants with hydrocephaly (3.16/1,000 births) were identified. The annual incidence shows a significant increasing trend of hydrocephaly cases (p = 0.001). This phenomenon has been more evident since 1992. After classifying hydrocephaly in four subgroups (i.e., isolated hydrocephaly, hydrocephaly associated with congenital infection, syndromic hydrocephaly, and hydrocephaly associated with multiple defects), only isolated hydrocephaly cases show a significant increasing trend (p = 0.001). Ultrasonographic prenatal diagnosis was performed in most hydrocephaly cases (85%, 94/111). In this group, 66% of the cases were transferred to CAISM because of the diagnosis of hydrocephaly. CONCLUSION The present study strongly suggests that the increasing trend of hydrocephaly at CAISM might be related to the ultrasonography prenatal diagnosis. The subsequent referral of these cases to CAISM is due to the fact that this center is located in a Reference Hospital. Finally, among the hydrocephaly clinic groups, the increasing trend is specially observed in the etiological heterogeneous group of isolated hydrocephaly.