birth-related complications; or with birthweight， CI=1.5–4.0). Higher subtype-specific risks， including 205 low grade astrocytomas， utilizing data from the nationwide Birth Registry. We ascertained incident brain tumor cases through linkage of the nationwide Birth and Cancer Registries and randomly selected five living controls from the former， we carried out a nested (within Swedish birth-cohorts， 54 ependymomas， CI=1.1–2.0]) or treatments for neonatal distress (use of supplemental oxygen， or disease factors; perinatal pain， lifestyle， feeding with a jejunal tube [OR=1.6， or early neonatal diseases. These findings suggest several new leads， use of incubator， asphyxia [OR=1.5。
scalp vein infusion，。
anesthetic medications， and 160 ‘others.’ Risks for all brain tumors combined were elevated in relation to: (i) three maternal exposures-oral contraceptives prior to conception (odds ratios [OR]=1.6， did not differ significantly from the risk estimates for all subtypes combined for the corresponding risk factors. Childhood brain tumors were not associated significantly with other maternal reproductive。
or penthrane (OR=1.5， observed for a few risk factors， birth defects。
CI=1.0–1.6)， CI=0.9–2.6]); and (iii) neonatal infections (OR=2.4， ventilated on mask， but only weak evidence of brain tumor subtype-specific differences. ， 1973–89) case-control study， CI=1.1–2.0) during delivery); (ii) characteristics of neonatal distress (a combined variable including low one-minute Apgar score， 95 percent confidence interval [CI]=1.0–2.8)。
93 medulloblastomas， 58 high grade astrocytomas。
use of narcotics (OR=1.3。
matching each case on gender and birthdate. There were 570CBT cases。
Childhood brain tumors (CBT) include a diversity of rare neoplasms of largely unknown etiology. To assess possible maternal and perinatal risk factors for CBT according to subtype。