Routine lumbar punctures in the newborn--are they justified?

The records of 62,107 neonates cared for at three neonatal referral units between 1979 and 1985 were analysed with regard to the number of lumbar punctures (LP) performed and the results obtained. The mean perinatal mortality rate was 9.3/1000 live births and the neonatal mortality rate was 5.9/1000. The units were comparible in this respect. Two hundred and sixty three (0.4%) babies weighed less than 1.0 kg at birth and 510 (0.8%) babies weighed 1.0-1.5 kg. A total of 1554 LPs were performed on 1084 babies, 1.7% of the whole population. Seventeen babies were diagnosed as having meningitis following CSF examination; 5 weighed less than 1.5 kg (VLBW) (incidence of meningitis 6.5/1000 births) and 12 weighed more than 1.5 kg (incidence 0.2/1000 live births). An LP was performed on 44% of VLBW babies and 1.2% of babies weighing more than 1.5 kg. In both groups approximately 1.5% of CSF samples were positive. Eight of the 17 positive results were obtained during the first 3 postnatal days. Only one VLBW baby had meningitis on the 1st day of life (1.3/1000). In view of the low incidence of meningitis and the risk factors associated with an LP it is questionable whether this procedure should be a routine investigation in the VLBW newborn.