Most people I know that had precipitous births (I only know a couple) were induced in hospital around 39 - 40 weeks for the subsequent births. (skepticalob.com)
Unattended births in studies always includes ALL unattended births, including roadside deliveries, precipitous births, dumpster babies, etc etc.. (ecochildsplay.com)
Lu said that often in a precipitous birth, the baby is coming out so fast that it can do damage to the mother. (abcnews.go.com)