[Experimental and clinical study on chorioamnionitis as a cause of preterm labor]

I performed the following studies to confirm the recent recognition of chorioamnionitis as a cause of preterm labor and to evaluate the effect of antibiotics in the treatment of this disease. 1. Models of chorioamnionitis were prepared using prepartal rabbits by directly inoculating bacteria at various concentrations into the amniotic cavity. Preterm deliveries occurred 2-3 days after inoculation in most of the animals when given no antibiotic, but not when treated with antibiotic after inoculation at 10(3) cells/ml or less. 2. These results were confirmed pathologically and bacteriologically in animals sacrificed 3 days after inoculation. 3. When morphologies of the placenta and umbilical cord obtained at various gestational weeks were examined, it was revealed that patients developing preterm labor or PROM before 33 gestational weeks had significantly severer inflammation than did others. 4. While I have undertaken antibiotic therapy in PROM patients since April, 1985, it has been noted that the length of time between its diagnosis and delivery can be prolonged by antibiotic therapy and that such treatment can also prevent neonatal infection. Thus it is concluded that infection is a cause of preterm labor and should therefore be treated with antibiotics to prevent preterm labor without hesitation.