Inhibition of amniotic prostaglandin E release by ampicillin, , ,

OBJECTIVE: The effect of antibiotics in the prevention of preterm labor needs to be further investigated. The aim of this study was to determine the effect of ampicillin on prostaglandin E release from amnion as a possible explanation for its ability to retard preterm labor. STUDY DESIGN: The effect of the β-lactam antibiotic ampicillin on prostaglandin E release from human amnion was tested under basal and stimulated conditions. RESULTS: Ampicillin dose dependently inhibits basal prostaglandin E release from amnion in both static and dynamic conditions. In our experiments, 10-7 mol/L ampicillin (a concentration able to significantly inhibit prostaglandin E output) leaves the microbiologic features of the medium substantially unmodified up to 5 hours of incubation. Moreover, the drug reversibly counteracts the prostaglandin E elevation induced by arachidonic acid or oxytocin. CONCLUSION: This finding (i.e., that ampicillin inhibits prostaglandin E release from amnion) may offer an explanation for a beneficial response to ampicillin therapy in the case of preterm labor even in the absence of bacterial infection. (Am J Obstet Gynecol 1998;178:759-64.)