Placental transfer of cefmenoxime in late pregnancy.

The broad spectrum of activity and the beta-lactamase stability of cefmenoxime provide this new cephalosporin a possible efficacy in the treatment of obstetrical infections. This study was designed to evaluate the placental transfer of cefmenoxime. The study group consisted of 21 pregnant women undergoing a cesarian section. After a single intramuscular injection of 1 g of cefmenoxime, samples of maternal blood and amniotic fluid were taken 30 min before and at delivery; the same samples as well as umbilical cord blood samples were also taken 1, 2, 3 or 4 h after the injection, in order to evaluate the kinetics of the drug. The antibiotic assay was carried out by microbiological procedure. The results of the study showed (1) a peak level of 16 micrograms/ml in maternal serum, with a slow decrease and a residual value of 3 micrograms/ml at 4 h; (2) increasing levels of the drug in cord blood, with a peak value of 4.8 micrograms/ml; (3) a progressive diffusion of cefmenoxime in amniotic fluid, reaching the highest value of 4.7 micrograms/ml at 3 h, and (4) parallel kinetics of the drug in amniotic fluid and in cord blood. On the whole, this study showed a significant placental transfer of cefmenoxime, achieving therapeutic concentrations required against microorganisms responsible for obstetrical infections.