Transfer ofCephaloridine fromMother toFetus

Wherethere isriskofintrauterine infection in pregnancy anyantibiotic administered tothemother mustcross theplacenta inorder tobeeffective in thefetus. Theconcentration inthefetus mustbe sufficient toinhibit thegrowthofthecommonly encountered pathogenic organisms. Materials andMethod Thirty-one women whosemembraneshad been ruptured for48hours ormoreandinwhomdelivery was imminent weregiven cephaloridine ('Ceporin'), abroad spectrum semisynthetic antibiotic, indosesof1 g. 12-hourly byintramuscular injection. At delivery a venous blood sample wastaken fromthemother andthe cord, andafurther sample fromthebabyoncesometime during the36hoursafter birth. Serawereseparated andstored at-20°C.until theycouldbeassayed for cephaloridine. Concentrations ofcephaloridine inthe serawereestimated bymicrobiological assay(M.J. Marshall, 1966, personal communication). Results Theconcentrations ofcephaloridine foundin30 maternal and31cordseraandintheserafrom21 newborn infants areshownintheFigure, which givesthemeanlevels obtained ineach2-hour period after injection. The levels inmaternal serumafter injections of1g.followed theexpected pattern (Apicella, Perkins, and Saslaw, 1966; Kislak, Steinhauer, andFinland, 1966).Cephaloridine readily crossed theplacenta andwasfoundin highconcentrations inthecordandinfant sera. Thoughpeaklevels inthebabywerelowerthan thoseinthemother, thedecline wasslower, and measurable levels persisted forupto22hoursafter thelast pre-delivery dose.Cephaloridine concentrations inthebabies werehigher thanthose inthe motherfromabout5hours after aninjection ofthe antibiotic. On theoccasions whenalowlevel of cephaloridine wasfoundincordserumitaccompanied alowlevel inthematernal serum.