PERSISTANCE OF AMPICILLIN IN THE INTRAUTERINE CONTENT FOLLOWING SINGLE AND MULTIPLE DOSES TO PREGNANT WOMEN

Cord plasma, and amniotic fluid (AF), as well as maternal plasma from women who had been given ampicillin in single or multiple doses prior to delivery were assayed for levels of the antibiotic. If medication had been discontinued two days prior to delivery or less, ampicillin could still be demonstrated in AF, where it remained demonstrable longer than in cord plasma. Ampicillin, when given during pregnancy, crosses the placenta, enters the fetal circulation, and is excreted by the fetal kidneys into the AF. The results of the present study indicate that as medication is continued, the level of ampicillin in AF rises through continuous renal excretion by the fetus. Once medication is discontinued, ampicillin is slowly cleared from the AF mainly through absorption from AF to fetal circulation and further passage to maternal circulation.