Transplacental passage of cefazolin in the first trimester of pregnancy.

The transfer of cefazolin, an antibiotic compound of the cefalosporin group, through the placental barrier was investigated in the first trimester of pregnancy. All cases were chosen from among women admitted for therapeutic abortion. The test group comprised 70 women, while there were 30 in the control group. The bacteriostatic activity was examined in the amniotic fluid, obtained by the vaginal route as well as the maternal blood, following the i.m. injection of 500 mg cefazolin. Our results indicate that the antibiotic cefazolin crosses the placental barrier, even during the first trimester of pregnancy. However, the concentrations obtained were considerably lower than those observed in the 2nd and 3rd trimesters.