The transplacental passage of prednisone and prednisolone was studied in late pregnancy during a constant infusion of the radioactive steroids to mothers at the time of elective cesarean section. The metabolic clearance rates, conversion ratios, and transfer constants of prednisone and prednisolone of the mothers were compared with those of normal women and women receiving contraceptives. It was found that irrespective of whether 3H-prednisone or 3H-prednisolone was infused, the concentration of 3H-prednisolone in the maternal plasma was significantly higher than that of 3H-prednisone. The maternal 3H-prednisone concentration was similar to the fetal 3H-prednisone concentration. The fetal 3H-prednisone concentration was not significantly different from the fetal 3H-prednisolone concentration which was, however, about 8-to 10-fold less than the maternal 3H-prednisolone concentration. Pregnancy and contraceptive-medication had no effect on the metabolic clearance rates of prednisone or the conversion ratio of prednisone to prednisolone. The metabolic clearance rate of prednisolone was significantly lower than that of prednisone in both pregnant and nonpregnant women.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health