Twenty-three pregnant subjects have been studied by means of the oral glucose tolerance test to compare the effect of hydrocortisone and prednisolone on blood glucose levels. In four patients an additional GTT, using twice the standard dose of prednisolone before the glucose load, was compared with the previous tests. In another two patients, the effect on glucose excretion was compared when hydrocortisone or prednisolone was administered.
The results suggest a potentiation in the biologic effect of hydrocortisone during pregnancy, but not with prednisolone as has been reported in nonpregnant subjects receiving estrogens. It appeared that to duplicate the glucocorticoid effect of hydrocortisone, a ratio of potency of prednisolone to hydrocortisone in pregnancy may be 2:1 rather than the 4:1 ratio observed during the nonpregnant state.
Prednisolone instead of hydrocortisone, as the provocative agent for the detection of subclinical diabetes in pregnancy, may be useful, or perhaps a smaller dose of hydrocortisone should be employed than is required for the nonpregnant subjects.