Increased serum aldosterone in diabetic pregnancy.

Serum levels of aldosterone and cortisol were measured by radioimmunoassay in 15 patients with gestational diabetes, in 18 patients with Type 1 (insulin-dependent) diabetes, in 36 pregnant control women and in 10 non-pregnant control women. All subjects, on habitual sodium and potassium intake, were sampled in a supine position at 09.00 hours. Pregnant women were examined twice, during gestational week 32-34 and at delivery. Serum levels of aldosterone and cortisol were also measured in the umbilical cord blood of newborn babies of these diabetic and non-diabetic mothers. Serum levels of aldosterone in both gestational and Type 1 pregnant diabetic women were found to be consistently above the reference values of non-diabetic pregnant women. Abnormal serum levels of aldosterone were also observed in newborn infants of diabetic mothers. In contrast, serum levels of cortisol were not increased.