Impaired cardiac adjustment to pregnancy in type I diabetes.

To assess the adaptation of the heart of diabetic subjects in the natural volume overload state of pregnancy, echocardiography was performed during each trimester and postpartum in 17 women with insulin-dependent diabetes mellitus (IDDM) and in 11 healthy women. The mean duration of diabetes was 14 yr and signs of microvascular complications were detected in 6 patients. The diabetic women had slightly smaller left ventricles than the control women already in the basal state (postpartum), and the pregnancy-induced increase in left ventricular size and stroke volume was less in the diabetic than in the control women. The heart rate rise also tended to be less in the diabetic women, resulting in a markedly smaller increase in cardiac output in this group (1.3 vs. 3.4 L/min, P less than .01). Left ventricular systolic function, wall thicknesses, or left atrial size did not differ between the groups at any point in the study. Minor collections of pericardial fluid were observed in 14 (76%) diabetic women and in 5 (45%) control women during the second and/or third trimester, but only 2 diabetic women had classic pericardial effusions. In conclusion, the normal hemodynamic adjustments to pregnancy seem to be impaired in women with IDDM. Preclinical diabetic cardiomyopathy and autonomic neuropathy may be involved in the observed alterations.