THE INFLUENCE OF PREGNANCY ON IDDM COMPLICATIONS

OBJECTIVE-Although pregnancy has been associated with an increased pro gression of certain insulin-dependent diabetes mellitus (IDDM) complic ations, particularly retinopathy, both the short- and long-term relati onships between pregnancy and both neuropathy and macrovascular diseas e are poorly documented. This study was conducted to comprehensively e xamine the influence of pregnancy on the development and progression o f IDDM complications. RESEARCH DESIGN AND METHODS-Using the Pittsburgh Epidemiology of Diabetes Complications Study population (childhood-on set IDDM), two nested, pair-matched case-control studies were conducte d. Women who had completed at least one successful pregnancy (n = 80) were matched to women with no history of pregnancy by age, duration of IDDM, race, and marital history. The first nested study (study 1) com pared the prevalences of five IDDM complications between case and cont rol groups. The second nested study (study 2) compared the incidences of the same five complications over an approximate 2-year interval dur ing which the case subjects (n = 30) completed a successful pregnancy. RESULTS-There were no significant differences in the prevalence rates of coronary heart disease, neuropathy, proliferative retinopathy, low er extremity arterial disease, and overt nephropathy by case-control s tatus, while parity did not predict any complication in multiple logis tic analysis (study 1). In study 2, there were small but nonsignifican t differences in incidence rates of overt nephropathy and lower extrem ity arterial disease between the groups, whereas case subjects had alm ost 3 times the incidence rate of proliferative retinopathy (P = 0.58) and 10 times the incidence rate of neuropathy (P < 0.001) as did othe r matched control subjects. In multivariate analysis, parity predicted neuropathy incidence but did not predict the incidence of any other c omplication, including proliferative retinopathy. CONCLUSIONS-Women wi th IDDM who experience a pregnancy may not be at an increased risk of diabetes complications later in life. However, in the short term, preg nancy may accelerate the development of some complications, such as ne uropathy.