Clinically detectable nephropathy begins with microalbumin uria-30 to 300 mg/24 hours. his may manifest as early as 5 years after diabetes onset. Macroalbuminuria-more than 300 mg/24 hours-develops in patients destined to have end-stage renal disease. Hypertension almost invariably develops during this period, and renal failure ensues typically in the next 5 to 10 years. The incidence ofovert proteinuria is nearly 30 percent in individuals with type 1 diabetes and ranges from 4 to 20 per cent in those with type 2 diabetes (Reutens, 2013). Regression is common and, presumably from improved glucose control, the incidence ofnephropathy with type 1 diabetes has declined.
Approximately 5 percent of pregnant women with diabetes already have renal involvement. Approximately 40 percent of these will develop preeclampsia (Vidaef, 2008). In those with microproteinuria, this incidence may not be as high (How, 2004). However, mbia and associates (2018) reported that the rates ofpreterm delivery, birthweight <2500 g, and growth restriction were significantly higher in neonates of diabetic women with microproteinuria compared with those of diabetic gravidas without proteinuria.
In general, pregnancy does not appear to worsen diabetic nephropathy. In one prospective study of 43 women with diabetes, diabetic nephropathy did not progress through 12 months after delivery (Young, 2012). Most ofthese women had only mild renal impairment. Conversely, pregnancy in women with moderate-to-severe renal impairment may have accelerated progression of their disease (Vidaef, 2008). As in women with glomerulopathies, hypertension or substantial proteinuria before or during pregnancy is a major predictive factor for ultimate progression to renal failure in women with diabetic nephropathy (Chap. 53, p. 1033).
Diabetic Retinopathy. Retinal vasculopathy is a highly speciic complication ofboth type 1 and type 2 diabetes. In the United States, diabetic retinopathy is the most important cause ofvisual impairment in working-aged adults. he first and most common visible lesions are small microaneurysms followed by blot hemorrhages that form when erythrocytes escape from the aneurysms. hese areas leak serous fluid that creates hard exudates. Such features are termed backgroundor nonprolierative retinopathy. With increasingly severe retinopathy, the abnormal vessels of background eye disease become occluded, leading to retinal ischemia and infarctions that appear as cotton wool exuates. hese are considered preprolerative retinopathy. In response to ischemia, neovascularization begins on the retinal surface and out into the vitreous cavity. Vision is obscured when these vessels bleed. Laser photocoagulation before hemorrhage reduces the rate of visual loss progression and blindness by half. The procedure may be performed during pregnancy when indicated.
Vestgaard and coworkers (2010) reported that almost two thirds of 102 pregnant women with type 1 diabetes examined by 8 weeks' gestation had background retinal changes, proliferative retinopathy, or macular edema. A fourth of these women developed progression of retinopathy in at least one eye during pregnancy. The same group of investigators evaluated 80 type 2 diabetics and identified retinopathy, mostly mild, in 14 percent during early pregnancy. Progression was identiied in only 14 percent (Rasmussen, 2010). This complication is believed to be a rare example of a long-term adverse efect of pregnancy.