Urinary albumin excretion in diabetic pregnancy

Diabetes and the kidney in pregnancy

The prevalence of diabetes in pregnant women is increasing, with 4% of deliveries in the United States occurring in women with pregestational or gestational diabetes. The proteinuria of late pregnancy is exaggerated in women with diabetes. However, diabetic women with preserved renal function before pregnancy appear to have little risk of deterioration of kidney function during pregnancy. Women with impaired renal function before pregnancy may be at risk for permanent decline of renal function during pregnancy, although it is unclear whether this represents the effect of pregnancy or the natural history of their diabetic renal disease. Preeclampsia, which is more common in women with diabetes, may be difficult to diagnose in this group of women. From the currently available literature, there appears to be no negative effect of pregnancy on the long-term progression of diabetic renal disease if renal function is normal and marked proteinuria is absent, but in light of recent findings in which preeclampsia appears to be associated with an increased risk of end-stage renal disease, large cohort studies will be necessary before this question can be definitively answered.

The management of diabetes in pregnancy

The aim of the diabetes specialist is to provide a service to the pregnant diabetic woman so that she will present to her obstetrician with such well-controlled plasma glucose levels that her pregnancy will proceed without any diabetes-related problem, and she will be delivered of a normal baby, of normal size, at the normal full-term gestation, by the normal route. There are some problems in achieving this aim. The exact definition of hyperglycaemia in pregnancy is still a matter of dispute. Screening methods to identify the problem differ widely. Many centres have developed joint diabetes/antenatal clinics, but there are practical problems with such an approach. Pre-pregnancy counselling, and discussion of contraceptive measures is an important task for the diabetologist and requires up-to-date knowledge. Control of plasma glucose requires alteration of insulin doses as pregnancy proceeds. Mothers with retinal, renal or cardiac problems will need special care. The medical problems which develop, and the management of blood glucose during labour and delivery, mean that the diabetes team must be very adjacent to the obstetric service, and a centralised approach offers many advantages. The postpartum state, and the long-term outcome for both mother and baby, remain both an interest and a responsibility for the obstetric physician.

A new model of diabetic pregnancy with genetic hypertension: pregnancy in spontaneously hypertensive rats with neonatal streptozotocin-induced diabetes

OBJECTIVE

We designed this study to develop a new animal model of high-risk pregnancy complicated by hypertension and diabetes mellitus.

STUDY DESIGN

Female spontaneously hypertensive rats were injected intraperitoneally with 75 mg/kg streptozotocin or vehicle as control at 2 days of age. They were mated with untreated male spontaneously hypertensive rats at 4 to 5 months of age.

RESULTS

Hyperglycemia, defined as > 20 mmol/L plasma glucose level, was maintained during pregnancy in streptozotocin-treated spontaneously hypertensive rats, and systolic blood pressure was significantly higher in the streptozotocin-treated group than in controls before delivery (p < 0.01). Furthermore, urinary albumin excretion was significantly increased in the streptozotocin-treated group during and after pregnancy compared with the prepregnant level (p < 0.05), whereas in controls it remained unchanged. The incidence of low birth weight was significantly higher in male neonates from streptozotocin-treated mothers than those from control mothers (p < 0.05).

CONCLUSION

Neonatally streptozotocin-treated spontaneously hypertensive rats may be useful for studying the combined effect of hypertension and diabetes mellitus during pregnancy.

Blood rheology and albumin excretion in diabetic pregnancy

Blood rheology is altered in diabetes and also in non-diabetic pregnant women. The cumulative effect of hyperfiltration, abnormal rheology of pregnancy, and diabetes could be one mechanism contributing to increased intraglomerular pressure and albuminuria in diabetic pregnancy. We conducted a prospective study of 22 Type 1 (insulin-dependent) diabetic patients and 22 non-diabetic women to determine if there was an association of altered blood rheology on glomerular function in diabetic pregnancy. Albumin excretion showed no increment with increasing gestation and was similar in diabetic and non-diabetic women throughout pregnancy (first trimester: 5.0 (3.0-14.0) vs 5.8 (3.7-10.7) mg l-1, p = 0.89; second trimester: 6.0 (5.0-12.0) vs 5.1 (3.6-10.4) mg l-1, p = 0.25; third trimester: 7.5 (3.5-16.0) vs 4.9 (2.9-7.3) mg l-1, p = 0.18). Red cell aggregation index increased in both groups between the first and third trimesters (diabetic patients: mean difference 2.0; Cl: 1.0-2.9, p = 0.003, and control patients: mean difference 2.3, Cl: 1.0-3.5, p = 0.002). Fibrinogen levels were significantly higher between the third and first trimesters in diabetic patients (mean difference 0.7, Cl: 0.2-1.3 g l-1, p = 0.006). Pregnancy, therefore, was associated with increased red cell aggregation, related in part to increased fibrinogen levels but the extent of change was similar in diabetic and nondiabetic women and appeared to have no adverse effect on glomerular function in pregnant insulin-dependent diabetic women.

Abnormal increases in urinary albumin excretion during pregnancy in IDDM women with pre-existing microalbuminuria

We compared urinary albumin excretion during and after pregnancy in 30 insulin-dependent diabetic (IDDM) women with normoalbuminuria and in 12 IDDM women with microalbuminuria (> 15 micrograms.min-1) prior to conception. There was a 6.7-fold increase in the urinary albumin excretion up until the third trimester in the women with pre-existing microalbuminuria, compared with a 3.8-fold increase in the normoalbuminuric women. In both groups of patients the urinary albumin excretion reached a peak during the third trimester with 492 +/- 404 micrograms.min-1 in the microalbuminuric women vs 43 +/- 36 micrograms.min-1 in the normoalbuminuric women (p < 0.0005). Two women from each of the groups developed eclampsia with diastolic blood pressure over 90 mm Hg, mild or moderate oedema and macroproteinuria. Four of the pregnant women with pre-existing microalbuminuria showed a transient nephrotic syndrome (33.3%) with protein excretion over 3 g in 24-h urine samples during the third trimester. In contrast, this was not observed in any of the normoalbuminuric women (p < 0.05). Within 12 weeks after delivery the urinary albumin excretion rates dropped to the pre-conception values in both patient groups. Renal function remained normal during pregnancy in both of the groups, with a physiological increase in creatinine clearance up until the third trimester (26% increase in the normoalbuminuric women vs 22% in the microalbuminuric women). In conclusion, the effect of pregnancy on the urinary albumin excretion in diabetic women with pre-existing microalbuminuria is an exaggeration of the increase of albuminuria in diabetic women with normoalbuminuria; normalization occurs within 12 weeks after delivery in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Managing diabetic patients with nephropathy and other vascular complications

Since the metabolic changes in normal pregnancy are diabetogenic, pregnancy imposes a severe stress on the metabolic milieu of diabetic patients. Moreover, many patients with long-standing diabetes have vascular complications, including retinopathy, renal insufficiency, nephrotic syndrome and hypertension, all representing separate risk factors for optimal fetal development. Recent experience has suggested that maternal hyperglycaemia, and associated fetal hyperinsulinaemia, may represent an important factor in the development of fetal complications. During the past two to three decades the incidence of perinatal deaths in all categories of diabetics has been reduced to a level that approaches the rate in healthy gravidas when severe congenital anomalies are excluded. Fetal and neonatal morbidity have also been reduced, although rates of congenital anomalies, hydramnios and respiratory distress syndrome remain high. Although the morbidity associated with oedema formation and hypertension is elevated, with meticulous management of patients with diabetic nephropathy, especially in the absence of severe renal insufficiency and/or severe hypertension, pregnancy performance and outcome can be similar to that of other insulin-dependent diabetic patients.

The effect of pregnancy on renal function: physiology and pathophysiology

Marked changes in renal function occur with pregnancy. We present a summary of these changes in this review and give insight into possible mechanisms if they are known. Controversies exist regarding the therapy of pregnancy-induced hypertension and asymptomatic and recurrent bacteriuria. The current views on these topics are given. Specific renal diseases are summarized, including transplantation, and optimum management strategies and maternal and fetal prognosis during pregnancy are given.