Urinary albumin excretion in diabetic pregnancy

We have analysed the results of urinary albumin excretion in timed overnight urine samples once every two weeks during pregnancy and post-natally in 25 non-diabetic women and 14 women with Type 1 (insulin-dependent) diabetes who were Albustix negative and had urinary albumin excretion less than 15 micrograms.min-1 at conception. Urinary albumin excretion did not vary significantly in the first two trimesters in either group and at 28 weeks was 2.73 micrograms.min-1 (0.32-251.68) (median and range) in the diabetic women and 2.53 micrograms.min-1 (0.90-13.37) in control patients (not significant). During the third trimester urinary albumin excretion increased, and levels were significantly higher in diabetic patients from 36 weeks (9.37 (0.9-31.78) vs 3.52 (0.19-33.74) micrograms.min-1, p less than 0.01) until delivery. In both groups, urinary albumin excretion reached a peak within the week following delivery - diabetic 17.42 micrograms.min-1 (2.03-46.64), control subjects 16.29 micrograms.min-1 (1.53-35.56), but six weeks after delivery, levels were similar to those in early pregnancy. The effect of pregnancy on urinary albumin excretion in these diabetic women would appear to be an exaggeration of the normal pattern, with levels returning to normal post-delivery. It is not possible to know if this has significance for future renal function, but it would be important to investigate this phenomenon in patients who already have raised urinary albumin excretion at conception.