A Consideration of the Results of Albuminuria occurring during Pregnancy, with special reference to the relationship between Pregnancy Kidney and Chronic Nephritis.
The frequency with which albuminuria of pregnancy recurs with subsequent pregnancies is very much greater than is usually stated. In a series of twenty-eight cases it recurred in 68 per cent.Its significance lies in that it points to permanent renal damage.A patient with recurrent albuminuria of pregnancy usually manifests signs and symptoms of "pregnancy kidney" rather than of chronic nephritis. This is accounted for by breaking away from the practice of trying to fit into distinct pathological groups, cases which are really varying mixtures of two pathologies. Recurrent albuminuria of pregnancy is really a transitory pregnancy kidney occurring in a patient who is suffering from a permanent chronic nephritis.Evidence is brought forward to show that chronic nephritis may arise de novo as a sequel to pregnancy kidney. The frequency with which this permanent damage can be demonstrated in previously healthy women depends largely upon the delicacy of the tests for estimating renal function. The most delicate test is a subsequent pregnancy; and where this is available, we find permanent renal damage in about 57 per cent. If such advanced changes as persistent albuminuria, cardiac hypertrophy, etc., are taken as evidence of chronic nephritis, we find it in only 14 per cent.When pregnancy occurs in a patient already suffering from obvious chronic renal disease, the superimposed pregnancy kidney (which always occurs to a greater or less extent) causes an increase in the permanent renal damage. These cases are uncommon, but always serious, and, on account of the danger to which the mother is exposed, pregnancy should invariably be terminated as soon as possible.It is never possible to say that there is no danger to the mother when albuminuria occurs during pregnancy; and the term "functional albuminuria of pregnancy" should be abolished, being misleading to the clinician, and meaningless to the pathologist.The remaining cases of albuminuria during pregnancy are due to pregnancy kidney. It is shown that they run two main risks. The risk of eclampsia (except in fulminating cases) can be avoided by proper treatment and timely termination of pregnancy. The risk of chronic nephritis occurring as a direct result of pregnancy is, however, not sufficiently recognized, and in consequence, steps are not usually taken to avoid what is actually quite a common sequel. If a patient with albuminuria is treated carefully over a long period, and induction of labour is performed only just soon enough to avoid eclampsia, there is a tendency to regard such treatment as an obstetric triumph made possible by the great clinical acumen of the obstetrician. Actually it is often a grave obstetric blunder, in that, as a result of the prolonged albuminuria, an incurable chronic nephritis may develop. Once this danger has been recognized we may turn our attention to the possibility of avoiding it-and some indication is given as to how cases in which permanent renal damage is likely to arise, may be recognized, so that labour may be induced as a prophylactic (rather than a therapeutic) measure against chronic nephritis. It is also shown that it is unwise to jeopardize the mother for the sake of what may in these cases quite likely be a macerated foetus.