[Influence of pregnancy on IgA nephropathy]

In an attempt to clarify the influence of pregnancy on the natural course of IgA nephropathy, the courses of 79 pregnancies occurring in 47 patients with the disease were studied. These resulted in 3 artificial and 10 spontaneous abortions, and two pre-term and 64 full-term deliveries. Fifty four maternity passbooks were analyzed. In 22 pregnancies (40.7%) proteinuria was increased during the third trimester, and in 13 (76.5%) of 17 pregnancies receiving postpartum urinalysis, urinary protein was decreased to the level of the first trimester within one month after delivery. In two of the remaining four patients with a persistent increase in proteinuria, renal biopsy was carried out two months after delivery, revealing focal glomerular sclerotic lesions, in addition to mild mesangial proliferation compatible with IgA nephropathy. These findings indicated that increased urinary protein observed in the two pregnancies might be attributed to a complication of pre-eclamptic focal glomerular sclerosis rather than exacerbation of underlying IgA nephropathy. The glomerular filtration rate (GFR), examined in 27 patients both before and after pregnancy, was decreased in only two patients (7.4%), but these reductions appeared to go with the individual natural course. In 6 (15.0%) of 40 pregnancies, proteinuria was increased within one month after delivery, and one of them was diagnosed both clinically and pathologically as the acute exacerbation of IgA nephropathy. These data suggest that patients with IgA nephropathy might show transient acute exacerbation just after delivery rather than during pregnancy, and that even if such exacerbations occurred, pregnancy might have little influence on the natural course of the disease.