Some of the more frequent causes of the nephrotic syndrome are minimal change disease (10-15 percent), focal segmental glomerulosclerosis (35 percent), membranous glomerulonephritis (30 percent), and diabetic nephropathy. In most cases, renal biopsy will disclose microscopic abnormalities that may help direct treatment (Chen, 2015; Lo, 2014). Edema is problematic, especially during pregnancy. Normal amounts of dietary protein of high biological value are encouraged. The incidence of thromboembolism is increased and varies with the severity of hypertension, proteinuria, and renal insuiciency (Stratta, 2006). Although both arterial and venous thromboses may develop, renal vein thrombosis is particularly worrisome. he value, if any, of prophylactic anticoagulation is unclear. Some cases of nephrosis from primary glomerular disease respond to glucocorticosteroids and other immunosuppressants or cytotoxic drug therapy. In most of those cases caused by infection or drugs, proteinuria recedes when the underlying cause is corrected.
Maternal and perinatal outcomes in women with the nephrotic syndromes depend on its underlying cause and severity. Whenever possible, these should be ascertained, and renal biopsy may
FIGURE 53-3 Massive vulvar edema in a pregnant woman with the nephrotic syndrome due to secondary syphilis. (Used with permission from Dr. George Wendel, Jr.) be indicated to determine if the etiology will respond to treat ment. Half of women with nephrotic-range proteinuria will have a rise in daily protein excretion as pregnancy progresses (Packham, 1989). In women with nephrosis cared for at Park land Hospital, we reported that two thirds had protein excre tion that exceeded 3 g/d (Stettler, 1992). At the same time, however, if these women had only mild degrees of renal dys function, they had normally augmented CFR across pregnancy (Cunningham, 1990).
Management of edema during pregnancy can be particularly challenging as it is intensiied by normally increasing hydrostatic pressure in the lower extremities. In some women, massive vulvar edema may develop. An example of massive vulvar edema associated with the nephrotic syndrome caused by secondary syphilis is shown in Figure 53-3. Another major problem is that up to half of these women have chronic hypertension that may require treatment. In these, as well as in previously normotensive women, preeclampsia is common and often develops early in pregnancy.
Most women with nephrotic syndromes who do not have severe hypertension or renal insuiciency will have successful pregnancy outcomes. Conversely, if there is renal insuiciency, moderate to severe hypertension, or both, the prognosis is much worse. In a group of such women with 65 pregnancies cared for at Parkland Hospital, complications were frequent (Stettler, 1992). Protein excretion during pregnancy averaged 4 gl d, and a third of the women had classic nephrotic syndrome. here was some degree of renal insuiciency in 75 percent, chronic hypertension in 40 percent, and persistent anemia in 25 percent. Importantly, preeclampsia developed in 60 percent, and 45 percent had preterm deliveries. Even so, after excluding abortions, 53 of 57 neonates were born alive. In another series, fetal-growth restriction was noted in a third of pregnancies in afected women (Stratta, 2006).