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Liu Z, Cui Z, He Y, Zhang Y, Wang F, Wang X, Meng L, Cheng X, Liu G, Zhao M: Membranous Nephropathy in Pregnancy. American Journal of Nephrology DOI 10.1159/000505175
The information concerning the impact of primary membranous nephropathy (MN) on the mother and fetus in pregnancy is scanty. Liu et al. have at least partially filled this gap with a retrospective and detailed analysis of 27 pregnancies complicated by primary MN. These subjects had primary MN diagnosed before pregnancy (n = 11), or were diagnosed by a renal biopsy during pregnancy (n = 12) or after delivery (n = 4).
Maternal-fetal adverse events were common (fetal loss, 11%; pre-term birth, 0–26%; pre-eclampsia, 15%), but overall the maternal kidney function was well preserved. All patients diagnosed with MN prior to pregnancy were in remission at the time of conception. Worsening of proteinuria was seen during the 2nd trimester. Cyclosporin A plus steroids were used to induce remission in the 2nd trimester and were successful in 3 of 8 cases. Similar results were found when treatment begun in the 3rd trimester. Rituximab was not used in any patient. The live birth rate was 89% with an average gestation period of 37 weeks. The average birth weight of the infants was 2.9 kg. Only 2 infants had transient low-grade proteinuria at birth, which spontaneously abated. A number of the mothers were phospholipase A2 receptor (PLA2R) antibody positive (about 30%). Marked proteinuria, a decrease in serum albumin, positive PLA2R antibody, and no remission were risk factors for adverse fetal maternal outcomes.
This paper is a valuable addition to the literature on pregnancy in MN. It contains sufficient detail to help guide the management of such patients. Cyclosporin A seems to be a reasonable treatment approach in situations that call for active treatment, but overall efficacy and safety cannot be assessed in such a small, uncontrolled sample. PLA2R antibody positivity, especially with rising levels, seems to be a reason for the introduction of active therapy. Infants do not appear to be seriously affected by the trans-placental transfer of anti-PLA2R antibody. We still do not know if rituximab therapy of primary MN in pregnancy is safe and effective.
