Membranous Nephropathy in Pregnancy

<b><i>Background:</i></b> Primary membranous nephropathy (pMN) is less common in women of child-bearing age. The kidney risk factors to adverse maternal-fetal outcomes and the effects of pregnancy on pMN process need to be investigated. <b><i>Methods:</i></b> We retrospectively screened all the patients with biopsy-proven pMN from 2008 to 2018. Any cases of pregnancy that occurred at the time of pMN diagnosis or during follow-up were included in the study. Clinical and pathological data were collected from all patients at the time of kidney biopsy and their gestational results were recorded. <b><i>Results:</i></b> Of the 27 pregnancies with gestational time of 35.9 ± 4.5 weeks, 10 adverse maternal-fetal events occurred, including fetal loss (11%), preterm delivery (26%), and severe preeclampsia (15%). The kidney parameters were relatively stable with all preserved kidney function. Time-averaged urinary protein (<i>p</i> &#x3c; 0.001) and serum albumin (<i>p</i> &#x3c; 0.001), maximum urinary protein (<i>p</i> = 0.001) and minimum serum albumin (<i>p</i> = 0.01) before week 20, anti-phospholipase A2 receptor (PLA2R) positivity (<i>p</i> = 0.03), and no remission during pregnancy (<i>p</i> = 0.004) were risk factors to adverse maternal-fetal outcomes. Time-averaged urinary protein and serum albumin correlated with the birth weight percentile of neonates. <b><i>Conclusions:</i></b> Pregnancy in pMN patients showed risks to adverse maternal-fetal events. Heavy proteinuria, especially before week 20 of gestation, severe hypoalbuminemia, positive anti-PLA2R, and no remission were risk factors to worse outcomes.