Diagnostic yield and safety of percutaneous native kidney biopsy in pregnancy: 20-years of single-center experience.

BACKGROUND: Percutaneous kidney biopsy is a fundamental procedure in nephrology. Although pregnancy is not a contraindication, a careful risk-benefit assessment is mandatory in pregnancy. We aimed to evaluate safety and diagnostic accuracy of percutaneous kidney biopsy in pregnancy in a single-center retrospective study.

METHODS: Percutaneous kidney biopsy was performed in 19 pregnant patients. Demographics, estimated glomerular filtration rates, serum albumin levels, and proteinuria levels at the time of biopsy were evaluated. Biopsy-related complications, diagnoses, and treatments during the follow-up were analyzed. In addition, delivery success, preeclampsia, early delivery, low birth weight rates, and long-term outcomes of the patients were retrieved and analyzed.

RESULTS: Mean patient age was 27 (range 16-41) years. Median gestational week at kidney biopsy was 20th. All but one biopsies were diagnostic. Median gestational week of delivery was 35 (range 23-39) gestational weeks. Preterm delivery (< 37 gestational weeks) and low birth weight (< 2500 mg) occurred in 73.7% and 52.6% of cases, respectively. Median weight at birth was 2500 mg. The incidence of preeclampsia was 57.9%. Overall 89.5% of the children survived. Median post-biopsy follow-up was 64 months. Maternal mortality was not observed during the follow-up period. End stage kidney disease developed in one patient. The results of percutaneous kidney biopsy led to therapeutic decisions in 73.7% of cases.

CONCLUSIONS: Although percutaneous kidney biopsy is not frequently performed during pregnancy, it is relatively safe and usually diagnostic, and may guide further follow-up.