#4875 MANAGEMENT OF TUBULOINTERSTITIAL DISEASE IN PREGNANCY: TEN-YEARS EXPERIENCE OF A NEPHRO-OBSTETRIC CLINIC

Abstract Background and Aims Tubular renal acidosis and salt losing nephropathies are rare conditions but their management during pregnancy that can be challenging due to the physiological adaptation of kidney function. Herein, the authors report the management and outcomes of 7 gestations in patients with Gitelman disease (GS) and renal tubular acidosis (RTA). Method Retrospective analysis of maternal, obstetric and perinatal outcomes of pregnant women with tubulointerstitial diseases surveilled at our Nephro-Obstetric clinic from 2011 to 2021. Results We evaluated 7 pregnancies in 5 women. Mean age was 29 years [21-36]. They were all caucasian. Genetic diagnosis was performed during pregnancy in only one patient. Tubular disorder was caused by Gitelman disease in 3 patients and by renal tubular acidosis in 2 patients (ATP6VA4 and REN genes mutations). There were 4/1 patients in CKD G1/G3a, respectively, and none developed renal function deterioration. Only one patient developed transient proteinuria during both gestations and all patients had a low blood pressure profile. Management during the first trimester was especially challenging in GS patients, due to nausea, vomiting and hyperemesis gravidarum, which required hospital admission for intravenous potassium chloride therapy in all GS patients during the first trimester. Potassium levels in GS patients were generally below normal levels throughout pregnancy (mean 3 meq/L; 2,2-3,4 meq/L), even with progressive increase in therapy. Pre-pregnancy potassium chloride replacement increased from 4–10 tablets of 600 mg/day to a maximum of 9–21 tablets/day. One patient was also treated with spironolactone. The need for oral magnesium slightly increased from 2–3 ampoules of 1500mg/day to 2–4 ampoules/day. GS patients frequently complained of astenia and cramps. Regarding RTA patients, there was also a need to increase sodium bicarbonate dosage from 3–4.5g/day to a maximum of 2–8g /day. Regarding obstetric and perinatal outcomes, none of the patients developed preclampsia, mean gestational age at delivery was 40 weeks (38-41), mean birth weight was 3233g (2775-3825) and mean Apgar score was 10/10/10 at 1st, 5th and 10th minutes respectively. Conclusion In GS patients, management in the first trimester of pregnancy can be challenging due to nausea and vomiting, generally requiring admission for therapy with iv potassium. In spite of increasing doses in oral supplementation, ionic and acid base homeostasis during pregnancy is difficult to achieve. In our small series, maternal, obstetric and perinatal outcomes do not seem to be affected by this unbalance.