#84 Early to mid pregnancy renal parameters and adverse pregnancy outcomes in women with early stage chronic kidney disease

Abstract Background and Aims Early-stage chronic kidney disease (CKD) contributes to increased risk of adverse maternal and fetal outcomes in pregnancy. The impact of preconception factors is well understood, however few studies investigate links between renal parameters during pregnancy and adverse outcomes. We aimed to investigate whether renal ‘red flags’ in early to mid-pregnancy predict pregnancy complications in women with early-stage CKD. Method Retrospective data collection was undertaken from a single tertiary centre in Adelaide, Australia. All women with CKD stages 1–3 who had a pregnancy >20 weeks gestation between January 2018 and April 2023 were included. Maternal medical, infant and delivery data were collected from medical records. ‘Red flag’ markers were evaluated when available including: failure of serum creatinine to fall by 10% between pre-pregnancy and second trimester; protein:creatinine ratio (PCR) >30 mg/mmol in second trimester and lack of physiological drop in blood pressure between pre-pregnancy and second trimester. The primary outcome was a composite adverse pregnancy outcome of gestational age <37 weeks, birth weight <2500 grams and pre-eclampsia. Fisher's exact test was used to assess the relationship between red flag markers and the composite outcome. Results Results from 38 mothers and 47 pregnancies were analysed. There were three twin pregnancies and therefore 50 infants. Median maternal age at delivery was 32.5 years (IQR: 30.4–35.3). Stage 1 CKD was most common (n = 34, 72%), followed by stage 2 (n = 8, 17%) and stage 3 (n = 5, 11%). Glomerulonephritis was the most frequent cause of CKD (n = 23, 61%). 16% (n = 6) of mothers had chronic hypertension. Of the pregnancies 38% (n = 18) were complicated by hypertension and 19% (n = 9) by pre-eclampsia. The median birth weight of infants was 2895 grams (IQR: 2460–3170), with 6 (12%) <10th centile for gestational age. The median gestational age was 37.3 weeks (IQR 35.8–38). Red flags occurred in a high proportion of women: serum creatinine did not fall in 27/41 (61%), PCR was elevated in 24/35 (69%), and blood pressure did not fall in 24/33 (73%). The composite outcome occurred in 22/45 (49%). The rate of the composite outcome was not increased in women experiencing adverse renal parameters (creatinine 58%, P = 0.176; blood pressure 52%, P = 1.00; proteinuria 65%, P = 0.066). Conclusion Though this cohort of predominately early-stage CKD patients had a high rate of the composite adverse outcome, traditional red flags in mid-pregnancy were not consistently predictive of this. This highlights the need for alternative markers to assess risk throughout pregnancy.