Elizabeth Ralston, Yanzhong Wang, Chris Farmer, Steve Childs, Ranjit Akolekar, Kate Bramham

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Women with CKD stages 3-5 are at higher risk of adverse pregnancy outcomes, including preterm delivery and low birthweight and progression of kidney disease. However, data describing outcomes of women with less severe kidney disease are limited, and few compare with women normal renal function. Furthermore, most studies report cohorts recruited from specialist clinics and may not be representative. This study aimed to describe pregnancy outcomes in a UK population cohort according to pre-conception eGFR \lt;90 ml/min/1.73 m2 compared with women with eGFR ≥90 ml/min/1.73 m2.

Routinely collected pregnancy data from three NHS Trust hospitals in Kent (UK) between 2010 and 2020 were extracted with Research Ethics Committee approval (19/LO/1242 and 18/SC/0158). Local laboratory and clinical data were linked to identify women with eGFR measured within two years of conception. Women without preconception creatinine were excluded from analysis. Baseline characteristics were described and comparisons between eGFR and adverse pregnancy and renal outcomes were tested.

A total of 14,243 pregnancies with confirmed pre-pregnancy creatinine were included, of which 1,405/14,243 (9.9\ had CKD stages 1-4 (stage 1: 221/14,243 (1.6\, stage 2: 1,170/14,243 (8.2\, stage 3: 12/14,243 (0.1\, stage 4: 2/14,243 (0.01\ (Table 1). Women with pre-pregnancy eGFR 60-89 ml/min/1.73 m2 (stage 2) were significantly older at conception than women without CKD (eGFR ≥90 ml/min/1.73 m2) but there were no significant differences in live birth rates, small for gestational age, gestation at delivery, and preterm birth. In pregnancies with CKD (1,405, stages 1-4), pre-pregnancy eGFR was weakly correlated with birthweight (rs = 0.05, p = 0.05), and gestational age (rs = 0.06, p = 0.05).Table 1:Summary of pregnancy outcomes according to pre-conception eGFR.eGFR \gt;90eGFR \gt; 90 ml/min/1.73 m2 with proteinuriaeGFR 60-89 ml/min/1.73 m2eGFR ≤59 ml/min/1.73 m2)(N = 12852)(N = 221)(N = 1170)(N = 14)Age at conception (mean (SD))27.5 (5.5)27.7 (5.9)30.8 (5.4)28.4 (6.4)Live birth (\10,226 (99.5)208 (99.5)956 (99.7)11 (100.0)Gestation at delivery (days) (median [IQR])278 [271, 284]274 [265, 281]277 [271, 284]278 [270.5, 283]Birthweight (mean (SD))3385 (706)3355 (653)3368 (615)3073 (663)Preterm birth \lt;34 weeks (\241 (2.3)6 (2.9)19 (2.0)0 (0.0)Small for gestational age 3rd centile (\128 (1.4)2 (1.2)16 (1.8)0 (0.0).

To our knowledge, this is the largest population cohort to describe pregnancy outcomes between women with eGFR 60-89 ml/min/1.73 m2 compared with eGFR ≥90 ml/min/1.73 m2. Women with eGFR 60-89 ml/min/1.73 m2 did not have worse renal or pregnancy outcomes compared to eGFR ≥90 ml/min/1.73 m2. Limitations include lack of proteinuria data and details of structural CKD (Class 1 CKD), and only one eGFR measurement prior to pregnancy may have led to some women with temporary reduction in function being included in the cohort. Overall, the findings suggest that women with eGFR 60-89 ml/min/1.73 m2 should not be discouraged from pregnancy.

Original languageEnglish
Article numbergfad063c_4482
JournalNephrology Dialysis Transplantation
Issue numberSupplement_1
Publication statusPublished - 1 Jun 2023


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