Renal disease and chronic kidney disease in pregnancy

She is 32, a renal transplant for IgA nephropathy, on tacrolimus and azathioprine, baseline creatinine 95 micromol/L, twelve weeks pregnant. You are looking at the booking bloods and you can already see the questions an examiner will ask: is this safe, will the graft last, what does aspirin 150 mg actually do here, when do you deliver, and what do you tell her about her next pregnancy? CKD in pregnancy is no longer a "do-not-get-pregnant" disease — it is a planning problem, and the planning starts pre-conception.^[1][8]

Overview and definition

CKD complicates up to 3% of pregnancies, and its share is rising as women with transplants, diabetes and lupus reach reproductive age. The framing matters: in pregnancy, the kidney is haemodynamically transformed, the thresholds shift, and the disease that was invisible outside pregnancy becomes visible inside it.^[1][8]

• KDIGO definition (adapted for pregnancy): structural kidney abnormality, eGFR under 60 mL/min/1.73 m², or markers of kidney damage (proteinuria, haematuria, imaging change) persisting for at least 3 months. Pregnancy shortens the observation window pragmatically: any persistent abnormality at booking is treated as CKD until proven otherwise.^[1][18]
• What is abnormal in pregnancy: the kidney's job in pregnancy is to lower creatinine, not raise it. A booking serum creatinine above 75 micromol/L (0.85 mg/dL) is abnormal in pregnancy and demands an explanation.^[1][3]
• Proteinuria thresholds: PCR above 30 mg/mmol, ACR above 3 mg/mmol, or a 24-hour collection over 300 mg. Use PCR or ACR in clinic; reserve the 24-hour collection for the cases where the spot test and the picture disagree.^[1]

The one-line framing the examiner wants: CKD is the disease where pregnancy raises the bar — what was normal outside pregnancy is renal failure inside it.^[1]

References18ShowHide

1. [1]Williams D, Davison J Chronic kidney disease in pregnancy BMJ, 2008.PMID 18219043
2. [2]Piccoli GB, Cabiddu G, Attini R, et al. Risk of Adverse Pregnancy Outcomes in Women with CKD J Am Soc Nephrol, 2015.PMID 25766536
3. [3]Wiles K, Webster P, Seed PT, et al. The impact of chronic kidney disease Stages 3-5 on pregnancy outcomes Nephrol Dial Transplant, 2021.PMID 33313680
4. [4]Tangren J, Bathini L, Jeyakumar N, et al. Pre-Pregnancy eGFR and the Risk of Adverse Maternal and Fetal Outcomes: A Population-Based Study J Am Soc Nephrol, 2023.PMID 36735377
5. [5]Jeyaraman D, Walters B, Bramham K, et al. Adverse pregnancy outcomes in pregnant women with chronic kidney disease: A systematic review and meta-analysis BJOG, 2024.PMID 38488268
6. [6]Bramham K, Seed PT, Lightstone L, et al. Diagnostic and predictive biomarkers for pre-eclampsia in patients with established hypertension and chronic kidney disease Kidney Int, 2016.PMID 26924064
7. [7]Wiles K, Bramham K, Seed PT, et al. Placental and endothelial biomarkers for the prediction of superimposed pre-eclampsia in chronic kidney disease Pregnancy Hypertens, 2021.PMID 33677420
8. [8]Cabiddu G, Castellino S, Gernone G, et al. A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy J Nephrol, 2016.PMID 26988973
9. [9]Piccoli GB, Minelli F, Versino E, et al. Pregnancy in dialysis patients in the new millennium: a systematic review and meta-regression analysis correlating dialysis schedules and pregnancy outcomes Nephrol Dial Transplant, 2016.PMID 26614270
10. [10]Hladunewich MA, Hou S, Odutayo A, et al. Intensive hemodialysis associates with improved pregnancy outcomes: a Canadian and United States cohort comparison J Am Soc Nephrol, 2014.PMID 24525032
11. [11]Piccoli GB, Cabiddu G, Attini R, et al. Pregnancy outcomes after kidney graft in Italy: are the changes over time the result of different therapies or of different policies? A nationwide survey (1978-2013) Nephrol Dial Transplant, 2016.PMID 27604074
12. [12]Webster P, Wardle A, Bramham K, et al. Tacrolimus is an effective treatment for lupus nephritis in pregnancy Lupus, 2014.PMID 24928830
13. [13]Hladunewich MA, Bramham K, Jim B, et al. Managing glomerular disease in pregnancy Nephrol Dial Transplant, 2017.PMID 28391337
14. [14]Ankawi G, Tangirala N, Jesudason S, Hladunewich MA Pregnancy in Patients Receiving Home Dialysis Clin J Am Soc Nephrol, 2024.PMID 38285469
15. [15]Cabiddu G, Mannucci C, Fois A, et al. Pre-eclampsia is a valuable opportunity to diagnose chronic kidney disease: a multicentre study Nephrol Dial Transplant, 2022.PMID 34338783
16. [16]Piccoli GB, Attini R, Cabiddu G, et al. Maternal-foetal outcomes in pregnant women with glomerulonephritides. Are all glomerulonephritides alike in pregnancy? J Autoimmun, 2017.PMID 28279626
17. [17]Svetitsky S, Lightstone L, Wiles K Pregnancy in women with nephrotic-range proteinuria: A retrospective cohort study Obstet Med, 2024.PMID 38784182
18. [18]Piccoli GB, Ahmed SB, Fakhouri F, et al. Women and kidney health: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference Kidney Int, 2025.PMID 40439632