What is the maternal mortality rate for pregnant women with stage 3 chronic kidney disease (estimated glomerular filtration rate < 60 mL/min/1.73 m²)?

Maternal Mortality in Stage 3 Chronic Kidney Disease

Direct Answer: Maternal Mortality is Not Significantly Elevated in Stage 3 CKD

Maternal mortality remains very low in stage 3 CKD, with live birth rates of 98% reported in contemporary cohorts, though the risk of severe maternal morbidity and accelerated renal decline is substantially increased. 1

Evidence on Maternal Outcomes in Stage 3 CKD

Mortality Data

• The live birth rate in women with CKD stages 3-5 is 98%, indicating that maternal death is rare even in moderate to severe kidney disease 1
• Maternal mortality is not the primary concern in stage 3 CKD; rather, the focus should be on maternal morbidity including accelerated renal decline, preeclampsia, and hypertensive complications 2

Stage-Specific Risk Stratification

• In mild CKD (serum creatinine <1.3 mg/dL, roughly corresponding to stage 3a), most pregnancies result in live births and maternal kidney function is typically unaffected 2
• Women with eGFR 60-89 mL/min/1.73 m² (stage 3a) face a 6.75-fold increased risk of composite maternal complications including worsening renal function or preeclampsia compared to stage 1 CKD 3
• Stage 3b CKD (eGFR 30-59 mL/min/1.73 m²) carries substantially higher risks of accelerated irreversible decline in maternal kidney function, proteinuria, and hypertensive complications 2

Critical Maternal Morbidity Risks

Accelerated Renal Decline

• Pregnancy causes a measurable drop in eGFR of 4.5 mL/min/1.73 m² between pre-pregnancy and post-partum values, which exceeds the annual decline in eGFR prior to pregnancy (1.8 mL/min/1.73 m²/year) 1
• The effect of pregnancy is equivalent to 2.1 years of pre-pregnancy renal disease in stage 3b CKD 1
• At 1 year post-partum, 46% of women with CKD stages 3-5 had lost ≥25% of their pre-pregnancy eGFR or required renal replacement therapy 1
• Pregnancy in women with CKD stages 3-5 advances the need for dialysis or transplantation by 2.5 years 1

Hypertensive Complications

• Chronic hypertension is the strongest predictor of severe maternal complications in stage 3 CKD 1
• Among women with confirmed chronic hypertension, 32% delivered before 34 weeks' gestation compared to 0% in normotensive women 1
• Preeclampsia risk increases dramatically: women with CKD stages 3-5 have a 55-fold increased risk compared to women without CKD 4
• Women with eGFR 60-89 mL/min/1.73 m² have significantly increased risk for preeclampsia 3

Additional Maternal Risks

• Women with CKD stages 3-5 have a 20-fold increased risk of requiring neonatal intensive care unit admission 4
• Cesarean section rates are significantly elevated in women with eGFR 60-89 mL/min/1.73 m² 3
• Worsening of renal failure during and following pregnancy is observed among all stages of CKD, with greater decline in GFR and progression to ESRD occurring earlier in unplanned pregnancies 5

Key Prognostic Factors Beyond CKD Stage

Chronic Hypertension

• Chronic hypertension, pre- or early pregnancy proteinuria, and a gestational fall in serum creatinine of <10% of pre-pregnancy values are more important predictors of adverse obstetric and renal outcome than CKD stage alone 1
• The risk of delivery before 34 weeks doubles from 20% to 40% in women with chronic hypertension if the gestational fall in serum creatinine is <10% of pre-pregnancy concentrations 1

Proteinuria

• Women with a urinary protein:creatinine ratio >100 mg/mmol prior to pregnancy or before 20 weeks' gestation have a 2.57-fold increased risk for birthweight below the 10th centile 1
• Maternal proteinuria portends negative outcomes and is an important factor to consider when risk stratifying for fetal and maternal complications 2

Fetal Outcomes (Relevant to Overall Pregnancy Risk)

• 56% of babies are born preterm (before 37 weeks' gestation) in women with CKD stages 3-5 1
• Women with CKD stages 3-5 have a 20-fold increased risk of preterm birth 4
• Intrauterine growth restriction occurs in 38.5% of pregnancies with eGFR 60-89 mL/min/1.73 m² 3
• Intrauterine fetal death occurs in 15.8% of pregnancies with eGFR 60-89 mL/min/1.73 m² 3

Clinical Implications for Pre-Pregnancy Counseling

• Women with stage 3 CKD should receive comprehensive pre-pregnancy counseling focusing on the high risk of preterm delivery, low birthweight, accelerated loss of maternal renal function, and hypertensive complications 1
• Planned pregnancies with regular obstetrical and nephrological follow-up result in better maternal and fetal outcomes compared to unplanned pregnancies 5
• Early referral for specialist care may prove useful for maternal and fetal outcome 5