A Systematic Review and Meta-Analysis of Outcomes of Pregnancy in CKD and CKD Outcomes in Pregnancy

Abstract

Background and objectives: We undertook a systematic review and meta-analysis of published cohort studies and case-control studies to estimate (1) the risk of pregnancy complications among patients with CKD versus those without CKD and (2) the risk of CKD progression among pregnant patients versus nonpregnant controls with CKD.

Design, setting, participants, & measurements: We searched electronic databases for studies published between 1946 and 2014, and we reviewed articles using validity criteria. Random-effects analytical methods were used.

Results: Twenty-three studies (14 with data for adverse pregnancy outcomes and 9 for renal outcomes) with 506,340 pregnancies were included. Pregnancy with CKD had greater odds of preeclampsia (odds ratio [OR], 10.36; 95% confidence interval [95% CI], 6.28 to 17.09), premature delivery (OR, 5.72; 95% CI, 3.26 to 10.03), small for gestational age/low birth weight (OR, 4.85; 95% CI, 3.03 to 7.76), cesarean section (OR, 2.67; 95% CI, 2.01 to 3.54), and failure of pregnancy (OR, 1.80; 95% CI, 1.03 to 3.13). Subgroup analysis showed that odds of preeclampsia (P<0.01) and premature delivery (P<0.01) were higher in women with nondiabetic nephropathy compared with diabetic nephropathy, and the odds of preeclampsia (P=0.01) and premature delivery (P<0.01) were higher in women with macroproteinuria compared with microproteinuria. The median for follow-up time for renal events was 5 years (interquartile range, 5-14.7 years). There were no significant differences in the occurrence of renal events between CKD pregnant women and those without pregnancy (OR, 0.96; 95% CI, 0.69 to 1.35). Subgroup analysis showed that publication year, sample size, follow-up years, type of primary disease, CKD classification, level of serum creatinine at baseline, proteinuria, and level of systolic BP did not modify the renal outcomes.

Conclusions: The risks of adverse maternal and fetal outcomes in pregnancy are higher for women with CKD versus pregnant women without CKD. However, pregnancy was not a risk factor for progression of renal disease in women with CKD before pregnancy.

Keywords: cesarean section; chronic kidney disease; follow-up studies; gestational age; humans; infant; low birth weight; pre-eclampsia; pregnancy; premature birth; renal function.

Figure 1.

Flow chart showing the number of citations retrieved by individual searches and number of trials included in the systematic review.

Figure 2.

Overall odds ratios of the association of CKD and preeclampsia. 95% CI, 95% confidence interval.

Figure 3.

Overall odds ratios of the association of CKD and failure of pregnancy (including stillbirth, fetal death, and neonatal death). 95% CI, 95% confidence interval.

Figure 4.

Odds ratios of CKD on pregnancy complications according to subgroups of publication year, sample size, type of study population, and proteinuria. Microproteinuria indicates albuminuria 30–300 mg/24 h or total proteinuria 150–500 mg/24 h, whereas macroproteinuria indicates albuminuria ≥300 mg/24 h or total proteinuria ≥500 mg/24 h. 95% CI, 95% confidence interval; DN, diabetic nephropathy; SGA, small for gestational age.

Figure 5.

Overall odds ratios of the association of pregnancy and renal events (including doubling of serum creatinine levels, 50% decrement of eGFR/CCr, and ESRD). 95% CI, 95% confidence interval; CCr, creatinine clearance rate.

Figure 6.

Odds ratios of pregnancy on renal outcomes according to subgroups of sample size, publication year, follow-up year, type of study population, CKD classification, baseline serum creatinine, baseline systolic BP, and baseline proteinuria. 95% CI, 95% confidence interval; A, albuminuria (mg/24 h); DN, diabetic nephropathy; SBP, systolic BP; SCr, serum creatinine; T, total proteinuria (g/24 h).

Figure 7.

Outcome of eGFR/CCr in women with CKD after pregnancy compared with non-pregnancy. 95% CI, 95% confidence interval; CCr, creatinine clearance rate. IV, method of analysis was inverse variance.