Risk of Adverse Pregnancy Outcomes in Women with CKD

Abstract

CKD is increasingly prevalent in pregnancy. In the Torino-Cagliari Observational Study (TOCOS), we assessed whether the risk for adverse pregnancy outcomes is associated with CKD by comparing pregnancy outcomes of 504 pregnancies in women with CKD to outcomes of 836 low-risk pregnancies in women without CKD. The presence of hypertension, proteinuria (>1 g/d), systemic disease, and CKD stage (at referral) were assessed at baseline. The following outcomes were studied: cesarean section, preterm delivery, and early preterm delivery; small for gestational age (SGA); need for neonatal intensive care unit (NICU); new onset of hypertension; new onset/doubling of proteinuria; CKD stage shift; "general" combined outcome (preterm delivery, NICU, SGA); and "severe" combined outcome (early preterm delivery, NICU, SGA). The risk for adverse outcomes increased across stages (for stage 1 versus stages 4-5: "general" combined outcome, 34.1% versus 90.0%; "severe" combined outcome, 21.4% versus 80.0%; P<0.001). In women with stage 1 CKD, preterm delivery was associated with baseline hypertension (odds ratio [OR], 3.42; 95% confidence interval [95% CI], 1.87 to 6.21), systemic disease (OR, 3.13; 95% CI, 1.51 to 6.50), and proteinuria (OR, 3.69; 95% CI, 1.63 to 8.36). However, stage 1 CKD remained associated with adverse pregnancy outcomes (general combined outcome) in women without baseline hypertension, proteinuria, or systemic disease (OR, 1.88; 95% CI, 1.27 to 2.79). The risk of intrauterine death did not differ between patients and controls. Findings from this prospective study suggest a "baseline risk" for adverse pregnancy-related outcomes linked to CKD.

Keywords: CKD; clinical nephrology; hypertension; obstetric nephrology; proteinuria; risk factors.

Figure 1.

Flow chart of the cases reported in the two study settings.

Figure 2.

Flow chart of the controls. PE, preeclampsia; PIH, pregnancy induced hypertension.

Figure 3.

Forest plot and random-effects meta-analysis of the general combined outcome (preterm delivery, SGA, NICU) in different selections of CKD stage 1 versus low-risk pregnancies. Results for Turin are presented as follows: all cases (OR, 2.66; 95% CI, 1.85 to 3.83), no systemic disease (OR, 2.40; 95% CI, 1.65 to 3.50), no systemic disease and proteinuria <1 g/d (OR, 2.12; 95% CI, 1.43 to 3.13), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.84; 95% CI, 1.21 to 2.78), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 2.01; 95% CI, 1.25 to 3.23). Results for Cagliari are presented as follows: all cases (OR, 3.12; 95% CI, 1.13 to 5.01), no systemic disease (OR, 2.71; 95% CI, 1.59 to 4.61), no systemic disease and proteinuria <1 g/d (OR, 2.63; 95% CI, 1.53 to 4.53), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.89; 95% CI, 0.94 to 3.80), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 2.11; 95% CI, 0.99 to 4.53). Results for both Turin and Cagliari are presented as follows: all cases (OR, 2.67; 95% CI, 2.00 to 3.55), no systemic disease (OR, 2.33; 95% CI, 1.72 to 3.14), no systemic disease and proteinuria <1 g/d (OR, 2.13; 95% CI, 1.56 to 2.91), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.68; 95% CI, 1.19 to 2.38), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 1.88; 95% CI, 1.27 to 2.79). 95% CI, 95% confidence interval.

Figure 4.

Forest plot and random-effects meta-analysis of the “severe” combined outcome (early preterm delivery, SGA, NICU) in different selections of CKD stage 1 versus low-risk pregnancies. Results for Turin are presented as follows: all cases (OR, 2.06; 95% CI, 1.37 to 3.12), no systemic disease (OR, 1.79; 95% CI, 1.64 to 2.76), no systemic disease and proteinuria <1 g/d (OR, 1.65; 95% CI, 1.05 to 2.59), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.47; 95% CI, 0.91 to 2.36), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 1.53; 95% CI, 0.87 to 2.66). Results for Cagliari are presented as follows: all cases (OR, 1.89; 95% CI, 2.00 to 3.24), no systemic disease (OR, 2.10; 95% CI, 1.16 to 3.70), no systemic disease and proteinuria <1 g/d (OR, 1.93; 95% CI, 1.06 to 3.50), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.28; 95% CI, 0.57 to 2.88), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 1.17; (95% CI, 0.47 to 2.87). Results for both Turin and Cagliari are presented as follows: all cases (OR, 1.93; 95% CI, 1.39 to 2.66), no systemic disease (OR, 1.77; 95% CI, 1.26 to 2.50), no systemic disease and proteinuria <1 g/d (OR, 1.66; 95% CI, 1.16 to 2.36), no systemic disease and proteinuria <1 g/d and normotension (OR, 1.31; 95% CI, 0.88–1.96), and no systemic disease and proteinuria <1 g/d and normotension and referral within 20 gestational weeks (OR, 1.33; 95% CI, 0.84 to 2.13).