*3.1. Characteristics of the Study Group*

Among the 34 pregnant patients with CKD, 19 (55.8%) developed preeclampsia, 26 (76.5%) had CKD stages 3-4, and the mean time of occurrence was at 31.26 ± 2.68 weeks of gestation. The mean maternal age was 24 ± 3.96 years and 3 (8.8%) patients were over 30 years old. The frequency of nulliparity in our group was 85.3%. The mean value of creatinine at referral was 1.6 ± 0.6 mg/dL. The median 24-h proteinuria at referral was 0.87 g/day (IQR 0.42–1.50) and 47.1% of patients had proteinuria of ≥1 g/day. The most frequent primary disease for CKD was glomerulonephritis (76.5%). Eight patients (23.5%) had a body mass index (BMI) of <sup>≥</sup>25 kg/m2 and half of the patients (50%) had pre-existing hypertension. None of our patients had a history of preeclampsia and there were no patients with CKD stage G5 (Table 1). Sixteen out of 19 (84.2%) patients developed PE < 34 weeks of gestation (early-onset PE) and in 3/19 (15.8%), PE occurred ≥ 34 weeks of gestation (late-onset PE).


**Table 1.** Characteristics of the study group.

eGFR—estimated glomerular filtration rate; BMI—body mass index; CKD—chronic kidney disease; a—statistical significance.

## *3.2. Comparison between Women With and Without Preeclampsia*

The characteristics of the women with superimposed preeclampsia on CKD and the differences between the two groups are summarized in Table 1. Patients with preeclampsia were more likely to be young (23.15 ± 2.31 vs. 25.66 ± 5.13, *p* = 0.06), hypertensive (63.2% vs. 33.3%, *p* = 0.08), dyslipidemic (31.6% vs. 20%, *p* = 0.44), and with decreased renal function at referral (46.16 ± 22.65 vs. 62.79 ± 21.4, *p* = 0.005) compared to those without preeclampsia. Furthermore, the preeclampsia group had significantly higher proteinuria (1.30 (IQR 0.67–1.50) vs. 0.63 (IQR 0.30–0.85) g/day, *p* = 0.02) and

13 of the 19 patients with preeclampsia had proteinuria ≥1 g/day at referral (68.7% vs. 20%, *p* = 0.005). Regarding fetal outcomes, fetal death occurred only in one pregnancy, the event taking place in the preeclampsia group (5.1%) and low birth weight was significantly higher in pregnant women with preeclampsia (84.2% vs. 6.7%, *p* < 0.001).
