Nutritional Challenges in Pregnant Women with Renal Diseases: Relevance to Fetal Outcomes

Risk factors for preeclampsia in patients with chronic kidney disease primarily focused on stage 1 CKD. Are referred and registered patients alike?

Limited research exists on identifying risk factors for preeclampsia (PE) in the chronic kidney disease (CKD) population, especially across different patient sources. This study aimed to address this gap by analyzing clinical data from CKD pregnant women admitted to Peking University Third Hospital from January 2012 to December 2022. Logistic regression analysis identified independent risk factors for PE in the CKD population and assessed variations among patients from different sources. Additionally, a predictive model for PE was established using data from the registered group. The study included 524 CKD patients. Hypertension, proteinuria, fibrinogen >4 g/L, serum albumin ≤30 g/L, and uric acid >260 μmol/L were independent risk factors for PE in the overall CKD population. Subgroup analysis revealed that hypertension, serum albumin ≤30 g/L, and uric acid >260 μmol/L were independent risk factors in the referred group, while hypertension, uric acid >260 μmol/L, and fibrinogen >4 g/L were independent risk factors in the registered group. The prediction model based on registered group risk factors showed good predictive efficiency, with the area under the curve of 0.774 in the training set and 0.714 in the validation set. In conclusion, this study revealed that hypertension and elevated uric acid are independent risk factors for PE in CKD patients regardless of patient source, while serum albumin and fibrinogen levels are associated with PE risk in specific patient subgroups. Our predictive model enables clinicians to quickly identify the risk of PE in CKD patients, and early intervention treatment to improve pregnancy outcomes.

Plant-Based Diets Improve Maternal-Fetal Outcomes in CKD Pregnancies

Reducing protein intake in patients with chronic kidney disease (CKD) limits glomerular stress induced by hyperfiltration and can prevent the progression of kidney disease; data in pregnancy are limited. The aim of this study is to analyze the results obtained in CKD patients who followed a plant-based moderately protein-restricted diet during pregnancy in comparison with a propensity-score-matched cohort of CKD pregnancies on unrestricted diets. A total of 52 CKD pregnancies followed up with a protein-restricted plant-based diet (Torino, Italy) were matched with a propensity score based on kidney function and proteinuria with CKD pregnancies with unrestricted protein intake (Cagliari Italy). Outcomes included preterm (<37 weeks) and very preterm (<34 weeks) delivery and giving birth to a small-for-gestational-age baby. The median age in our cohort was 34 years, 63.46% of women were primiparous, and the median body mass index (BMI) was 23.15 kg/m² with 13.46% of obese subjects. No statistical differences were found between women on a plant-based diet and women who were not in terms of age, parity, BMI, obesity, CKD stage, timing of referral, or cause of CKD. No differences were found between the two groups regarding the week of delivery. However, the combined negative outcome (birth before 37 completed gestational weeks or birth-weight centile <10) occurred less frequently in women following the diet than in women in the control group (61.54% versus 80.77%; p = 0.03). The lower risk was confirmed in a multivariable analysis adjusted for renal function and proteinuria (OR: 0.260 [Q1:0.093-Q3:0.724]; p = 0.010), in which the increase in proteinuria from the first to the last check-up before delivery was lower in patients on plant-based diets (median from 0.80 to 1.87 g/24 h; p: ns) than in controls (0.63 to 2.39 g/24 h p <0.0001). Plant-based, moderately protein-restricted diets in pregnancy in patients with CKD are associated with a lower risk of preterm delivery and small-for-gestational-age babies; the effect may be mediated by better stabilization of proteinuria.

Pregnancy and delivery in women receiving maintenance hemodialysis in Japan: analysis of potential risk factors for neonatal and maternal complications

Introduction

Average dialysis vintage in Japan is among the longest in the world, providing a unique opportunity to characterize pregnancy under conditions of long dialysis vintage. In 2017, we carried out a nationwide survey following up on a similar survey in 1996, in which we investigated the prevalence and outcomes of pregnancy in women undergoing dialysis and assessed risk factors associated with neonatal and maternal complications.

Methods

The target population was women aged 15–44 years undergoing maintenance dialysis between 2012 and 2016. The survey was conducted in 2693 dialysis units.

Results

A response was obtained from 951 dialysis units, yielding a target population of 1992 women of childbearing age receiving hemodialysis or peritoneal dialysis. Pregnancy occurred only among women receiving hemodialysis, with 25 pregnancies (1.26% in 5 years) being reported for 20 women. Detailed information about 19 pregnancies (mean age 34.6 ± 5.7 years at conception, mean dialysis vintage 8.4 ± 7.3 years) indicated 4 spontaneous abortions, 1 elective abortion, no neonatal deaths, and 14 surviving infants, including 5 full-term (≥ 37 weeks at birth), 2 late preterm (34–36), and 3 extremely preterm (< 28) cases. Neonatal complications occurred in the offspring of 3 mothers who had end-stage renal disease (ESRD) caused by primary glomerulonephritis and serum albumin levels (sAlb) ≤ 3.2 mg/dL in the first trimester. These mothers had started dialysis at 12, 17, and 30 years of age. ESRD caused by diabetic nephropathy or primary glomerulonephritis, age at conception ≥ 38 years, and sAlb ≤ 3.2 mg/dL were associated with maternal complications, although not significantly.

Conclusions

In this study, the pregnancy rate of Japanese women with ESRD was 0.25% per year. The study generates the hypothesis that ESRD caused by diabetic nephropathy and age at conception ≥ 38 years are potential risk factors for maternal complications but not for neonatal complications in dialysis patients, and that hypoalbuminemia is a potential risk factor for both kinds of complications.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01146-3.