Pregnancy in Patients with Chronic Renal Insufficiency at Hospital de Clínicas of Porto Alegre, Brazil

Consensus recommendations on fasting during Ramadan for patients with kidney disease: review of available evidence and a call for action (RaK Initiative)

Ramadan fasting (RF) involves abstaining from food and drink during daylight hours; it is obligatory for all healthy Muslims from the age of puberty. Although sick individuals are exempt from fasting, many will fast anyway. This article explores the impact of RF on individuals with kidney diseases through a comprehensive review of existing literature and consensus recommendations. This study was conducted by a multidisciplinary panel of experts.The recommendations aim to provide a structured approach to assess and manage fasting during Ramadan for patients with kidney diseases, empowering both healthcare providers and patients to make informed decisions while considering their unique circumstances.

Thoracic organ transplantation and pregnancy outcomes: systematic review and meta-analysis

PURPOSE

Pre-conceptual comorbidities, an inherent risk of graft loss, rejection during pregnancy, and the postpartum period in women with thoracic lung transplant may predispose them to increased risk of adverse feto-maternal outcomes. The study aimed to systematically analyze and assess the risk of adverse pregnancy outcomes in women with thoracic organ transplant.

METHODS

MEDLINE, EMBASE, and Cochrane library were searched for publication between January 1990 and June 2020. Risk of bias was assessed using Joanna Briggs critical appraisal tool for case series. The primary outcomes included maternal mortality and pregnancy loss. The secondary outcomes were maternal complications, neonatal complications, and adverse birth outcomes. The analysis was performed using the DerSimonian-Laird random effects model.

RESULTS

Eleven studies captured data from 275 parturient with thoracic organ transplant describing 400 pregnancies. The primary outcomes included maternal mortality {pooled incidence (95% confidence interval) 4.2 (2.5-7.1) at 1 year and 19.5 (15.3-24.5) during follow-up}. Pooled estimates yielded 10.1% (5.6-17.5) and 21.8% (10.9-38.8) risk of rejection and graft dysfunction during and after pregnancy, respectively. Although 67% (60.2-73.2) of pregnancies resulted in live birth, total pregnancy loss and neonatal death occurred in 33.5% (26.7-40.9) and 2.8% (1.4-5.6), respectively. Prematurity and low birth weight were reported in 45.1% (38.5-51.9) and 42.7% (32.8-53.2), respectively.

CONCLUSIONS

Despite pregnancies resulting in nearly 2/3rd of live births, high incidence of pregnancy loss, prematurity and low birth weight remain a cause of concern. Focused pre-conceptual counseling to avoid unplanned pregnancy, especially in women with transplant-related organ dysfunctions and complications, is vital to improve pregnancy outcomes.

PROSPERO NUMBER

CRD42020164020.

Chronic kidney disease and adverse pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVE

Limited evidence exists on the role that the cause of chronic kidney disease plays in determining pregnancy outcomes. The aim of this systematic review and meta-analysis was to examine the association between chronic kidney disease and adverse pregnancy outcomes by the cause and severity of chronic kidney disease where reported. The protocol was registered under the International Prospective Register of Systematic Reviews (CRD42020211925).

DATA SOURCES

PubMed, Embase, and Web of Science were searched until May 24, 2021, supplemented with reference list checking.

STUDY ELIGIBILITY CRITERIA

Studies that compared the pregnancy outcomes in women with or without chronic kidney disease were included. Two reviewers independently screened titles, abstracts, and full-text articles according to a priori defined inclusion criteria.

METHODS

Data extraction and quality appraisal were performed independently by 3 reviewers. The grading of recommendations, assessment, development, and evaluation approach was used to assess the overall certainty of the evidence. Random-effects meta-analyses were used to calculate the pooled estimates using the generic inverse variance method. The primary outcomes included preeclampsia, cesarean delivery, preterm birth (<37 weeks' gestation), and small for gestational age babies.

RESULTS

Of 4076 citations, 31 studies were included. Prepregnancy chronic kidney disease was significantly associated with a higher odds of preeclampsia (pooled crude odds ratio, 8.13; [95% confidence interval, 4.41-15], and adjusted odds ratio, 2.58; [1.33-5.01]), cesarean delivery (adjusted odds ratio, 1.65; [1.21-2.25]), preterm birth (adjusted odds ratio, 1.73; [1.31-2.27]), and small for gestational age babies (adjusted odds ratio, 1.93; [1.06-3.52]). The association with stillbirth was not statistically significant (adjusted odds ratio, 1.67; [0.96-2.92]). Subgroup analyses indicated that different causes of chronic kidney disease might confer different risks and that the severity of chronic kidney disease is associated with a risk of adverse pregnancy outcomes, as pregnancies with later stages of chronic kidney disease had higher odds of preeclampsia, preterm birth, and small for gestational age babies than those at earlier stages. The grading of recommendations, assessment, development, and evaluation certainty of the evidence overall was "very low".

CONCLUSION

This meta-analysis quantified the associations between prepregnancy chronic kidney disease and adverse pregnancy outcomes, both overall and according to the cause and severity of the disease. These findings might support the clinicians aiming to counsel women having chronic kidney disease by allowing them to tailor their advice according to cause and severity of the chronic kidney disease. We identified the gaps in the literature, and further studies examining the effect of specific kidney diseases and other clinical characteristics (eg, proteinuria, hypertension) on adverse pregnancy outcomes are warranted.

Kidney-Placenta Crosstalk in health and disease

Organ crosstalk allows the interaction between systems to adapt to a constant changing environment, maintaining homeostasis. The process of placentation and the new hormonal environment during pregnancy trigger physiological changes that modulate kidney function to control extracellular volume, acid-base balance, and filtration of metabolic waste products. The bidirectional communication means that acute or chronic dysfunction of one organ can compromise the other. Abnormal placentation in pregnancy-related hypertensive disorders such as pre-eclampsia and HELLP (haemolysis, elevated liver enzymes and low platelet count) syndrome leads to the release of antiangiogenic factors that may cause kidney injury (thrombotic microangiopathy, glomeruloendotheliosis, mesangiolysis and vasoconstriction of peritubular vessels). These hypertensive disorders are a key cause of kidney injury in gestation, which increases maternal morbi-mortality and adverse foetal outcomes. Conversely, prior kidney injury or causes of kidney injury (diabetes, lupus, glomerulonephritis or other form of chronic kidney disease) increase the risk of developing hypertensive pregnancy disorders, providing a baseline higher risk. Inherited kidney diseases are a special concern, given the potential for genetic predisposition to kidney disease in the foetus. Understanding the bidirectional potential for compromise from placenta to kidney and vice versa provides a better framework to limit damage to both organs and improve maternal and foetal outcomes.

The impact of chronic kidney disease Stages 3-5 on pregnancy outcomes

Background

Contemporaneous data are required for women with chronic kidney disease (CKD) Stages 3–5 to inform pre-pregnancy counselling and institute appropriate antenatal surveillance.

Methods

A retrospective cohort study in women with CKD Stages 3–5 after 20 weeks’ gestation was undertaken in six UK tertiary renal centres in the UK between 2003 and 2017. Factors predicting adverse outcomes and the impact of pregnancy in accelerating the need for renal replacement therapy (RRT) were assessed.

Results

There were 178 pregnancies in 159 women, including 43 women with renal transplants. The live birth rate was 98%, but 56% of babies were born preterm (before 37 weeks’ gestation). Chronic hypertension was the strongest predictor of delivery before 34 weeks’ gestation. Of 121 women with known pre-pregnancy hypertension status, the incidence of delivery before 34 weeks was 32% (31/96) in women with confirmed chronic hypertension compared with 0% (0/25) in normotensive women. The risk of delivery before 34 weeks doubled in women with chronic hypertension from 20% [95% confidence interval (CI) 9–36%] to 40% (95% CI 26–56%) if the gestational fall in serum creatinine was <10% of pre-pregnancy concentrations. Women with a urinary protein:creatinine ratio >100 mg/mmol prior to pregnancy or before 20 weeks’ gestation had an increased risk for birthweight below the 10th centile (odds ratio 2.57, 95% CI 1.20–5.53). There was a measurable drop in estimated glomerular filtration rate (eGFR) between pre-pregnancy and post-partum values (4.5 mL/min/1.73 m²), which was greater than the annual decline in eGFR prior to pregnancy (1.8 mL/min/1.73 m²/year). The effect of pregnancy was, therefore, equivalent to 1.7, 2.1 and 4.9 years of pre-pregnancy renal disease in CKD Stages 3a, 3b and 4–5, respectively. The pregnancy-associated decline in renal function was greater in women with chronic hypertension and in those with a gestational fall in serum creatinine of <10% of pre-pregnancy concentrations. At 1 year post-partum, 46% (58/126) of women had lost ≥25% of their pre-pregnancy eGFR or required RRT. Most women with renal transplants had CKD Stage 3 and more stable renal function prior to pregnancy. Renal transplantation was not independently associated with adverse obstetric or renal outcomes.

Conclusions

Contemporary pregnancies in women with CKD Stages 3–5 are complicated by preterm delivery, low birthweight and loss of maternal renal function. 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 Stages 3–5. Pregnancy in women with CKD Stages 3–5 advances the need for dialysis or transplantation by 2.5 years.

Effect of dialysis on fetal heart rate: is inpatient admission for fetal monitoring necessary?

OBJECTIVE

Pregnant patients receiving hemodialysis (HD) have long hospital stays for the purpose of electronic fetal monitoring (EFM) during HD, which allows for monitoring of fetal well-being. However, more frequent dialysis allows for smaller fluid shifts, preventing maternal hypotension. Our aim was to determine differences in rates of EFM abnormalities during HD versus non-stress testing (NST) off dialysis for gravid women with renal failure.

METHODS

Retrospective cohort study over a 13-year period (2000-2013) identified five patients with renal failure in pregnancy. EFM tracings were reviewed during HD (cases) and routine inpatient NST off HD (controls). Standardized nomenclature was used to identify EFM abnormalities. The rate of abnormalities per hour of EFM was calculated. Kruskal-Wallis test was used and statistical significance was set at p < 0.05.

RESULTS

There were no significant differences in late decelerations (p = 0.2) between cases and controls. Significantly fewer variable decelerations (p = 0.01) and contractions (p ≤0.001) were noted during dialysis compared to controls. Significantly more prolonged decelerations (p = 0.02) were noted during HD compared to controls.

CONCLUSION

There may be no fetal benefit of EFM during HD for gravid women with renal disease attributed to hypertensive and diabetic nephropathy. There may be cost savings by shifting HD to the outpatient setting.

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

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.

Fetal tubuloglomerular feedback in an ovine model of mild maternal renal disease

Fetuses of pregnant ewes, which were subtotally nephrectomized prior to mating, were studied to assess whether mild maternal renal impairment would affect fetal tubuloglomerular feedback (TGF) under control conditions and after the inhibition of macula densa-derived nitric oxide (NO). Based on previous observations we hypothesized that, the TGF curve of fetuses of subtotally nephrectomized (STNx) ewes would resemble that of a volume expanded fetus with a high production rate of NO and that inhibition of neuronal nitric oxide synthase (nNOS) would increase the sensitivity of the TGF system in these fetuses. Renal function studies were performed on anaesthetized fetal sheep (133–140 days gestation; term ∼150 days; Isoflurane 2–4% in oxygen). Fetuses were removed from the uterus and placed in a water bath (39.5°C) while maintaining umbilical blood flow. Glomerular filtration rate (GFR) and urine flow rate were markedly increased in fetuses of STNx ewes compared to fetuses of untreated ewes. Interestingly, and contrary to our hypothesis, the fetuses of STNx ewes exhibited no difference in TGF sensitivity in the presence or absence of 7-nitroindazole (7NI; nNOS inhibitor), compared to fetuses of untreated ewes, although sensitivity and reactivity increased in both groups after 7NI. There was however, a decrease in the stop flow pressure and net filtration pressure with an increase in the filtration coefficient (K_f). These factors suggest that maternal renal impairment drives the glomerular hypertrophy which has previously been found to be present in the neonatal period. Thus, we conclude that at ∼138 days gestation, the fetal kidney has matured functionally and fetuses of STNx ewes are able to maintain fluid and electrolyte homeostasis even in the presence of increased transplacental flux.

Pregnancy in CKD: whom should we follow and why?

BACKGROUND

Chronic kidney disease (CKD) has a high prevalence in pregnancy. In a period of cost constraints, there is the need for identification of the risk pattern and for follow-up.

METHODS

Patients were staged according to K-DOQI guidelines. The analysis was prospective, January 2000-June 2011. Two hundred and forty-nine pregnancies were observed in 225 CKD patients; 176 singleton deliveries were recorded. The largest group encompasses stage 1 CKD patients, with normal renal function, in which 127 singleton deliveries were recorded. No hard outcomes occurred (death; dialysis); therefore, surrogate outcomes were analysed [caesarean section, prematurity, need for neonatal intensive care unit (NICU)]. Stage 1 patients were compared with normal controls (267 low-risk pregnancies followed in the same setting) and with patients with CKD stages 2-4 (49 singleton deliveries); two referral patterns were also analysed (known diagnoses; new diagnoses).

RESULTS

The risk for adverse pregnancy rises significantly in stage 1 CKD, when compared with controls: odds ratios were caesarean section 2.73 (1.72-4.33); preterm delivery 8.50 (4.11-17.57); NICU 16.10 (4.42-58.66). The risks rise in later stages. There is a high prevalence of new CKD diagnosis (overall: 38.6%; stage 1: 43.3%); no significant outcome difference was found across the referral patterns. Hypertension and proteinuria are confirmed as independent risk factors.

CONCLUSIONS

CKD is a risk factor in pregnancy; all patients should be followed within dedicated programmes from stage 1. There is need for dedicated interventions and educational programmes for maximizing the diagnostic and therapeutic potentials in early CKD stages.

Pregnancy outcomes in women with chronic kidney disease: a systematic review

BACKGROUND AND OBJECTIVES

Pregnant women with chronic kidney disease (CKD) are at risk of adverse maternal and fetal outcomes. We conducted a systematic review of observational studies that described this risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched several databases from their date of inception through June 2010 for eligible articles published in any language. We included any study that reported maternal or fetal outcomes in at least five pregnant women in each group with or without CKD. We excluded pregnant women with a history of transplantation or maintenance dialysis.

RESULTS

We identified 13 studies. Adverse maternal events including gestational hypertension, pre-eclampsia, eclampsia, and maternal mortality were reported in 12 studies. There were 312 adverse maternal events among 2682 pregnancies in women with CKD (weighted average of 11.5%) compared with 500 events in 26,149 pregnancies in normal healthy women (weighted average of 2%). One or more adverse fetal outcomes such as premature births, intrauterine growth restriction, small for gestational age, neonatal mortality, stillbirths, and low birth weight were reported in nine of the included studies. Overall, the risk of developing an adverse fetal outcome was at least two times higher among women with CKD compared with those without.

CONCLUSIONS

This review summarizes current available evidence to guide physicians in their decision-making, advice, and care for pregnant women with CKD. Additional studies are needed to better characterize the risks.

Pregnancy and chronic kidney disease: a challenge in all CKD stages

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is a challenge for pregnancy. Its recent classification underlines the importance of its early phases. This study's aim was to evaluate outcomes of pregnancy according to CKD stage versus low-risk pregnancies followed in the same center.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The prospective analysis was conducted from January 2000 to May 2009 with the start of observation at referral and end of observation 1 month after delivery. Ninety-one singleton deliveries were studied; 267 "low-risk" singleton pregnancies served as controls. Because of the lack of hard end points (death, start of dialysis), surrogate end points were analyzed (cesarean section, prematurity, neonatal intensive care).

RESULTS

CKD outcome was worse than physiologic pregnancies: preterm delivery (44% versus 5%); cesarean section (44% versus 25%); and need for neonatal intensive care (26% versus 1%). The differences were highly significant in stage 1 CKD (61 cases) versus controls (CKD stage 1: cesarean sections = 57%, preterm delivery = 33%, intensive care = 18%). In CKD, proteinuria and hypertension were correlated with outcomes [proteinuria dichotomized at 1 g/24 h at referral: need for intensive care, relative risk (RR) = 4.16 (1.05 to 16.46); hypertension: preterm delivery, RR = 7.24 (2.30 to 22.79); cesarean section, RR = 5.70 (1.69 to 19.24)]. Statistical significance across stages was reached for preterm delivery [RR = 3.32 (1.09 to 10.13)].

CONCLUSIONS

CKD is a challenge for pregnancy from early stages. Strict follow-up is needed for CKD patients, even when there is normal renal function.

Chronic Renal Disease in Pregnancy

The purpose of this review was to examine the impact of varying degrees of renal insufficiency on pregnancy outcome in women with chronic renal disease. Our search of the literature did not reveal any randomized clinical trials or meta-analyses. The available information is derived from opinion, reviews, retrospective series, and limited observational series. It appears that chronic renal disease in pregnancy is uncommon, occurring in 0.03-0.12% of all pregnancies from two U.S. population-based and registry studies. Maternal complications associated with chronic renal disease include preeclampsia, worsening renal function, preterm delivery, anemia, chronic hypertension, and cesarean delivery. The live birth rate in women with chronic renal disease ranges between 64% and 98% depending on the severity of renal insufficiency and presence of hypertension. Significant proteinuria may be an indicator of underlying renal insufficiency. Management of pregnant women with underlying renal disease should ideally entail a multidisciplinary approach at a tertiary center and include a maternal-fetal medicine specialist and a nephrologist. Such women should receive counseling regarding the pregnancy outcomes in association with maternal chronic renal disease and the effect of pregnancy on renal function, especially within the ensuing 5 years postpartum. These women will require frequent visits and monitoring of renal function during pregnancy. Women whose renal disease is further complicated by hypertension should be counseled regarding the increased risk of adverse outcome and need for blood pressure control. Some antihypertensives, especially angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers, should be avoided during pregnancy, if possible, because of the potential for both teratogenic (hypocalvaria) and fetal effects (renal failure, oliguria, and demise).

Maternal renal insufficiency alters plasma composition and renal function in the fetal sheep

To determine the effects of chronic maternal renal insufficiency on fetal renal function, we studied nine fetuses whose mothers underwent subtotal nephrectomy at least 2 mo before mating (STNxF) and seven fetuses from intact ewes (IntF) (126-128 days of gestation, term 150 days). STNxF had lower hematocrit (P < 0.05), plasma chloride (P < 0.01), and creatinine levels (P < 0.01), and the length-to-width ratio of their kidneys was reduced (P < 0.05). They excreted twice as much urine (P < 0.05) and sodium (P < 0.01). Total (P = 0.01) and proximal fractional sodium reabsorptions (P < 0.05) were lower in STNxF; distal delivery of sodium (P < 0.05) and distal fractional sodium reabsorption (P < 0.05) were higher. They tended to have suppressed renin levels (P = 0.06). Infusions of amino acids (alanine, glycine, proline, and serine at 0.32 mmol/min for 1 h and 0.64 mmol/min for 2 h intravenously), known to stimulate renal blood flow and glomerular filtration rate in fetal sheep, did so in IntF (P < 0.01). Arterial pressure also increased (P < 0.01). These effects were not observed in STNxF. In summary, chronic maternal renal insufficiency was associated with profound alterations in fetal renal excretion of fluid and electrolytes and impaired renal hemodynamic and glomerular responses to amino acid infusion. Whether these marked changes in the renal function of fetuses carried by STNx ewes are associated with alterations in renal function in postnatal or adult life remains to be determined.

Microvascular complications and the diabetic pregnancy

Without strict glycemic control, diabetic pregnancies are frequently complicated by spontaneous abortion, stillbirth, or congenital malformation. Retrospective studies have been largely reassuring that pregnancy does not accelerate morbid outcomes in women with diabetic vascular disease. Improved outcomes of high-risk pregnancy in women with pregestational, type 1, or type 2 diabetes mellitus remain challenging, depending on a comprehensive and multidisciplinary team approach and extensive preconception counseling.