Association of Unilateral Renal Agenesis With Adverse Outcomes in Pregnancy: A Matched Cohort Study

Evaluation of maternal and fetal outcomes in pregnancies with maternal solitary kidney: A case-control study from a tertiary center

INTRODUCTION

There exists a prevailing concern regarding the heightened susceptibility of women with a solitary kidney to unfavorable consequences during pregnancy. Irrespective of the underlying etiology, individuals with a solitary kidney are advised to have regular annual screenings for blood pressure and urinalysis due to their increased susceptibility to developing proteinuria, hypertension, and renal failure.

OBJECTIVE

To investigate the risk of adverse pregnancy outcomes in women with a maternal solitary kidney by comparing maternal and fetal outcomes to those of healthy pregnant women.

METHODS

This retrospective, single-center study was conducted with 29 pregnant women with maternal solitary kidney and 60 healthy controls at a tertiary hospital. Obstetric data such as gestational hypertension, preeclampsia, preterm labor, birth week, mode of delivery, Apgar scores, and neonatal intensive care requirements, were compared between the groups. A binary logistic regression analysis was performed to determine the obstetric complications increased by the presence of maternal solitary kidney.

RESULTS

The number of spontaneous abortions, serum creatinine and blood urea nitrogen levels were significantly higher in the patients with solitary kidney (p < 0.05). The birth week was earlier among the patients with a solitary kidney compared to the controls (p = 0.013). The preterm and cesarean delivery rates were also higher in the case group (p = 0.002 and p = 0.035, respectively). The pregnant women with solitary kidney were found to have higher rates of gestational hypertension, preeclampsia, and maternal intensive care requirements (p = 0.008, p = 0.015, and p = 0.008, respectively). Logistic regression analysis revealed a seven-fold increase in the rate of preterm labor (1.45-37.64) and a three-fold increase in preeclampsia (1.27-22.08) among the pregnant women with a solitary kidney.

CONCLUSION

Patients with solitary kidney are at high risk of encountering pregnancy complications, such as gestational hypertension, preeclampsia, and preterm labor. These pregnant women should be followed up carefully, starting from the first prenatal visit.

Hyperaldosteronism secondary to renal agenesis: An unusual cause for hypertension in pregnancy

Literature with regards to pregnancy related outcomes in persons with the presence of a solitary kidney of any cause is scarce. Most of the available information has been extrapolated from persons who have been renal donors. Unilateral renal agenesis affects 1 in 1500 people and can present with resistant hypertension. When a woman with a solitary kidney presents in pregnancy, it may be both a challenging diagnostic and therapeutic problem. Eplerenone, a selective aldosterone blocker has been prescribed for resistant hypertension and in the presence of pregnancy, been useful in persons with primary hyperaldosteronism and resistant hypertension due to obstructive sleep apnoea. We describe the use of Eplerenone in a patient with resistant hypertension in pregnancy, due to secondary hyperaldosteronism precipitated by renal agenesis.

Protein Misfolding in Pregnancy: Current Insights, Potential Mechanisms, and Implications for the Pathogenesis of Preeclampsia

Protein misfolding disorders are a group of diseases characterized by supra-physiologic accumulation and aggregation of pathogenic proteoforms resulting from improper protein folding and/or insufficiency in clearance mechanisms. Although these processes have been historically linked to neurodegenerative disorders, such as Alzheimer's disease, evidence linking protein misfolding to other pathologies continues to emerge. Indeed, the deposition of toxic protein aggregates in the form of oligomers or large amyloid fibrils has been linked to type 2 diabetes, various types of cancer, and, in more recent years, to preeclampsia, a life-threatening pregnancy-specific disorder. While extensive physiological mechanisms are in place to maintain proteostasis, processes, such as aging, genetic factors, or environmental stress in the form of hypoxia, nutrient deprivation or xenobiotic exposures can induce failure in these systems. As such, pregnancy, a natural physical state that already places the maternal body under significant physiological stress, creates an environment with a lower threshold for aberrant aggregation. In this review, we set out to discuss current evidence of protein misfolding in pregnancy and potential mechanisms supporting a key role for this process in preeclampsia pathogenesis. Improving our understanding of this emerging pathophysiological process in preeclampsia can lead to vital discoveries that can be harnessed to create better diagnoses and treatment modalities for the disorder.

Gestational Outcomes of Pregnant Women with Unilateral Congenital Renal Agenesis

ObjectiveWe evaluated if there were more adverse gestational outcomes of pregnant women with unilateral congenital renal agenesis (UCRA). Study design: This single center retrospective case-control study compared maternal complications and neonatal outcomes from 25 women with UCRA to the outcomes of 125 women with two kidneys. Results: UCRA women had lower gestational weeks at birth and higher rates of preterm delivery (p = 0.004 and <0.001; respectively). Mothers had higher rates of preeclampsia and newborns with congenital anomalies and neonatal intensive care unit (NICU) admission (p = 0.009, 0.042, and 0.039; respectively). Unadjusted odds ratios were significantly higher for preterm delivery and for any APGAR score of <7 at the first 10 min and preeclampsia [OR (95% CI):13.5 (4.66-39.05), 31 (3.44-279.32) and 5.76 (1.33-24.84), respectively]. Conclusion: Maternal UCRA is a risk factor for less optimal obstetric and neonatal outcomes.

Nephron-deficient HSRA rats exhibit renal injury with age but have limited renal damage from streptozotocin-induced hyperglycemia

Hypertension and diabetes are the greatest factors influencing the progression of chronic kidney disease (CKD). Investigation into the role of nephron number in CKD alone or with hypertension has revealed a strong inverse relationship between the two; however, not much is known about the connection between nephron number and diabetic kidney disease. The heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and hypertension and diabetes on CKD. HSRA rats exhibit failure of one kidney to develop in 50-75% of offspring, whereas the remaining offspring are born with two kidneys. Rats born with one kidney (HSRA-S) develop significant renal injury with age compared with two-kidney littermates (HSRA-C). The induction of hypertension as a secondary stressor leads to significantly more renal injury in HSRA-S compared with HSRA-C rats and nephrectomized HSRA-C (HSRA-UNX) rats. The present study sought to address the hypothesis that nephron deficiency in the HSRA rat would hasten renal injury in the presence of a secondary stressor of hyperglycemia. HSRA animals did not exhibit diabetes-related traits at any age; thus, streptozotocin (STZ) was used to induce hyperglycemia in HSRA-S, HSRA-C, and HSRA-UNX rats. STZ- and vehicle-treated animals were followed for 15 wk. STZ-treated animals developed robust hyperglycemia, but in contrast to the response to hypertension, neither HSRA-S nor HSRA-UNX animals developed proteinuria compared with vehicle treatment. In total, our data indicate that hyperglycemia from STZ alone does not have a significant impact on the onset or progression of injury in young one-kidney HSRA animals.NEW & NOTEWORTHY The HSRA rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and confounding cardiovascular complications that impact kidney health. Although hypertension was previously shown to exacerbate renal injury in young HSRA animals, diabetic hyperglycemia did not lead to worse renal injury, suggesting that nephron number has limited impact on kidney injury, at least in this model.

Clinical Management of Children with a Congenital Solitary Functioning Kidney: Overview and Recommendations

CONTEXT

A congenital solitary functioning kidney (cSFK) is a common developmental defect that predisposes to hypertension and chronic kidney disease (CKD) as a consequence of hyperfiltration. Every urologist takes care of patients with a cSFK, since some will need lifelong urological care or will come with clinical problems or questions to an adult urologist later in life.

OBJECTIVE

We aim to provide clear recommendations for the initial clinical management and follow-up of children with a cSFK.

EVIDENCE ACQUISITION

PubMed and EMBASE were searched to identify relevant publications, which were combined with guidelines on related topics and expert opinion.

EVIDENCE SYNTHESIS

Initially, cSFK diagnosis should be confirmed and risk factors for kidney injury should be identified using ultrasound. Although more research into early predictors of kidney injury is needed, additional congenital anomalies of the kidney or urinary tract and absence of compensatory kidney hypertrophy have repeatedly been associated with a worse prognosis. The role of voiding cystourethrography and antibiotic prophylaxis remains controversial, and is complicated by the exclusion of children with a cSFK from studies. A yearly follow-up for signs of kidney injury is recommended for children with a cSFK. As masked hypertension is prevalent, annual ambulatory blood pressure measurement should be considered. During puberty, an increasing incidence of kidney injury is seen, indicating that long-term follow-up is necessary. If signs of kidney injury are present, angiotensin converting enzyme inhibitors are the first-line drugs of choice.

CONCLUSIONS

This overview points to the urological and medical clinical aspects and long-term care guidance for children with a cSFK, who are at risk of hypertension and CKD. Monitoring for signs of kidney injury is therefore recommended throughout life. Large, prospective studies with long-term follow-up of clearly defined cohorts are still needed to facilitate more risk-based and individualized clinical management.

PATIENT SUMMARY

Many children are born with only one functioning kidney, which could lead to kidney injury later in life. Therefore, a kidney ultrasound is made soon after birth, and other investigations may be needed as well. Urologists taking care of patients with a solitary functioning kidney should realize the long-term clinical aspects, which might need medical management.

Preeclampsia and Kidney Disease: Deciphering Cause and Effect

PURPOSE OF REVIEW

Preeclampsia and chronic kidney disease have a complex, bidirectional relationship. Women with kidney disease, with even mild reductions in glomerular filtrate rate, have an increased risk of developing preeclampsia. Preeclampsia, in turn, has been implicated in the subsequent development of albuminuria, chronic kidney disease, and end-stage kidney disease. We will discuss observational evidence and mechanisms linking the two disease processes.

RECENT FINDINGS

Preeclampsia is characterized by an imbalance in angiogenic factors that causes systemic endothelial dysfunction. Chronic kidney disease may predispose to the development of preeclampsia due to comorbid conditions, such as hypertension, but is also associated with impaired glycocalyx integrity and alterations in the complement and renin-angiotensin-aldosterone systems. Preeclampsia may lead to kidney disease by causing acute kidney injury, endothelial damage, and podocyte loss. Preeclampsia may be an important sex-specific risk factor for chronic kidney disease. Understanding how chronic kidney disease increases the risk of preeclampsia from a mechanistic standpoint may open the door to future biomarkers and therapeutics for all women.

Acute IgA-Dominant Glomerulonephritis Associated with Syphilis Infection in a Pregnant Teenager: A New Disease Association

Chronic kidney disease (CKD) is increasingly recognized as a risk factor in pregnancy; the differential diagnosis between CKD and preeclampsia (PE) may be of pivotal importance for pregnancy management and for early treatment of CKD. Acknowledging this connection may be useful also in a wider context, such as in the case reported in this paper, which for the first time describes an association between syphilis infection and IgA-dominant glomerulonephritis. A 16-year-old woman, referred to a general hospital due to a seizure, was found to be unknowingly pregnant. Based on hypertension and nephrotic proteinuria, she was initially diagnosed with PE. Immunological tests, as well as hepatitis and HIV tests showed negative results. However, secondary syphilis was diagnosed. In discordance with the PE diagnosis, urinalysis showed glomerular microhematuria with cellular casts. Proteinuria and hypertension did not remit after delivery, which was made via caesarean section, due to uncontrolled hypertension, at an estimated gestational age of 29 weeks. A male baby, weighing 1.1 kg (6.5 centile) was born. The baby was hospitalized in the neonatal intensive care unit, where he developed subependymal hemorrhage and thrombocytopenia, and neonatal syphilis was diagnosed. The mother underwent a kidney biopsy one week after delivery, leading to the diagnosis of IgA-dominant postinfectious glomerulonephritis. Mother and child were treated with support and antibiotic therapy, and were discharged in good clinical conditions four weeks later. Four months after delivery, the mother was normotensive without therapy, with normal kidney function and without hematuria or proteinuria. In conclusion, this case suggests that IgA-dominant postinfectious glomerulonephritis should be added to the spectrum of syphilis-associated glomerulonephritides, and underlines the need for a careful differential diagnosis with CKD in all cases of presumed PE. While diagnosis relies on kidney biopsy, urinary sediment, a simple and inexpensive test, can be the first step in distinguishing PE from other nephropathies.

Risk of adverse maternal and fetal outcomes during pregnancy in living kidney donors: A matched cohort study

BACKGROUND

We examined the risk of adverse pregnancy outcomes in primiparous kidney donors compared to matched controls.

METHODS

Fifty-nine women with a history of kidney donation prior to their first pregnancy with normal renal function and no history of kidney disease, diabetes or chronic hypertension were matched 1:4 by age (within 2 years) and race to women with two kidneys using data from an integrated healthcare delivery system. Adverse pregnancy outcomes were defined as preterm delivery (delivery <37 weeks), delivery via cesarean section, gestational hypertension, preeclampsia/eclampsia, gestational diabetes, length of stay in the hospital >3 days, infant death/transfer to acute facility and low birthweight (<2500 g).

RESULTS

Living kidney donors did not have a higher risk of adverse outcomes compared to matched controls. There was a trend toward an increased risk of preeclampsia/eclampsia in kidney donors but it did not reach statistical significance (Odds ratio [OR]: 2.96, 95% CI: 0.98-8.94, P = 0.06). However, in kidney donors ≤30 years of age, there was a fourfold increased risk of preeclampsia/eclampsia (OR: 4.09, 95% CI: 1.07-15.59, P = 0.04).

CONCLUSION

Overall, the risk of pregnancy-associated complications following kidney donation is small but potential female kidney donors should be counseled on the possible increased risk of preeclampsia.

Pregnancy in women known to be living with a single kidney

There is a paucity of data on pregnancy outcome in women living with a single kidney from all causes. Current thinking is extrapolated from living kidney donors, a group biased by strict selection criteria. We present a cohort of 26 women with a solitary functioning kidney; 11 women had an acquired single kidney of whom only 1 was a living donor and 15 had a congenital single kidney. Median time living with a single kidney was 28 years. None booked with hypertension or proteinuria. Urinary tract infection complicated 50% of pregnancies. Worryingly, 35% developed pre-eclampsia, gestational proteinuria or gestational hypertension. We propose pre-conceptual counselling, education on how to protect their single kidney, pre eclampsia prophylaxis with low-dose aspirin and close monitoring for urinary tract infection, hypertension and proteinuria with lower thresholds for pharmaceutical management. We have devised a Patient Information leaflet - 'Living with a single kidney, pregnancy and beyond'.

Risk of Preeclampsia and Pregnancy Complications in Women With a History of Acute Kidney Injury

An episode of clinically recovered acute kidney injury (r-AKI) has been identified as a risk factor for future hypertension and cardiovascular disease. Our objective was to assess whether r-AKI was associated with future preeclampsia and other adverse pregnancy outcomes and to identify whether severity of AKI or time interval between AKI and pregnancy was associated with pregnancy complications. We conducted a retrospective cohort study of women who delivered infants between 1998 and 2016 at Massachusetts General Hospital. AKI was defined using the 2012 Kidney Disease Improving Global Outcomes laboratory criteria with subsequent clinical recovery (estimate glomerular filtration rate, >90 mL/min per 1.73 m² before conception). AKI was further classified by severity (Kidney Disease Improving Global Outcomes stages 1-3) and time interval between AKI episode and the start of pregnancy. Women with r-AKI had an increased rate of preeclampsia compared with women without previous r-AKI (22% versus 9%; P<0.001). Infants of women with r-AKI were born earlier (gestational age, 38.2±3.0 versus 39.0±2.2 weeks; P<0.001) and were more likely to be small for gestational age (9% versus 5%; P=0.002). Increasing severity of r-AKI was associated with increased risk of preeclampsia for stages 2 and 3 AKI (adjusted odds ratio, 3.5; 95% confidence interval, 2.1-5.7 and adjusted odds ratio, 6.5; 95% confidence interval, 3.5-12.0, respectively), but not for stage 1 (adjusted odds ratio, 1.7; 95% confidence interval, 0.9-3.2). A history of AKI before pregnancy, despite apparent full recovery, was associated with increased risk of pregnancy complications. Severity and timing of the AKI episode modified the risk.

Metabolic and Hypertensive Complications of Pregnancy in Women with Nephrolithiasis

BACKGROUND AND OBJECTIVES

Kidney stones are associated with future development of hypertension, diabetes, and the metabolic syndrome. Our objective was to assess whether stone formation before pregnancy was associated with metabolic and hypertensive complications in pregnancy. We hypothesized that stone formation is a marker of metabolic disease and would be associated with higher risk for maternal complications in pregnancy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study of women who delivered infants at the Massachusetts General Hospital from 2006 to 2015. Women with abdominal imaging (computed tomography or ultrasound) before pregnancy were included in the analysis. Pregnancy outcomes in women with documented kidney stones on imaging (stone formers, n=166) were compared with those of women without stones on imaging (controls, n=1264). Women with preexisting CKD, hypertension, and diabetes were excluded.

RESULTS

Gestational diabetes and preeclampsia were more common in stone formers than nonstone formers (18% versus 6%, respectively; P<0.001 and 16% versus 8%, respectively; P=0.002). After multivariable adjustment, previous nephrolithiasis was associated with higher risks of gestational diabetes (adjusted odds ratio, 3.1; 95% confidence interval, 1.8 to 5.3) and preeclampsia (adjusted odds ratio, 2.2; 95% confidence interval, 1.3 to 3.6). Infants of stone formers were born earlier (38.7±2.0 versus 39.2±1.7 weeks, respectively; P=0.01); however, rates of small for gestational age offspring and neonatal intensive care admission were similar between groups (8% versus 7%, respectively; P=0.33 and 10% versus 6%, respectively; P=0.08). First trimester body mass index significantly influenced the association between stone disease and hypertensive complications of pregnancy: in a multivariable linear regression model, stone formation acted as an effect modifier of the relationship between maximum systolic BP in the third trimester and body mass index (P interaction <0.001).

CONCLUSIONS

In women without preexisting diabetes, hypertension, and CKD, a history of nephrolithiasis was associated with gestational diabetes and hypertensive disorders of pregnancy, especially in women with high first trimester body mass index.

Obstetric outcome in patients with a unicornuate uterus after laparoscopic resection of a rudimentary horn

AIM

Previous studies have shown adverse obstetric outcomes of the laparoscopic resection of a rudimentary horn. Our study aimed to investigate the obstetric outcome in our institution and to review previous studies.

METHODS

Using a retrospective analysis, data were reviewed from singleton pregnancies with maternal uterine anomalies at a medical center in Osaka, Japan, between January 2011 and March 2016. The uterine anomaly cases were divided into a 'postlaparoscopic resection of the rudimentary horn' group (study group) and an 'other uterine anomalies' (bicornuate uterus, uterine didelphys and unicornuate uterus) group (control group). Primary outcomes of interest were differences in obstetric outcomes, such as spontaneous preterm birth rate, small for gestational age (SGA) infant rate and hypertensive disorders of pregnancy (HDP) rate between the study and the control group, and the secondary outcome of interest was mode of delivery in the study group.

RESULTS

Data from 40 deliveries were included in the study (7 deliveries: study group, 33 deliveries: control group). No significant difference was observed between the two groups in terms of either mean gestational weeks at delivery (36.4 weeks vs 37.1 weeks; P = .38), cesarean delivery rate (57.1% vs 57.5%; P = 1.0), SGA infant rate (<10th percentile) (0% vs 24.2%; P = .31) and HDP rate (0.0% vs 3.0%; P = 1.0). Three of seven cases with postlaparoscopic resection of the rudimentary horn were able to deliver vaginally without complications.

CONCLUSION

Our study shows that the obstetric outcome observed in the study group was similar to that observed in the control group.