Incidence, Treatment, and Implications of Kidney Stones During Pregnancy: A Matched Population-Based Cohort Study

Comparison of Radiation Exposure for Pregnant Patients Requiring Intervention for Suspected Obstructing Nephrolithiasis

OBJECTIVE

To identify the differences in radiation exposure per suspected stone episode between percutaneous nephrostomy tube (PCN), stent, and primary ureteroscopy (URS).The incidence of nephrolithiasis in pregnancy is low; however, repercussions for both mother and fetus can be significant. In cases of suspected obstructing nephrolithiasis, intervention may be required, including ureteral stent, PCN, or URS, with the potential for multiple subsequent procedures that often utilize fluoroscopy.

METHODS

Pregnant patients who required an intervention (stent, PCN, or URS) for suspected obstructing nephrolithiasis were retrospectively reviewed. The primary outcome was total fluoroscopy exposure per suspected stone episode. Secondary outcomes included fluoroscopic exposure per procedure and number of procedures required.

RESULTS

After excluding patients with renal anomalies and incomplete radiation data, 78 out of 100 patients were included in the analysis. Forty patients (51.3%) underwent initial stent placement, 22 (28.2%) underwent initial PCN placement, and 16 (20.5%) underwent primary URS. Total mean radiation exposure per stone episode was significantly higher in patients who underwent PCN, (286.9 mGy vs 3.7 mGy (stent) and 0.2 mGy (URS), P <.001). In addition, patients who underwent initial PCN placement had significantly more procedures (P <.001) and mean radiation exposure per procedure was higher (P <.001). More than 40% of PCNs experienced dysfunction, and mean duration between PCN exchanges was 16.5 days.

CONCLUSION

In pregnant patients with suspected obstructing nephrolithiasis requiring intervention, initial PCN placement was associated with a significantly higher number of procedures, radiation exposure per procedure, and total radiation exposure per suspected stone episode compared to stent and URS.

2022 Recommendations of the AFU Lithiasis Committee: Management of symptomatic urinary stones

The acute situation, caused by an obstructive stone, is defined by a renal colic that may be uncomplicated, complicated, or at risk in specific conditions. Its management may be medical or require interventional treatment by extracorporeal shockwave lithotripsy, endoscopic removal, or ureteroscopy. METHODOLOGY: These recommendations were developed using two methods, the Clinical Practice Recommendations (CPR) and the ADAPTE method, in function of whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and whether they could be adapted to the French context.

Management of urolithiasis in pregnancy

Urolithiasis is the most common cause of nonobstetric abdominal pain, resulting in 1.7 admissions per 1000 deliveries. Urolithiasis most commonly occurs in the second and third trimesters, with an incidence between 1:125 and 1:2000. Acute urinary system obstructions are challenging to manage in obstetric patients because they contribute to physiological and anatomical changes that result in pathological outcomes. The restricted use of computed tomography in diagnosing and managing urolithiasis is particularly challenging. In addition, a prompt diagnosis is required because the presence of renal calculi during pregnancy increases the risk of fulminating sepsis and preterm delivery. Affected pregnancies are conservatively managed; however, 1 in 4 requires surgical intervention. Indications for surgical interventions are complex and range from nephrostomy insertion to empirical stent placement or ureteroscopy. Therefore, a multidisciplinary approach is required to optimize patient care. The diagnosis and management of urolithiasis in pregnancy are complex. We reviewed the role, safety, advantages and disadvantages of diagnostic tests and treatment used to manage acute urinary obstructions in pregnancy.

Pregnancy Outcomes in a Cohort of Patients Who Underwent Double-J Ureteric Stenting-A Single Center Experience

Background and Objectives: Minimally invasive procedures, such as double-J ureteric stenting, could be a promising therapeutic alternative to conservative management of obstructive urinary tract pathology. We aimed to evaluate the safety and effectiveness of double-J ureteric stenting in pregnant women with ureterohydronephrosis or urolithiasis, along with their infectious complications, and to assess the pregnancy outcomes of this cohort of patients in comparison with a control group. Materials and Methods: This observational retrospective study included 52 pregnant patients who underwent double-J ureteric stenting for urologic disorders in the Urology Department of ‘C.I. Parhon’ University Hospital, and who were followed up at a tertiary maternity hospital- ‘Cuza-Voda’, Iasi, Romania. The control group (63 patients) was randomly selected from the patient’s cohort who gave birth in the same time frame at the maternity hospital, without urinary pathology. Clinical, sonographic, and laboratory variables were examined. Descriptive statistics, non-parametric tests, and a one-to-one propensity score-matched analysis were used to analyze our data. Results: The univariate analysis indicated a significant statistical difference between the control group and the interventional group regarding maternal age (p = 0.018), previous maternal history of renal colic (p = 0.005) or nephrolithiasis (p = 0.002). After applying the propensity score-matched analysis, cesarean delivery rates (p < 0.001), preterm labour (p = 0.039), premature rupture of membranes (p = 0.026), preterm birth rates (p = 0.002), and post-partum UTI rates (p = 0.012) were significantly different between the control group and the matched treatment group. Ureterohydronephrosis, whether simple (n = 37; 71.2%) or infected (n = 13; 25%), was the main indication for double-J ureteric stenting. Complications such as pain (n = 21; 40.3%), stent migration (n = 3; 5.76%) or encrustation (n = 2; 3.84%), as well as reflux pyelonephritis (n = 2; 3.84%) and gross hematuria (n = 1; 1.92%) were recorded during follow-up. Conclusions: Our results show that double-J stenting is a safe and effective treatment option for pregnant patients with obstructive urological disorders.

Stent encrustation or fragmentation? A case report of post stent removal encrustation in postpartum woman and literature review

BACKGROUND

Ureteral stents are commonly used in the field of urology to relieve ureteral obstruction. However, complications relating to ureteral stent use, such as encrustation continue to occur, especially with prolonged indwell time.

CASE PRESENTATION

Here we present a 37-year-old postpartum woman with a foreign body in her bladder after removing a ureteral stent 1 month before. She insisted that the foreign body was the fragment of stent and asked for medical malpractice indemnity payments while the surgeon of her insisted that the stent was intact during the procedure. Finally, the foreign body was confirmed as an encrustation by cystoscopy and the patient received 10,000 yuan ($ 1500) as indemnity payments after encrustation removal.

CONCLUSION

In the absence of guidelines, stent indwelling time vary with centers' habits, stent materials and patient's education. Early detection of stent encrustation and timely removal of the encrusted stent are still the best way to avoid stent retention. Violent stent removal is of danger and not recommended in any case.

Risk of Symptomatic Kidney Stones During and After Pregnancy

RATIONALE & OBJECTIVE

There are several well-known anatomical and physiological changes during pregnancy that could contribute to kidney stone formation, but evidence that they increase the risk of kidney stones during pregnancy is lacking. We determined whether there was an increased risk of a first-time symptomatic kidney stone during and after pregnancy.

STUDY DESIGN

A population-based matched case-control study.

SETTING & PARTICIPANTS

945 female first-time symptomatic kidney stone formers aged 15-45 years and 1,890 age-matched female controls in Olmsted County, MN, from 1984-2012. The index date was the date of onset of a symptomatic kidney stone for both the case and her matched controls.

EXPOSURE

The primary exposure was pregnancy with assessment for variation in risk across different time intervals before, during, and after pregnancy. Medical records were manually reviewed to determine the conception and delivery dates for pregnancies.

OUTCOME

Medical record-validated first-time symptomatic kidney stone.

ANALYTICAL APPROACH

Conditional and unconditional multivariable logistic regression analysis.

RESULTS

Compared with nonpregnant women, the odds of a symptomatic kidney stone forming in women was similar in the first trimester (OR, 0.92; P=0.8), began to increase during the second trimester (OR, 2.00; P=0.007), further increased during the third trimester (OR, 2.69; P=0.001), peaked at 0 to 3 months after delivery (OR, 3.53; P<0.001), and returned to baseline by 1year after delivery. These associations persisted after adjustment for age and race or for diabetes mellitus, hypertension, and obesity. These results did not significantly differ by age, race, time period, or number of prior pregnancies. Having a prior pregnancy (delivery date>1year ago) was also associated with a first-time symptomatic kidney stone (OR, 1.27; P=0.01).

LIMITATIONS

Observational study design in a predominantly White population. The exact timing of stone formation cannot be determined.

CONCLUSIONS

Pregnancy increases the risk of a first-time symptomatic kidney stone. This risk peaks close to delivery and then improves by 1 year after delivery, though a modest risk of a kidney stone still exists beyond 1 year after delivery.

Risk of Postpartum Urinary Stone Disease in Women with History of Urinary Stone Disease During Pregnancy

OBJECTIVE

To determine the risk of postpartum urinary stone disease in women with a history of stone disease during pregnancy.

METHODS

Using the Optum® de-identified Clinformatics® Datamart we identified pregnant women with urinary stone disease in the United States between January 2003 to December 2017 by standardized ICD-9, ICD-10, and CPT code criteria. We limited the cohort to include women without evidence of urinary stone disease prior to pregnancy. We abstracted patient demographic characteristics, clinical risk factors for stone disease, and data for urinary stone disease encounters and related procedures after pregnancy. Encounters occurring within 1 year of pregnancy were excluded. Cox proportional hazard models were used to analyze for significance.

RESULTS

We identified a total of 1,395,783 pregnant women with a median postpartum follow-up of 4.0 years, including 5,971 (0.4%) women diagnosed with a urinary stone during pregnancy. Of these, 736 (12.3%) had an additional urinary stone diagnosis claim after pregnancy, compared with 13,275 (0.95%) women without a history of stone disease during pregnancy (p < 0.0001). In multivariable proportional hazards models urinary stone disease during pregnancy (HR 12.8, 95% CI [11.8 - 13.8]) was independently associated with a higher hazard of urinary stone disease after pregnancy.

CONCLUSION

Women urinary stone disease during pregnancy were more likely to present with recurrent urinary stone disease after pregnancy. Given the 1 in 8 chance of needing further care, women with history of stone disease during pregnancy may benefit from risk counseling, surveillance, or secondary prevention efforts in the postpartum period.

Maternal and neonatal outcomes of pregnancy complicated by urolithiasis: a systematic review and meta-analysis

BACKGROUND

The effect of urolithiasis on pregnancy-related outcomes remains unknown. The aim of this study was to determine the risk of adverse maternal and neonatal outcomes.

METHODS

We searched PubMed, Embase, and the Cochrane Library through December 2020 for studies reporting on adverse maternal and neonatal outcomes in patients with urolithiasis. Risk ratios (ORs) with 95% confidence intervals (CIs) were calculated for these outcomes in pregnant mothers with urolithiasis and compared to healthy controls.

RESULTS

Eight studies comprising 26,577 mothers with urolithiasis were included in our analysis. Preterm birth (OR = 1.63; 95% CI 1.37-1.95, p < 0.001) or very preterm birth risk (OR = 1.49, 95% CI 1.06-2.11, p = 0.02) was more common in patients with urolithiasis compared to healthy controls. Mothers with urolithiasis had an increased incidence of preeclampsia (OR = 1.75, 95% CI 1.33-2.3, p < 0.001), hypertension (OR = 2.97, 95% CI 1.31-6.71, p = 0.009), caesarean section (OR 1.31, 95% CI 1.11-1.55, p = 0.001), and gestational diabetes mellitus (OR 1.84, 95% CI 1.37-2.46, p < 0.001).

CONCLUSION

Patients with urolithiasis may be at increased risk of developing adverse maternal or neonatal outcomes.

Maternal and fetal outcomes of urolithiasis: A retrospective cohort study

OBJECTIVES

Although urolithiasis is relatively common in the general population, there is limited information on this condition available in the pregnant population. The objectives of this study are to identify the incidence of urolithiasis in pregnancy, as well as to compare maternal and fetal outcomes associated with urolithiasis in pregnancy.

METHODS

Using the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample database from the United States, a population-based retrospective cohort study consisting of pregnant women who delivered between 1999 and 2015 was conducted. ICD-9-CM code 592.X was used to identify pregnant women with urolithiasis within the cohort, with pregnant women without urolithiasis forming the comparison group. Unconditional logistic regression models were used to estimate the associations between urolithiasis in pregnancy and maternal and neonatal outcomes, while adjusting for baseline maternal characteristics.

RESULTS

A cohort of 13,792,544 pregnant women was identified, of which 11,528 had a urolithiasis-related admission during pregnancy, for an overall incidence of 8.3 per 10,000 pregnancies. Women with urolithiasis had a greater risk of developing preeclampsia/eclampsia, OR 1.35(95% CI 1.24-1.47), gestational diabetes, 1.29(1.20-1.30), abruptio placenta, 1.41(1.22-1.64), placenta previa, 1.55(1.27-1.90), pyelonephritis, 88.87(81.69-96.69), venous thromboembolism, 1.65(1.23-2.22), and more likely to deliver by cesarean, 1.20(1.15-1.25). As well, maternal death was more common among these women, 2.85(1.07-7.60). Congenital anomalies, 2.84(2.43-3.31) and prematurity, 1.92(1.82-2.03) were more commonly found among babies born to women with urolithiasis.

CONCLUSION

Although the mechanism is unclear, women with urolithiasis in pregnancy have an increased risk of adverse pregnancy and newborn outcomes.

Incidence of kidney stones in pregnancy and associations with adverse obstetrical outcomes: a systematic review and meta-analysis of 4.7 million pregnancies

BACKGROUND

Renal stones are a common cause of non-obstetrical abdominal pain in pregnant women. Though the management of renal stones in pregnancy is challenging, it remains unclear how the incidence of kidney stones may affect the course of pregnancy and delivery.

OBJECTIVE

To determine the incidence of renal stones in pregnancy and its impact on adverse obstetrical outcomes.

DATA SOURCES

We conducted a systematic literature search of three databases: Ovid MEDLINE, Ovid EMBASE, and EBSCO CINAHL Plus. After the selection of articles, an additional hand-search of their citations was completed to maximize sensitivity. Databases were examined from the last four decades (19 March 1970) up to the search date (19 March 2020).

STUDY ELIGIBILITY CRITERIA

Articles were excluded if they were not relevant to kidney stones or did not report outcomes related to pregnancy. Case reports, animal studies, and cadaveric studies were excluded. Conference abstracts, gray literature, and unpublished data were not eligible.

STUDY APPRAISAL AND SYNTHESIS METHODS

All screening, extraction, and synthesis were completed in duplicate with two independent reviewers. All outcomes reported in the included studies were systematically evaluated to determine suitability for meta-analysis. Random-effects models and sensitivity analyses were used to account for interstudy variation. Renal stone incidence rates were pooled to generate summary proportions. Risk of bias assessment was completed using the Risk of Bias Assessment tool for Non-randomized Studies.

RESULTS

Twenty-one studies were included through systematic review and approximately 4.7 million pregnancies across nine studies were included for meta-analysis. There are three major findings of this review regarding renal stone incidence in pregnancy and maternal, child, and birth-related outcomes associated with renal stones. First, we found pooled incidence of renal stones was 0.49%, or one case for every 204 pregnancies. Second, renal stones during pregnancy were significantly associated with the development of preeclampsia and urinary tract infection, as well as increased likelihood of low birth weight, preterm labor, and C-section deliveries. However, renal stones were not significantly associated with premature rupture of membranes or infant mortality. Third, there were limited obstetrical complications reported with either medical or surgical therapies although comparative outcomes were not provided in the majority of studies, precluding formal meta-analysis.

CONCLUSIONS

Although renal stones in pregnancy are relatively rare, there may be an associated risk of serious adverse obstetrical outcomes. However, further research is required to understand whether these obstetrical outcomes are causal or due to other confounders. Interdisciplinary care and pregnancy-specific counseling should be advised for pregnant women with kidney stones.

Urological issues in pregnancy: A review for urologists

Urological issues in the pregnant patient present a unique clinical dilemma. These patients may be challenging to treat due to risks associated with medications and surgical procedures. This review aims to provide an update on the physiological changes and surgical risks in pregnancy. In addition, we review the approach for management of urolithiasis and urinary tract infections in pregnancy. Lastly, we highlight the importance of a multidisciplinary approach to placenta percreta, a condition not commonly addressed in urological education.

Nephrolithiasis in Pregnancy: Treating for Two

OBJECTIVES

To review the literature regarding the epidemiology of stone disease and develop a management algorithm based on current evidence and societal guidelines.

METHODS

A structured literature review was performed to determine highest quality of evidence guiding care for pregnant patients with symptomatic nephrolithiasis. PUBMED and EMBASE databases were searched using terms "pregnancy," "nephrolithiasis," or "pregnancy" and "renal colic" alone and in combination with "stone", "kidney stone," "ultrasound," "MRI," "CT," "percutaneous nephrostomy," "ureteral stent," or "ureteroscopy." All English-language abstracts were reviewed for relevance and full-length articles were reviewed for content. Articles published prior to 1990 were excluded, and priority for inclusion was given to multi-institutional studies and larger institutional studies, reflecting the highest level of current available evidence and most contemporaneous practice patterns.

RESULTS

Symptomatic nephrolithiasis affects less than 1% of pregnancies but poses unique diagnostic challenges due to the physiologic changes of pregnancy and risks of ionizing radiation exposure to the fetus. Ultrasound remains the imaging modality of choice. Most patients may be managed non-operatively, but drainage with percutaneous nephrostomy or ureteral stent may be performed if warranted. Growing evidence also supports the safety and efficacy of definitive stone treatment.

CONCLUSIONS

Though rare, symptomatic nephrolithiasis poses significant clinical challenges due to the need to minimize risk for both mother and fetus with diagnostic and therapeutic interventions. A multi-disciplinary approach is paramount, as is shared decision making with the patient at each step of care.