Isolated gestational proteinuria preceding the diagnosis of preeclampsia - an observational study

Proteinuria during pregnancy: definition, pathophysiology, methodology, and clinical significance

Qualitative and quantitative measurement of urine protein excretion is one of the most common tests performed during pregnancy. For more than 100 years, proteinuria was necessary for the diagnosis of preeclampsia, but recent guidelines recommend that proteinuria is sufficient but not necessary for the diagnosis. Still, in clinical practice, most patients with gestational hypertension will be diagnosed as having preeclampsia based on the presence of proteinuria. Although the reference standard for measuring urinary protein excretion is a 24-hour urine collection, spot urine protein-to-creatinine ratio is a reasonable "rule-out" test for proteinuria. Urine dipstick screening for proteinuria does not provide any clinical benefit and should not be used to diagnose proteinuria. The classic cutoff cited to define proteinuria during pregnancy is a value of >300 mg/24 hours or a urine protein-to-creatinine ratio of at least 0.3. Using this cutoff, the rate of isolated proteinuria in pregnancy may reach 8%, whereas preeclampsia occurs among 3% to 8% of pregnancies. Although this threshold is widely accepted, its origin is not based on evidence on adverse pregnancy outcomes but rather on expert opinion and results of small studies. After reviewing the available data, the most important factor that influences maternal and neonatal outcome is the severity of blood pressures and presence of end organ damage, rather than the excess protein excretion. Because the management of gestational hypertension and preeclampsia without severe features is almost identical in frequency of surveillance and timing of delivery, the separation into 2 disorders is unnecessary. If the management of women with gestational hypertension with a positive assessment of proteinuria will not change, we believe that urine assessment for proteinuria is unnecessary in women who develop new-onset blood pressure at or after 20 weeks' gestation. Furthermore, we do not recommend repeated measurement of proteinuria for women with preeclampsia, the amount of proteinuria does not seem to be related to poor maternal and neonatal outcomes, and monitoring proteinuria may lead to unindicated preterm deliveries and related neonatal complications. Our current diagnosis of preeclampsia in women with chronic kidney disease may be based on a change in protein excretion, a baseline protein excretion evaluation is critical in certain conditions such as chronic hypertension, diabetes, and autoimmune or other renal disorders. The current definition of superimposed preeclampsia possesses a diagnostic dilemma, and it is unclear whether a change in the baseline proteinuria reflects another systemic disease such as preeclampsia or whether women with chronic disease such as chronic hypertension or diabetes will experience a different "normal" pattern of protein excretion during pregnancy. Finally, limited data are available regarding angiogenic and other biomarkers in women with chronic kidney disease as a potential aid in distinguishing the worsening of baseline chronic kidney disease and chronic hypertension from superimposed preeclampsia.

Routinely collected antenatal data for longitudinal prediction of preeclampsia in nulliparous women: a population-based study

The objective was to evaluate the sequentially updated predictive capacity for preeclampsia during pregnancy, using multivariable longitudinal models including data from antenatal care. This population-based cohort study in the Stockholm-Gotland Counties, Sweden, included 58,899 pregnancies of nulliparous women 2008-2013. Prospectively collected data from each antenatal care visit was used, including maternal characteristics, reproductive and medical history, and repeated measurements of blood pressure, weight, symphysis-fundal height, proteinuria, hemoglobin and blood glucose levels. We used a shared-effects joint longitudinal model including all available information up until a given gestational length (week 24, 28, 32, 34 and 36), to update preeclampsia prediction sequentially. Outcome measures were prediction of preeclampsia, preeclampsia with delivery < 37, and preeclampsia with delivery ≥ 37 weeks' gestation. The area under the curve (AUC) increased with gestational length. AUC for preeclampsia with delivery < 37 weeks' gestation was 0.73 (95% CI 0.68-0.79) at week 24, and increased to 0.87 (95% CI 0.84-0.90) in week 34. For preeclampsia with delivery ≥ 37 weeks' gestation, the AUC in week 24 was 0.65 (95% CI 0.63-0.68), but increased to 0.79 (95% CI 0.78-0.80) in week 36. The addition of routinely collected clinical measurements throughout pregnancy improve preeclampsia prediction and may be useful to individualize antenatal care.

Progression from isolated gestational proteinuria to preeclampsia with severe features

INTRODUCTION

The association between the degree of isolated gestational proteinuria and preeclampsia with severe features and other placental-mediated complications is controversial. The aim of this study was to evaluate whether a higher isolated proteinuria level is associated with an increased frequency of preeclampsia with severe features.

MATERIAL AND METHODS

This retrospective cohort study included pregnant women who were past 24 weeks of gestation and were diagnosed as having new-onset proteinuria ≥300 mg in a 24-h urine collection. Exclusion criteria included diagnosis of preeclampsia within 72 h from admission, chronic renal disease or chronic hypertension. The study population was divided into tertiles by proteinuria level and the association with preeclampsia with severe features was assessed in both bivariable and multivariable analysis. The main outcome measures was the development of preeclampsia with severe features.

RESULTS

Overall, 165 women were diagnosed with isolated gestational proteinuria, and 38 (23.0%) of them developed preeclampsia with severe features. Women in the increasing proteinuria tertile were more likely to develop preeclampsia with severe features (5.5%, 21.8%, 41.8%, respectively; p = 0.004). A multivariable logistic regression model controlling for background characteristics as well as gestational age at diagnosis, blood pressure, and kidney and liver function tests showed an increased risk of 14% to develop preeclampsia with severe features for every 500-mg rise in proteinuria level (adjusted odds ratio = 1.14, 95% confidence interval 1.03-1.27).

CONCLUSIONS

A higher isolated gestational proteinuria level was associated with an increased risk to develop preeclampsia with severe features among pregnant women past 24 weeks of gestation.

Earlier onset of proteinuria or hypertension is a predictor of progression from gestational hypertension or gestational proteinuria to preeclampsia

Although gestational hypertension (GH) is a well-known disorder, gestational proteinuria (GP) has been far less emphasized. According to international criteria, hypertensive disorders of pregnancy include GH but not GP. Previous studies have not revealed the predictors of progression from GP to preeclampsia or those of progression from GH to preeclampsia. We aimed to determine both sets of predictors. A retrospective cohort study was conducted with singleton pregnant women who delivered at 22 gestational weeks or later. Preeclampsia was divided into three types: new onset of hypertension/proteinuria at 20 gestational weeks or later and additional new onset of other symptoms at < 7 days or at ≥ 7 days later. Of 94 women with preeclampsia, 20 exhibited proteinuria before preeclampsia, 14 experienced hypertension before preeclampsia, and 60 exhibited simultaneous new onset of both hypertension and proteinuria before preeclampsia; the outcomes of all types were similar. Of 34 women with presumptive GP, 58.8% developed preeclampsia; this proportion was significantly higher than that of 89 women with presumptive GH who developed preeclampsia (15.7%). According to multivariate logistic regression models, earlier onset of hypertension/proteinuria (before or at 34.7/33.9 gestational weeks) was a predicator for progression from presumptive GH/GP to preeclampsia (odds ratios: 1.21/1.21, P value: 0.0044/0.0477, respectively).

Epidemiological trends of maternal hypertensive disorders of pregnancy at the global, regional, and national levels: a population-based study

BACKGROUND

Relevant studies focusing on epidemiological of profiles hypertensive disorders of pregnancy from global data that report the cause-specific prevalence and trends of hypertensive disorders of pregnancy at global, regional and national levels from 1990 to 2019 by age and sociodemographic index are still limited.

METHODS

For hypertensive disorders of pregnancy, point prevalence, annual incidence, and years lived with disability numbers and age standardized rates per 100,000 population were compared at regional and national levels by age and sociodemographic index using data from the global Burden of Disease 2019 Study, covering populations from 204 countries and territories. Estimates are reported with uncertainty intervals to exhibit the changing trends during a specific period.

RESULTS

The incidence of hypertensive disorders of pregnancy increased from 16.30 million to 18.08 million globally, with a total increase of 10.92 % from 1990 to 2019. The age-standardized incidence rate decreased, with an estimated annual percent change of -0.68 (95 % confidence interval [CI] -0.49 to -0.86). The number of deaths due to hypertensive disorders of pregnancy was approximately 27.83 thousand in 2019, representing a 30.05 % decrease from 1990. Based on the incidence and prevalence, the number of deaths and years lived with disability were highest in the group aged 25-29 years, followed by the groups aged 30-34 and 20-24 years, while the lowest estimated incidence rate was observed in the group aged 25-29 years and higher incidence rates were observed in the youngest and oldest groups. Positive associations between incidence rates and the sociodemographic index and human development index were found for all countries and regions in 2019. Age-standardized incidence rates were higher in countries/regions with lower sociodemographic indices and human development indices.

CONCLUSIONS

Our study provides a comprehensive overview of the global burden of hypertensive disorders of pregnancy. The death and incidence rates are decreasing in most countries and all regions except for those with low sociodemographic and human development indexes. This difference is mainly due to the increasing attention to prenatal examinations and health education. Further investigations should focus on forecasting the global disease burden of specific hypertensive disorders of pregnancy and modifiable risk factors.

Population-level data on antenatal screening for proteinuria; India, Mozambique, Nigeria, Pakistan

Objective

To estimate the prevalence and prognosis of proteinuria at enrolment in the 27 intervention clusters of the Community-Level Interventions for Pre-eclampsia cluster randomized trials.

Methods

We identified pregnant women eligible for inclusion in the trials in their communities in four countries (2013–2017). We included women who delivered by trial end and received an intervention antenatal care visit. The intervention was a community health worker providing supplementary hypertension-oriented care, including proteinuria assessment by visual assessment of urinary dipstick at the first visit and all subsequent visits when hypertension was detected. In a multilevel regression model, we compared baseline prevalence of proteinuria (≥ 1+ or ≥ 2+) across countries. We compared the incidence of subsequent complications by baseline proteinuria.

Findings

Baseline proteinuria was detected in less than 5% of eligible pregnancies in each country (India: 234/6120; Mozambique: 94/4234; Nigeria: 286/7004; Pakistan: 315/10 885), almost always with normotension (India: 225/234; Mozambique: 93/94; Nigeria: 241/286; Pakistan: 264/315). There was no consistent relationship between baseline proteinuria (either ≥ 1+ or ≥ 2+) and progression to hypertension, maternal mortality or morbidity, birth at < 37 weeks, caesarean section delivery or perinatal mortality or morbidity. If proteinuria testing were restricted to women with hypertension, we projected annual cost savings of 153 223 981 United States dollars (US$) in India, US$ 9 055 286 in Mozambique, US$ 53 181 933 in Nigeria and US$ 38 828 746 in Pakistan.

Conclusion

Our findings question the recommendations to routinely evaluate proteinuria at first assessment in pregnancy. Restricting proteinuria testing to pregnant women with hypertension has the potential to save resources.

The Association Between GFR Evaluated by Serum Cystatin C and Proteinuria During Pregnancy

Introduction

Physiological changes in pregnancy result in increased cardiac output and renal blood flow, with a consequential increase in proteinuria. Data from studies of the relationship between proteinuria caused by isolated proteinuria and glomerular filtration rate (GFR) are still limited. The objective of this study was to investigate the effects of isolated proteinuria on the cystatin C–based GFR in the third trimester of pregnancy.

Methods

Data were collected from pregnant women in their third trimester whose serum creatinine levels were normal. The GFR of each participant was measured using serum cystatin C levels, and proteinuria was measured using urine protein–creatinine ratios. The participants were divided into 3 groups according to their level of proteinuria: normal (<150 mg/d), physiological (150–300 mg/d), and gestational (>300 mg/d). Changes in GFR were recorded for each group.

Results

The study included 89 participants, of whom 66.3% had levels of proteinuria that did not differ from that of the normal population (<150 mg/d). The incidence of physiological and gestational proteinuria was 21.4% and 12.4%, respectively. The results demonstrate that proteinuria >101.50 mg/d was significantly associated with declined estimated glomerular filtration rate (eGFR) (r = –0.34, P = 0.01). The analysis found that proteinuria >491.27 mg/d led to a risk of GFR <90 ml/min with an odds ratio of 12.69, P = 0.02 when adjusted for systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index.

Conclusion

This study suggests that the term “physiological proteinuria” is a misnomer. When used in the traditional manner, creatinine level has inadequate sensitivity to estimate GFR in pregnant women. We found that there is a significant decline in GFR when urine protein > 101.5 mg/d, which could be an early biomarker for renal pathology rather than pregnancy physiology, suggesting that further workup and precaution is required.

Pregnancy in Chronic Kidney Disease: Need for Higher Awareness. A Pragmatic Review Focused on What Could Be Improved in the Different CKD Stages and Phases

Pregnancy is possible in all phases of chronic kidney disease (CKD), but its management may be difficult and the outcomes are not the same as in the overall population. The prevalence of CKD in pregnancy is estimated at about 3%, as high as that of pre-eclampsia (PE), a better-acknowledged risk for adverse pregnancy outcomes. When CKD is known, pregnancy should be considered as high risk and followed accordingly; furthermore, since CKD is often asymptomatic, pregnant women should be screened for the presence of CKD, allowing better management of pregnancy, and timely treatment after pregnancy. The differential diagnosis between CKD and PE is sometimes difficult, but making it may be important for pregnancy management. Pregnancy is possible, even if at high risk for complications, including preterm delivery and intrauterine growth restriction, superimposed PE, and pregnancy-induced hypertension. Results in all phases are strictly dependent upon the socio-sanitary system and the availability of renal and obstetric care and, especially for preterm children, of intensive care units. Women on dialysis should be aware of the possibility of conceiving and having a successful pregnancy, and intensive dialysis (up to daily, long-hours dialysis) is the clinical choice allowing the best results. Such a choice may, however, need adaptation where access to dialysis is limited or distances are prohibitive. After kidney transplantation, pregnancies should be followed up with great attention, to minimize the risks for mother, child, and for the graft. A research agenda supporting international comparisons is highly needed to ameliorate or provide knowledge on specific kidney diseases and to develop context-adapted treatment strategies to improve pregnancy outcomes in CKD women.

Outcome of pregnancy with new onset proteinuria and progression to pre-eclampsia: A retrospective analysis

OBJECTIVE

To examine maternal and neonatal outcomes of gestational proteinuria, and to identify maternal characteristics for progression to pre-eclampsia.

STUDY DESIGN

Retrospective cohort. Included all pregnant women who delivered between Jan 2014-Feb 2017 with new onset proteinuria in a single obstetric unit. Demographic, maternal and neonatal outcomes were compared.

RESULTS

Eighteen (25%) out of 73 women with new onset gestational proteinuria developed pre-eclampsia. The incidence of gestational proteinuria was 0.54%. Compared with women that remained normotensive, those that developed hypertension had delivery at earlier gestation (p = .02), increased risk of fetal growth restriction (p = .01) and lower newborn birthweight (p = .002). Maximal proteinuria and fetal growth restriction were independent factors associated with development of pre-eclampsia. In particular, high proteinuria level ≥ 2 g/d constitute a major predictor for progression (p = .03).

CONCLUSION

Increased vigilance for antenatal surveillance is important in women with gestational proteinuria as a substantial portion progress to pre-eclampsia. Serial growth scan and proteinuria assay are suggested to predict possible pre-eclampsia development.

Steroid Pulse Therapy for De Novo Minimal Change Disease During Pregnancy

BACKGROUND Nephrotic syndrome occurs very rarely, in only about 0.01%-0.02% of all pregnancies, and de novo minimal change disease during pregnancy is especially rare. Nephrotic syndrome and, especially, minimal change disease are highly responsive to steroids, and preterm labor may be avoidable if the maternal condition is improved with steroid therapy. Therefore, prompt diagnosis and proper management are critical to maternal and fetal outcome when severe proteinuria occurs during pregnancy. CASE REPORT A 30-year-old pregnant Japanese woman presented with systemic edema, oliguria, and severe proteinuria and hypoalbuminemia at 25 weeks of gestation, although she was normotensive. The patient had high urinary protein selectivity. Her illness was diagnosed as de novo nephrotic syndrome with high steroid responsiveness rather than pre-eclampsia. She began steroid pulse therapy the day after admission. Complete remission was confirmed after 3 weeks. The patient did not relapse during pregnancy and delivered a healthy male baby at 37 weeks of gestation. A renal biopsy at a relapse after delivery confirmed minimal change disease. CONCLUSIONS In pregnant women with de novo minimal change disease, serious maternal and/or fetal complications may occur if severe proteinuria and hypoalbuminemia are unabated for an extended time. Evaluation of urinary protein selectivity is noninvasive and useful for prediction of steroid responsiveness. Results of urinary protein selectivity can be obtained earlier than results of renal biopsy. Renal biopsy during pregnancy is not always necessary for initiation of steroid therapy. Rapid initiation of steroid pulse therapy may enable quicker achievement of remission and prevent serious perinatal complications.

Second-trimester urine nephrin:creatinine ratio versus soluble fms-like tyrosine kinase-1:placental growth factor ratio for prediction of preeclampsia among asymptomatic women

This prospective observational study compare urine nephrin:creatinine ratio (NCR, ng/mg) with serum soluble fms-like tyrosine kinase-1:placental growth factor ratio (FPR, pg/pg) for preeclampsia (PE) prediction among unselected asymptomatic pregnant women in 2^nd trimester. NCR and FPR were determined in 254 paired urine/blood samples collected simultaneously from 254 women at median gestational week (GW) 24 (range, 22–27) without hypertension or significant proteinuria in pregnancy (SPIP). Fifteen (5.9%) developed SPIP and hypertension at GW 34.0 (26.0–38.6) and 35.3 (27.6–38.6), respectively, and were diagnosed with PE at GW 35.7 (27.6–38.6). The 90^th percentile level determined in 239 women normotensive throughout pregnancy gave NCR (139) sensitivity and positive predictive values (PPV) of 60% (9/15) and 27% (9/33), while those for serum FPR (4.85) were 40% (6/15) and 20% (6/30), respectively. Relative risks (95%CI) of later PE were 10.0 (3.82–26.4; 27% [9/33] vs. 2.7% [6/221]) and 4.98 (1.91–13.0; 20% [6/30] vs. 4.0% [9/224]) for NCR-positive and FPR-positive women, respectively. Cut-offs suggested by ROC gave NCR (86.6) sensitivity and PPV of 87% (13/15) and 17% (13/79), and FPR (8.8) values of 40% (6/15) and 40% (6/15), respectively. Thus, 2^nd trimester NCR was superior to FPR for PE prediction.