Pulmonary hypoplasia correlates with the length of anhydramnios in patients with early pregnancy renal anhydramnios (EPRA)

Case Report: A rare case of renal failure secondary to in utero megalourethra

Background

Megalourethra is a rare congenital condition marked by dilation and elongation of the penile urethra, resulting from hypoplasia of either the corpus spongiosum or corpus cavernosa.

Case presentation

We describe a novel case of a male infant prenatally diagnosed with megalourethra who subsequently developed rapid-onset anhydramnios and advanced renal failure.

Conclusion

Unlike previously described cases, this case is unique due to the patient's abrupt progression to anhydramnios at 34 weeks and 5 days, despite having normal amniotic fluid levels prior to that. With late-onset anhydramnios, the severity of renal dysfunction was unexpected. Proximal urethrostomy requires further assessment as a potential intervention to successfully bypass the megalourethra and prevent infection. Long-term management is expected to include dialysis as a bridge to transplantation. Multiple corrective urological surgeries will be required to repair the urethra and restore penile function. Timely prenatal diagnosis of megalourethra or renal anomalies is essential for predicting long-term prognosis, as these conditions can lead to significant postnatal complications.

Amniotic fluid: its role in fetal development and beyond

Amniotic fluid is a complex biological medium that surrounds the fetus and offers not only mechanical protection but also provides nutrition and plays a critical role in normal fetal growth, organogenesis, and potentially fetal programming. Despite its importance, the biology of amniotic fluid has been understudied because of ethical and technical challenges in obtaining amniotic fluid samples from healthy human pregnancies, translational limitations of animal models to humans due to species-specific differences. Recent progress in understanding its dynamic physiology, composition, and clinical applications has advanced prenatal care and facilitated improved diagnostic and therapeutic strategies. As research continues to elucidate the complexities and evolutionary function of amniotic fluid, its increasingly recognized role in maternal-fetal medicine and its potential to transform clinical practice will only become more evident. The purpose of this review is to underscore the key roles of amniotic fluid in shaping fetal development and therapeutic potential.

Long-Term Outcomes, Including Fetal and Neonatal Prognosis, of Renal Oligohydramnios: A Retrospective Study over 22 Years

OBJECTIVE

To assess the long-term outcome of renal oligohydramnios and risk factors for fetal, neonatal, and postneonatal death.

STUDY DESIGN

This retrospective cohort study included fetuses with prenatally detected renal oligohydramnios between 2002 and 2023. Patients who were lost to follow-up were excluded. Fetal, neonatal, and long-term outcomes were evaluated, and their risk factors were analyzed.

RESULTS

Of 131 fetuses with renal oligohydramnios, 46 (35%) underwent a termination of pregnancy, 11 (8%) had an intrauterine fetal death, 26 (20%) had a neonatal death, nine (7%) had a postneonatal death, and 39 (30%) survived. Logistic regression analyses showed that an earlier gestational age at onset (OR 1.16, 95% CI 1.01-1.37) was significantly associated with intrauterine fetal death; anhydramnios (OR 12.7, 95% CI 1.52-106.7) was significantly associated with neonatal death as a prenatal factor. Although neonatal survival rates for bilateral renal agenesis, bilateral multicystic dysplastic kidney (MCDK), and unilateral MCDK with contralateral renal agenesis were lower than for other kidney diseases, 1 case of bilateral renal agenesis and two of bilateral MCDK survived with fetal intervention. Kaplan-Meier overall survival rates were 57%, 55%, and 51% for 1, 3, and 5 years, respectively. In the Cox proportional hazards model, birth weight <2000 g (hazard ratio 7.33, 95% CI 1.48-36.1) and gastrointestinal comorbidity (hazard ratio 4.37, 95% CI 1.03-18.5) were significant risk factors for postneonatal death.

CONCLUSION

Long-term survival following renal oligohydramnios is a feasible goal and its appropriate risk assessment is important.

Delivery Room Management of Infants with Surgical Conditions

Delivery room resuscitation of infants with surgical conditions can be complex and depends on an experienced and cohesive multidisciplinary team whose performance is more important than that of any individual team member. Existing resuscitation algorithms were not developed for infants with congenital anomalies, and delivery room resuscitation is largely dictated by expert opinion extrapolating physiologic expectations from infants without anomalies. As prenatal diagnosis rates improve, there is an increased ability to plan for the unique delivery room needs of infants with surgical conditions. In this review, we share expert opinion, including our center's delivery room management for neonatal noncardiac surgical conditions, and highlight knowledge gaps and the need for further studies and evidence-based practice to be incorporated into the delivery room care of infants with surgical conditions. Future research in this area is essential to move from an expert-based approach to a data-driven approach to improve and individualize delivery room resuscitation of infants with surgical conditions.

Comparison of Serial Amnioinfusion Strategies for Isolated Early-Onset Fetal Renal Anhydramnios

INTRODUCTION

The optimal protocol for serial amnioinfusions to maintain amniotic fluid in pregnancies with early-onset fetal renal anhydramnios before 22 weeks is not known. We compared the performance of two different approaches.

METHODS

A secondary analysis was conducted of serial amnioinfusions performed by a single center during the external pilot and feasibility phases of the Renal Anhydramnios Fetal Therapy (RAFT) trial. During the external pilot, higher amnioinfusion volumes were given less frequently; in the feasibility study, smaller volume amnioinfusions were administered more frequently. Procedural details, complications, and obstetric outcomes were compared between the two groups using Pearson's χ2 or Fisher's exact tests for categorical variables and Student's t tests or Wilcoxon rank-sum tests for continuous variables. The adjusted association between procedural details and chorioamniotic separation was obtained through a multivariate repeated measure logistic regression model.

RESULTS

Eleven participants underwent 159 amnioinfusions (external pilot: 3 patients, 21 amnioinfusions; feasibility: 8 patients, 138 amnioinfusions). External pilot participants had fewer amnioinfusions (7 vs. 19.5 in the feasibility group, p = 0.04), larger amnioinfusion volume (750 vs. 500 mL, p < 0.01), and longer interval between amnioinfusions (6 [4-7] vs. 4 [3-5] days, p < 0.01). In the external pilot, chorioamniotic separation was more common (28.6% vs. 5.8%, p < 0.01), preterm prelabor rupture of membranes (PPROM) occurred sooner after amnioinfusion initiation (28 ± 21.5 vs. 75.6 ± 24.1 days, p = 0.03), and duration of maintained amniotic fluid between first and last amnioinfusion was shorter (38 ± 17.3 vs. 71 ± 19 days, p = 0.03), compared to the feasibility group. While delivery gestational age was similar (35.1 ± 1.7 vs. 33.8 ± 1.5 weeks, p = 0.21), feasibility participants maintained amniotic fluid longer.

CONCLUSION

Small volume serial amnioinfusions performed more frequently maintain normal amniotic fluid volume longer because of delayed occurrence of PPROM.

Neonatal Survival After Serial Amnioinfusions for Bilateral Renal Agenesis: The Renal Anhydramnios Fetal Therapy Trial

Importance

Early anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival.

Objective

To assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks' gestation to mitigate lethal pulmonary hypoplasia.

Design, Setting, and Participants

Prospective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies.

Exposure

Enrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks' gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age.

Main Outcomes and Measures

The primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement.

Results

The trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks' gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks).

Conclusions and Relevance

Serial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden.

Trial Registration

ClinicalTrials.gov Identifier: NCT03101891.

The amniotic fluid proteome changes across gestation in humans and rhesus macaques

Amniotic fluid is a complex biological medium that offers protection to the fetus and plays a key role in normal fetal nutrition, organogenesis, and potentially fetal programming. Amniotic fluid is also critically involved in longitudinally shaping the in utero milieu during pregnancy. Yet, the molecular mechanism(s) of action by which amniotic fluid regulates fetal development is ill-defined partly due to an incomplete understanding of the evolving composition of the amniotic fluid proteome. Prior research consisting of cross-sectional studies suggests that the amniotic fluid proteome changes as pregnancy advances, yet longitudinal alterations have not been confirmed because repeated sampling is prohibitive in humans. We therefore performed serial amniocenteses at early, mid, and late gestational time-points within the same pregnancies in a rhesus macaque model. Longitudinally-collected rhesus amniotic fluid samples were paired with gestational-age matched cross-sectional human samples. Utilizing LC-MS/MS isobaric labeling quantitative proteomics, we demonstrate considerable cross-species similarity between the amniotic fluid proteomes and large scale gestational-age associated changes in protein content throughout pregnancy. This is the first study to compare human and rhesus amniotic fluid proteomic profiles across gestation and establishes a reference amniotic fluid proteome. The non-human primate model holds promise as a translational platform for amniotic fluid studies.

Assessment of Amniotic Fluid Volume in Pregnancy

Amniotic fluid (AF) is an integral part of the fetal environment and is essential for fetal growth and development. Pathways of AF recirculation include the fetal lungs, swallowing, absorption through the fetal gastrointestinal tract, excretion through fetal urine production, and movement. In addition to being a marker for fetal health, adequate AF is necessary for fetal lung development, growth, and movement. The role of diagnostic imaging is to provide a detailed fetal survey, placental evaluation, and clinical correlation with maternal conditions to help identify causes of AF abnormalities and thereby enable specific therapy. Oligohydramnios prompts evaluation for fetal growth restriction as well as genitourinary issues, including renal agenesis, multicystic dysplastic kidneys, ureteropelvic junction obstruction, and bladder outlet obstruction. Premature preterm rupture of membranes should also be clinically excluded as a cause of oligohydramnios. Clinical trials evaluating amnioinfusion are underway as a potential intervention for renal causes of oligohydramnios. Most cases of polyhydramnios are idiopathic, with maternal diabetes being a common cause. Polyhydramnios prompts evaluation for fetal gastrointestinal obstruction and oropharyngeal or thoracic masses, as well as neurologic or musculoskeletal anomalies. Amnioreduction is performed only for maternal indications such as symptomatic polyhydramnios causing maternal respiratory distress. Polyhydramnios with fetal growth restriction is paradoxical and can occur with maternal diabetes and hypertension. When these maternal conditions are absent, this raises concern for aneuploidy. The authors describe the pathways of AF production and circulation, US and MRI assessment of AF, disease-specific disruption of AF pathways, and an algorithmic approach to AF abnormalities. ^©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.