Prenatally diagnosed lower urinary tract obstruction: A 15-year experience at two tertiary centers in Japan

Trends in Management of Fetuses with Suspected Lower Urinary Tract Obstruction (LUTO): A High-Risk Fetal and Pediatric Center Experience in a Universal-Access-to-Care System

INTRODUCTION

 Neonates with lower urinary tract obstruction (LUTO) experience high morbidity and mortality associated with the development of chronic kidney disease. The prenatal detection rate for LUTO is less than 50%, with late or missed diagnosis leading to delayed management and long-term sequelae in the remainder. We aimed to explore the trends in prenatal detection and management at a high-risk fetal center and determine if similar trends of postnatal presentations were noted for the same period.

METHODS

 Prenatal and postnatal LUTO databases from a tertiary fetal center and its associated pediatric center between 2009 and 2021 were reviewed, capturing maternal age, gestational age (GA) at diagnosis, and rates of termination of pregnancy (TOP). Time series analysis using autocorrelation was performed to investigate time trend changes for prenatally suspected and postnatally confirmed LUTO cases.

RESULTS

 A total of 161 fetuses with prenatally suspected LUTO were identified, including 78 terminations. No significant time trend was found when evaluating the correlation between time periods, prenatal suspicion, and postnatal confirmation of LUTO cases (Durbin-Watson [DW] = 1.99, p = 0.3641 and DW = 2.86, p = 0.9113, respectively). GA at referral was 20.0 weeks (interquartile range [IQR] 12, 35) and 22.0 weeks (IQR 13, 37) for TOP and continued pregnancies (p < 0.0001). GA at initial ultrasound was earlier in terminated fetuses compared to continued (20.0 [IQR 12, 35] weeks vs. 22.5 [IQR 13, 39] weeks, p < 0.0001). While prenatal LUTO suspicion remained consistently higher than postnatal presentations, the rates of postnatal presentations and terminations remained stable during the study years (p = 0.7913 and 0.2338), as were GA at TOP and maternal age at diagnosis (p = 0.1710 and 0.1921).

CONCLUSION

 This study demonstrated that more severe cases of LUTO are referred earlier and are more likely to undergo TOP. No significant trend was detected between time and prenatally suspected or postnatally confirmed LUTO, highlighting the need for further studies to better delineate factors that can increase prenatal detection.

Outcomes of fetal lower urinary tract obstruction based on timing of oligohydramnios onset

OBJECTIVE

Fetal Lower Urinary Tract Obstruction (LUTO) is associated with oligohydramnios and significant fetal morbidity, resulting in poor lung development and perinatal death. However, oligohydramnios may develop at different gestational periods, and the impact of timing on fetal outcomes remains unknown. Our objective was to characterize the impact onset of oligohydramnios had on prenatal outcomes.

METHODS

This study is a retrospective cohort study of all patients with a prenatal diagnosis of LUTO at our tertiary referral center from 2014 to 2023. All patients underwent detailed ultrasonography and interdisciplinary counseling and were subsequently delivered at our institution. Data were obtained from electronic medical records and complete extraction was required for final inclusion.

RESULTS

During the study time period, 93 patients met inclusion criteria of which 68 (73.1%) developed oligohydramnios during their pregnancy. 63 (93%) of these pregnancies resulted in livebirths with 28 (41.1%) perinatal deaths. Onset of oligohydramnios was earlier in pregnancies with perinatal death (23 vs. 28 weeks, p = 0.004) and associated with pulmonary hypoplasia.

CONCLUSIONS

Our data show the impact of oligohydramnios timing in pregnancy on pulmonary hypoplasia and ultimately perinatal death. This allows for detailed patient counseling on the impact oligohydramnios may have on pregnancies by the gestational age of onset.

New challenges of fetal therapy in Japan

Aim

To review new challenges of fetal therapy in Japan after the establishment of four existing fetal therapies as standard prenatal care with National Health Insurance coverage over the past 20 years.

Methods

Reported studies and our current research activities related to four fetal therapies newly performed in Japan were reviewed.

Results

Fetoscopic endoluminal tracheal occlusion (FETO) for congenital diaphragmatic hernia (CDH) aims to occlude the trachea using a detachable balloon to promote lung growth. Following the recent successful completion of an international randomized controlled trial for CDH, in which we participated, FETO is offered for severe left CDH to perform balloon insertion at 27–29 weeks and removal at 34 weeks of gestation. Fetal cystoscopy (FC) for low urinary tract obstruction was introduced to overcome the demerits of vesicoamniotic shunting. FC may provide a proper diagnosis by visual observation of the urethra and physiological treatment of the posterior urethral valve. The effectiveness of open fetal surgery for myelomeningocele (MMC), direct surgery with laparotomy and hysterotomy, for ameliorating hindbrain herniation and the motor function was demonstrated, but it was also associated with substantial maternal and fetal risks. Fetal aortic valvuloplasty (FAV), ultrasound‐guided fetal aortic balloon dilation for critical aortic stenosis with evolving hypoplastic left heart syndrome may improve left heart development and maintain biventricular circulation. Feasibility and safety studies for FC, MMC open fetal surgery, and FAV are currently ongoing.

Conclusions

Clinical research on FETO, FC, MMC open fetal surgery, and FAV has proceeded with careful preparations in Japan.