The Role of Fetal MRI in Management of Polyhydramnios: Findings From a Fetal Care Center [ID: 1378023

Abstract

INTRODUCTION: Polyhydramnios, affecting 1–2% of pregnancies, is frequently associated with congenital anomalies. Prenatal ultrasound may identify potential etiologies for polyhydramnios and associated anomalies but has limitations particularly with regard to gastrointestinal imaging. There are no guidelines for use of fetal MRI (fMRI) in the setting of polyhydramnios. METHODS: The medical records of all patients referred to Cleveland Clinic’s Fetal Care Center between 2015 and 2021 were reviewed. Singleton pregnancies with amniotic fluid index (AFI)≥24 cm who underwent fMRI were included. Prenatal diagnoses made by ultrasound and fMRI were compared to postnatal diagnosis and potential etiologies for polyhydramnios. RESULTS: Fifty-eight patients with polyhydramnios received an fMRI, of which 26.6% (16/58) had a new diagnosis not detected by prior prenatal ultrasounds. Among cases where fMRI resulted in a new diagnosis, the majority were neurological 25% (4/16) or genitourinary anomalies 25% (4/16); 12.5% (2/16) were considered causative of polyhydramnios. Among patients with a new diagnosis on fMRI, 25% (4/16) had no abnormalities identified by prenatal ultrasound. Fetal MRI confirmed ultrasound diagnoses in 76.2% (32/42) of cases. There was no difference in average AFI between patients who were and were not found to have a new diagnosis on fMRI (33.1 versus 33.0, P=.47). CONCLUSION: In patients presenting to a fetal care center with polyhydramnios, addition of fMRI to prenatal ultrasound identified new anomalies in 26.6% of cases. Fetal MRI should be considered an adjunct to prenatal ultrasound in evaluation of pregnancies complicated by polyhydramnios to improve prenatal diagnosis of structural anomalies, prenatal counseling, and perinatal management.