Fetal brain MRI in polyhydramnios: is it justified?

Disparities Between Prenatal Ultrasound and Autopsy Findings in Pregnancies Resulting in Fetal Loss

OBJECTIVES

This retrospective study aimed to assess disparities between prenatal ultrasound and autopsy findings in pregnancies that resulted in fetal loss, and to evaluate the diagnostic performance of prenatal ultrasound using postmortem examinations as a gold standard.

METHODS

Our study included 136 autopsy cases following a fetal loss that occurred at our tertiary medical center for 8 years. A comparison between the prenatal ultrasound and autopsy findings was made, and all cases were classified according to the degree of agreement. The diagnostic performance of prenatal ultrasound was calculated at the level of organ system and specific malformations.

RESULTS

The primary sonographic diagnosis was confirmed in 91.9% of the cases (n = 125). General agreement was highest among central nervous system (CNS), cardiovascular and musculoskeletal systems (85.7%, n = 36, 18, and 12, respectively) and lowest among facial, multiple anomalies, genitourinary and gastrointestinal systems (50.0%, 74.3%, 78.6%, and 80.0%, n = 2, 26, 11, and 4, respectively). The sensitivity of ultrasound was highest in the CNS (93.2%) and musculoskeletal (87.0%) and lowest in the facial (32.3%) and pulmonary (13.0%) systems. Specifically, low diagnostic rates were noted in detecting ventriculomegaly, valvular anomalies, renal dysplasia, spleen and adrenal anomalies, and digital and facial defects.

CONCLUSIONS

Our study observed an overall high agreement between prenatal ultrasound and autopsy while contributing to our comprehensive understanding of its strengths and limitations across various types of organ systems and specific malformations.

Window to the Womb: Amniotic Fluid and Postnatal Outcomes

Amniotic fluid volumes are tightly regulated, and amniotic fluid derangement can indicate maternal complications or fetal abnormalities. Ultrasound estimate of amniotic fluid provides a tool to evaluate the maternal-fetal-placental interface in real-time. Oligohydramnios and polyhydramnios are associated with adverse maternal and neonatal outcomes. Oligohydramnios is associated with adverse maternal and neonatal outcomes including cesarean delivery, operative vaginal delivery, induction of labor, postpartum hemorrhage, small for gestational age neonate, intrauterine demise, neonatal death, NICU admission, and APGAR less than 7 at. 5 minutes of life Polyhydramnios is associated with adverse outcomes including cesarean delivery, induction of labor, placental abruption, shoulder dystocia, cord prolapse, postpartum hemorrhage, intrauterine fetal demise, NICU admission, neonatal death, APGAR less than 7 at 5 minutes of life, large for gestational age neonate, and respiratory distress syndrome. Therefore, Amniotic fluid should be evaluated when maternal or fetal well-being is in question.

Performance of diagnostic ultrasound to identify causes of hydramnios

INTRODUCTION

We aimed to assess the diagnostic yield of ultrasonography in the identification of the etiology of hydramnios, and the added value of MRI or amniocentesis.

METHODS

We conducted a single-center retrospective study including pregnancies with confirmed hydramnios (defined as deepest pocket ≥8 cm) between January 2013 and May 2017. Twin pregnancies, secondary hydramnios discovered after the diagnosis of a causal pathology, and pregnancies of unknown outcome were excluded. All pregnancies underwent a targeted scan, and selected cases underwent MRI or amniocentesis.

RESULTS

A total of 158 patients with confirmed hydramnios were included. Hydramnios was associated with a fetal pathology in 37 cases (23.4%), with diabetes in 39 (24.6%), isolated macrosomia in 16 (10.1%), and considered idiopathic in 66 (41.7%). Ultrasonography established a diagnosis of the underlying pathology in 73% of cases. Amniocentesis was done in 31 cases (20%) and it allowed diagnosis of chromosome anomalies, esophageal atresia, myotonic dystrophy congenital type, Prader-Willi syndrome, and Bartter syndrome. MRI was done in 15 cases (10%) and it allowed one additional diagnosis of esophageal atresia. The diagnostic yields of MRI and amniocentesis were 91.7% and 95.2%, respectively. There were five false positive diagnoses at ultrasonography, and one false positive diagnosis at MRI.

CONCLUSION

Hydramnios can be associated with a wide variety of underlying pathologies. Diagnostic ultrasound can attain a diagnosis in the majority of cases. Amniocentesis offers a valuable complementary assessment.