[Postnatal outcome from polyhydramnios without sonographic abnormalities]

Idiopathic polyhydramnios and postnatal outcomes of children: The role of exome sequencing

OBJECTIVES

The objective of our study was to evaluate the long-term outcome of children born from a pregnancy complicated by idiopathic polyhydramnios. The secondary objective was to investigate factors associated with adverse outcomes.

METHODS

We conducted a retrospective study in two prenatal diagnosis centers between January 1, 2009 and December 31, 2020. Inclusion criteria were pregnancies with a diagnosis of idiopathic polyhydramnios, defined by a deepest pocket greater than 8 cm, no detectable abnormality at ultrasound and a negative amniotic fluid assessment including karyotype, chromosomal microarray, biochemical assays (electrolytes and digestive enzymes), and viruses (parvovirus B19 and cytomegalovirus). One-year outcomes of these children were collected. The primary endpoint was adverse postnatal outcome, defined by at least one of the following criteria: stillbirth, neonatal death, or serious and incurable condition diagnosed in the first year of life.

RESULTS

Of the 245 women referred for isolated polyhydramnios, 73 were diagnosed with idiopathic polyhydramnios after prenatal investigations. The mean age at follow-up of children was 28 months (95% CI 20-36). An adverse outcome occurred in 25% of cases (18/73), with one stillbirth, two neonatal deaths, and 15 severe conditions diagnosed postnatally, including a rate of monogenic disorders of 8.2% (6/73). Pediatric follow-up was normal for 75% of the children (55/73), including a rate of 9% (5/55) of curable conditions. Repeated amnioreduction was independently associated with an adverse outcome.

CONCLUSION

Pregnant women with polyhydramnios should be informed of the increased risk of 25% of perinatal mortality and serious conditions diagnosed after birth.

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.