RESUMO
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.