Evaluation of genetic variants using chromosomal microarray analysis for fetuses with polyhydramnios

BACKGROUND: Polyhydramnios, the excessive accumulation of amniotic fluid, is associated with an elevated risk of abnormal karyotype, particularly aneuploidy. Studies focusing on chromosomal microarray analysis (CMA) in pregnancies with polyhydramnios are limited. The aim of this study is to evaluate the implications of pregnancy with polyhydramnios by CMA testing and routine karyotyping. METHODS: Data from 131 singleton and 17 twin pregnancies that underwent prenatal CMA testing due to polyhydramnios between May 2017 and May 2021 were reviewed. Enrolled cases were grouped into isolated polyhydramnios (N = 39) and non-isolated polyhydramnios (N = 111). Non-isolated group was further categorized as subgroup of soft markers (n = 59) and non-soft markers (n = 52). RESULTS: CMA revealed an additional 10 (6.7%) chromosomal aberrations with clinical significance in 9 fetuses from singleton pregnancies and 1 from a twin pregnancy. Six microdeletion/microduplication syndromes were observed, of which 4 were located on chromosome 17. The incremental yields of clinically significant CMA findings in non-isolated polyhydramnios was 8.1%, and the values in fetuses along with soft markers and non-soft markers were 5.1% and 11.5% (p > 0.05), respectively. Only one incidental finding related to neuropathy with liability to pressure palsies was detected from 39 fetuses with isolated polyhydramnios. CONCLUSIONS: Non-isolated polyhydramnios is associated with several microdeletion/microduplication syndromes, regardless of singleton or twin pregnancies. Our results suggest insufficient evidence to recommend CMA in pregnancies with isolated polyhydramnios. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12920-022-01224-w.