Value of prenatal chromosomal microarray analysis (CMA) in isolated foetal growth restriction diagnosed before 26 weeks of gestation

Abstract

Aim. To evaluate the diagnostic yield of amniocentesis with quantitative fluorescent polymerase chain reaction (QF-PCR) and chromosomal microarray analysis (CMA) in pregnancies with apparently isolated at the time of pre-amniocentesis assessment early-onset foetal growth restriction (FGR) diagnosed before 26 weeks of gestation and to explore associations with perinatal outcomes.Material and methods. This retrospective cohort study was conducted at a tertiary perinatal centre in Poland. From 1655 amniocenteses performed between 2018 and 2023, we identified 31 singleton pregnancies with isolated FGR (EFW/AC <3rd percentile) before 26 weeks, excluding all cases with structural anomalies or major maternal confounders. All cases underwent QF-PCR and CMA. Descriptive statistics and group comparisons were performed.Results. Abnormal genetic results were found in 9/31 cases (yield 29.0%; 95% CI 14.2–48.0%), including 3 triploidies and 6 pathogenic/likely pathogenic CNVs CMA provided an incremental yield of 19.4% over QF-PCR alone. Mean gestational age at delivery was 32.4 weeks, and adverse perinatal outcomes occurred in 29% of cases.Conclusions. In isolated early-onset FGR before 26 weeks, QF-PCR combined with CMA achieved a high diagnostic yield of 29%. These findings support routine use of CMA in this high-risk subgroup and highlight the prognostic importance of genetic testing.