Utility of chromosomal microarray analysis for the exploration of isolated and severe fetal growth restriction diagnosed before 24 weeks' gestation

Objective This study aimed to evaluate the utility of chromosomal microarray analysis (CMA), for the genetic exploration of isolated and severe intrauterine growth restriction (IUGR) diagnosed before 24 weeks gestation (WG). Methods This retrospective study included singleton fetuses diagnosed with severe IUGR without structural anomalies before 24 WG referred between 2013 and 2021 who underwent prenatal genetic analysis. IUGR was defined by estimated fetal weight <= 3rd centile for gestational age. Genetic analysis, including QF-PCR and CMA, was systematically offered as part of the etiologic evaluation. Results Of 101 referred fetuses, CMA and QF-PCR were performed in 67 fetuses. Among these 67 cases, a total of 10.5% (7/67) chromosomal abnormalities were detected. CMA detected three pathogenic copy number variants (CNV) (3/67, 4.5%) and three variants of unknown signification (VUS) (3/67, 4.5%). Karyotype detected one chromosomal abnormality. All of the QF-PCR were normal. Two fetuses with pathogenic CNV shows Doppler abnormalities. Conclusion Our study found that in fetuses with severe, isolated, and very early-onset growth restriction, the rate of pathogenic CNV detected by CMA was 4.5%. Although this cohort is too small to draw a definitive conclusion, the presence of Doppler abnormalities couldn't exclude the possibility of genetic abnormalities.