Moderate Diagnostic Yield of Exome Sequencing in Fetal Growth Restriction: Retrospective Insights

Objective To determine whether invasive genetic testing should be systematically proposed in cases of FGR. Methods Descriptive retrospective study of 159 FGR cases (defined by an estimated fetal growth < 3rd percentile, regardless of Doppler findings) managed at the Toulouse Fetal Medicine Center (TFMC) during 2022–2023. Results Mean gestational age at diagnosis was 23.7 weeks. Head circumference < 3rd percentile was observed in 35% of cases, hemodynamic signs in 57%, and oligohydramnios in 11%. Invasive testing was performed in 56% ( n = 89) of cases, with a diagnostic yield in cases with hemodynamic signs of 19% for genetic syndromes (whether chromosomal or monogenic), which dropped to 11% ( n = 8) in isolated FGR. Postnatally, 50% ( n = 67) of cases were attributed to placental causes, 31% ( n = 41) to genetic disorders (of which 41% had a negative prenatal genetic workup), while 13% remained unexplained. Placental causes were most often due to chronic maternal vascular malperfusion (72%). Conclusion Findings support the systematic offer of exome sequencing in second‐trimester FGR, regardless of whether it is isolated, associated with head circumference < 3rd percentile, or with abnormal hemodynamic profiles.