Early-Onset Fetal Growth Restriction: Causes and Evaluation

Genetic Causes

Chromosomal abnormalities account for approximately 6.4% of early-onset FGR cases, even without structural malformations, according to the American College of Obstetricians and Gynecologists 1, 3
Chromosomal microarray analysis (CMA) provides a 4-10% incremental diagnostic yield over standard karyotyping in fetuses with early-onset growth restriction without structural malformations, as recommended by the American College of Medical Genetics and Genomics 1, 3

Suboptimal perfusion of the maternal-placental circulation is the most common cause of early-onset FGR, accounting for 25-30% of all cases, as stated by the Society for Maternal-Fetal Medicine 2
Maternal hypertensive disease is present in 50% of early-onset FGR cases during pregnancy and 70% at delivery, making it one of the most important independent determinants of poor outcomes, according to the American Heart Association 5, 6

Cytomegalovirus (CMV) is the primary infectious etiology to evaluate in early-onset FGR, and PCR for CMV should be performed in women with unexplained FGR who elect diagnostic testing with amniocentesis, as recommended by the Centers for Disease Control and Prevention 7, 5

When early-onset FGR is diagnosed, a detailed obstetrical ultrasound examination should be performed to identify structural abnormalities, as suggested by the American Institute of Ultrasound in Medicine 2, 7, 5
Offer prenatal diagnostic testing with CMA when FGR is detected with fetal malformation, polyhydramnios, or both, or when unexplained isolated FGR is diagnosed at <32 weeks gestation, as recommended by the National Society of Genetic Counselors 1, 4, 7
Monitor closely for development of hypertensive disorders of pregnancy, as this complication is highly prevalent and significantly impacts outcomes, according to the American College of Obstetricians and Gynecologists 5, 6