Early-onset fetal growth restriction (FGR) requires careful clinical evaluation to identify the underlying cause. When a fetus shows severe growth restriction before 29 weeks, doctors must decide on the necessity of invasive genetic testing. Recent evidence suggests that placental insufficiency markers significantly improve the assessment of early-onset FGR risk. Specifically, the ratio of soluble fms-like tyrosine kinase-1 to placental growth factor helps distinguish between placental and genetic etiologies.
Historically, clinicians utilized the sFlt-1/PlGF ratio mainly for predicting preeclampsia. However, this study demonstrates its broader utility in fetal medicine. A low ratio suggests that the growth restriction is likely not caused by placental dysfunction. Consequently, the probability of an underlying pathogenic genetic abnormality increases in these cases. Therefore, the absence of placental insufficiency should prompt more comprehensive genetic investigations.
Determining Early-onset FGR Risk through Biomarkers
The retrospective analysis included singleton pregnancies with an estimated fetal weight at or below the 3rd percentile. Researchers identified cases where chromosomal microarray or whole-exome sequencing detected pathogenic abnormalities. They found that patients with a low sFlt-1/PlGF ratio had a higher frequency of non-chromosomal genetic conditions. In contrast, those with high ratios typically exhibited signs of placental-mediated disease.
Moreover, this biomarker-led approach provides a more nuanced strategy for prenatal counseling. Instead of performing invasive tests on every patient, doctors can prioritize those with low placental markers. This selective testing strategy optimizes medical resources and provides clearer diagnostic paths for families. Furthermore, identifying a genetic cause early allows for better management of the pregnancy and preparation for neonatal care.
Frequently Asked Questions
Q1: Why is the sFlt-1/PlGF ratio important for evaluating growth restriction?
This ratio helps clinicians determine if the growth restriction stems from placental failure or if other factors, such as genetic anomalies, are more likely responsible.
Q2: When should a doctor consider whole-exome sequencing in FGR cases?
A doctor should strongly consider comprehensive genetic testing like whole-exome sequencing when early-onset FGR occurs without evidence of placental insufficiency markers.
References
- Armengol-Alsina M et al. Placental insufficiency markers to assess the risk of non-chromosomal genetic conditions in early-onset fetal growth restriction. Ultrasound Obstet Gynecol. 2026 Mar 30. doi: 10.1002/uog.70211. PMID: 41906976.
- Ghi T et al. ISUOG Practice Guidelines: diagnosis and management of small-for-gestational-age fetus and fetal growth restriction. Ultrasound Obstet Gynecol. 2018.
- Stepan H et al. Implementation of the sFlt-1/PlGF ratio for prediction and diagnosis of pre-eclampsia in singleton pregnancy. Ultrasound Obstet Gynecol. 2015.