Fetal growth restriction at the limits of viability

Area of Science:

• Perinatology
• Fetal Medicine
• Neonatology

Background:

• Small-for-gestational age (SGA) and intrauterine growth restriction (IUGR) are significant concerns in high-risk pregnancies.
• These conditions are associated with increased perinatal morbidity and mortality.
• Distinguishing the primary cause of poor fetal outcome is crucial for effective management.

Purpose of the Study:

• To review the outcomes of fetuses with early small-for-gestational age and/or intrauterine growth restriction.
• To identify the primary etiological factors contributing to poor fetal outcomes in these cases.
• To provide guidance on the optimal timing for initiating active management of intrauterine growth restriction.

Main Methods:

• Literature review of studies focusing on early-onset fetal growth restriction.
• Analysis of outcomes in small-for-gestational age fetuses compared to appropriate-for-gestational age fetuses.
• Evaluation of the roles of intrauterine malnutrition and hypoxemia in fetal development.

Main Results:

• Fetuses experiencing early small-for-gestational age and/or intrauterine growth restriction exhibit significantly poorer outcomes compared to appropriately grown fetuses.
• Intrauterine malnutrition is identified as the predominant cause of adverse outcomes, outweighing the impact of hypoxemia.
• The data suggests that active management for intrauterine growth restriction should be initiated at or after 26 weeks of gestation.

Conclusions:

• Early-onset fetal growth restriction poses substantial risks to fetal well-being.
• Addressing intrauterine malnutrition is key to improving outcomes for affected fetuses.
• A gestational age threshold of 26 weeks is proposed for commencing active management of intrauterine growth restriction.