Fetal Sleep: A Cross-Species Review of Physiology, Measurement, and Classification

Area of Science:

• Neuroscience
• Developmental Biology
• Obstetrics

Background:

• Fetal sleep is vital for neurodevelopment but remains underexplored.
• Understanding fetal sleep offers insights into brain maturation and detecting neurological compromise.
• Current knowledge relies on decades of research across species and methodologies.

Purpose of the Study:

• To synthesize existing research on fetal sleep characteristics, development, and regulation.
• To compare sleep patterns in humans and animal models, noting differences and analogs.
• To examine computational methods for fetal sleep-state classification.

Main Methods:

• Comprehensive literature review spanning over eight decades.
• Comparison of invasive (animal models) and non-invasive (human) techniques.
• Analysis of computational approaches, including rule-based and deep learning methods.

Main Results:

• Fetal sleep patterns exhibit species-specific characteristics with identifiable analogs.
• Both traditional and advanced computational methods are used for sleep-state classification.
• Intrauterine conditions like hypoxia and fetal growth restriction significantly disrupt fetal sleep.

Conclusions:

• A comprehensive understanding of fetal sleep is essential for prenatal neurodevelopmental assessment.
• Developing objective, multimodal, non-invasive monitoring technologies is a key future direction.
• Improved fetal sleep monitoring can facilitate early diagnosis and intervention in prenatal care.