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Smiles in the fetal period
Fumito Kawakami1, Takumi Yanaihara
1Japan Society for the Promotion of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033, Japan. fumito@valdes.titech.ac.jp
Infant Behavior & Development
|June 23, 2012
Summary
Fetal smiling, observed via four-dimensional ultrasonography, occurs frequently and lasts longer than in full-term newborns. These findings suggest fetal smiles may not stem from social interactions.
Area of Science:
- Fetal Development
- Neonatal Behavior
- Ultrasonography
Background:
- Spontaneous smiles in neonates have been studied, but fetal smiling remains less understood.
- Previous research suggests differences in smile duration between preterm and full-term neonates.
Purpose of the Study:
- To intensively collect and analyze fetal smiles using advanced ultrasonography.
- To compare the duration of fetal smiles with spontaneous smiles in preterm and full-term neonates.
Main Methods:
- Observation of 568 fetuses using four-dimensional ultrasonography.
- Selection of 31 fetuses exhibiting smiles between 156 and 214 days of conceptual age.
- Recording and analysis of 51 fetal smiles over 62 minutes.
Main Results:
- The average duration of fetal smiles was 3.21 seconds.
- Fetal smile duration was not significantly different from preterm neonates but was significantly longer than full-term neonates.
- Fetuses exhibited a high frequency of smiles during the observation period.
Conclusions:
- Fetal smiling is a frequent behavior that warrants further investigation.
- The duration of fetal smiles suggests they are not solely a result of social effects.
- These findings prompt a reconsideration of the meaning and origins of spontaneous smiles.
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