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Development of prenatal lateralization: evidence from fetal mouth movements

Reissland, N.; Francis, B.; Aydin, E.; Mason, J.; Exley, K.

Development of prenatal lateralization: evidence from fetal mouth movements Thumbnail


B. Francis

E. Aydin

J. Mason

K. Exley


Background: Human lateralized behaviors relate to the asymmetric development of the brain. Research of the prenatal origins of laterality is equivocal with some studies suggesting that fetuses exhibit lateralized behavior and other not finding such laterality. Given that by around 22 weeks gestation the left cerebral hemisphere compared to the right is significantly larger in both male and female fetuses we expected that the right side of the fetal face would show more movement with increased gestation. This longitudinal study investigated whether fetuses from 24 to 36 weeks gestation showed increasing lateralized behaviours during mouth opening and whether lateralized mouth movements are related to fetal age, gender and maternal self-reported prenatal stress. Participants: Following ethical approval, fifteen healthy fetuses (8 girls) of primagravid mothers were scanned four times from 24-36-weeks gestation. Two types of mouth opening movements - upper lip raiser and mouth stretch - were coded in 60 scans for 10 minutes. Results: We modelled the proportion of right mouth opening for each fetal scan using a generalised linear mixed model, which takes account of the repeated measures design. There was a significant increase in the proportion of lateralized mouth openings over the period increasing by 11% for each week of gestational age (LRT change in deviance = 10.92, 1 df; p < 0.001). No gender differences were found nor was there any effect of maternally reported stress on fetal lateralized mouth movements. There was also evidence of left lateralization preference in mouth movement, although no evidence of changes in lateralization bias over time. This longitudinal study provides important new insights into the development of lateralized mouth movements from 24–36 weeks gestation.


Reissland, N., Francis, B., Aydin, E., Mason, J., & Exley, K. (2014). Development of prenatal lateralization: evidence from fetal mouth movements. Physiology & Behavior, 131, 160-163.

Journal Article Type Article
Acceptance Date Apr 14, 2014
Online Publication Date Apr 24, 2014
Publication Date May 1, 2014
Deposit Date Apr 24, 2014
Publicly Available Date Apr 24, 2014
Journal Physiology and Behavior
Print ISSN 0031-9384
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 131
Pages 160-163
Keywords Human fetal development, Lateralized fetal mouth movements, Maternal stress, 4-D scans.


Accepted Journal Article (472 Kb)

Copyright Statement
NOTICE: this is the author’s version of a work that was accepted for publication in Physiology & behavior. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Physiology & behavior, 131, 2014, 10.1016/j.physbeh.2014.04.035

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