The role of waddling gait in balance control during pregnancy.

Background: Pregnant people experience many physical changes which might affect their walking pattern. Waddling gait is a common gait pattern pregnant individuals adopt. It is unknown whether waddling gait is a sign of poor balance or a protective mechanism against loss of balance, so the aim of this study was to understand why some pregnant individuals adopt this gait pattern.

Methods: We assessed twenty-three pregnant individuals longitudinally in 4-week intervals between 18 and 34 weeks of gestation. Participants completed a quiet standing balance trial and a walking trial. We measured spatiotemporal variables and body center of mass motion, from which we derived measures of balance and gait energetics. Forward-step multiple linear regression analyses were used to explore the correlation between step width (as a measure of waddling) and the other variables.

Results: We found a positive correlation between change in step width average and change in lateral motion of the center of mass during walking (R=0.624, P<0.001) and change in step width standard deviation and change in minimum center of gravity distance to the lateral border (R=0.339, p=0.004), suggesting wider steps help recapture balance during pregnancy. Surprisingly, no significant relationship was found between change in step width and changes in energy recovery (p=0.341) or mechanical work (p=0.482), indicating that taking wider steps is not inefficient. A negative correlation between change in step width and change in standing anteroposterior center of mass motion (R=0.315, p=0.005) suggests better balance control among people that adopt a waddling gait pattern.

Significance: This study suggests that waddling gait is a protective mechanism during pregnancy. Clinicians and prosthetists can use this insight to promote step width during walking among pregnant individuals to increase their safety.