Static trunk posture in sitting and standing during pregnancy and early postpartum

To investigate the postural alignment of the upper body in the sagittal plane during sitting and standing postures as pregnancy progressed and then in the postpartum period.

Longitudinal, repeated-measures design.

Biomechanics laboratory in an Australian university.

A volunteer convenience sample of 9 primiparous and multiparous women and 12 nulliparous women serving as a control group.

Not applicable.

Subjects were filmed while sitting and during quiet standing at intervals throughout pregnancy and at 8 weeks postpartum. A repeated-measures analysis of variance was used to assess systematic changes in the alignment of the pelvic, thoracic, and head segments, and the thoracolumbar and cervicothoracic spines. Student t tests were used to compare the postpartum and nulliparous control groups.

There was no significant effect of pregnancy on the upper-body posture, although there was a tendency in some subjects for a flatter thoracolumbar spinal curve in sitting as pregnancy progressed. Postpartum during standing, the pelvic segment had a reduced sagittal plane anterior orientation, and the thoracolumbar spine was less extended, indicating a flatter spinal curve compared with the control group.

There was no significant effect of pregnancy on upper-body posture during sitting and standing, although individuals varied in their postural response. A flatter spinal curve was found during standing postpartum.