Pelvic alignment changes during the perinatal period.

BACKGROUND

The function of the pelvic bones is to transfer load generated by body weight. Proper function of the pelvic bones can be disturbed by alignment changes that occur during pregnancy. Further, misalignment of the pelvic bones can lead to pain, urinary incontinence, and other complications. An understanding of the timing and nature of pelvic alignment changes during pregnancy may aid in preventing and treating these complications.

OBJECTIVE

To investigate the changes in pelvic alignment during pregnancy and one month after childbirth.

METHODS

This is a prospective, longitudinal cohort study. Pelvic measurements were obtained for 201 women at 12, 24, 30, and 36 weeks of pregnancy, and 1 month after childbirth. The anterior and posterior width of the pelvis (the distance between the bilateral anterior superior iliac spines and the bilateral posterior superior iliac spines), the anterior pelvic tilt, and pelvic asymmetry (the mean left and right pelvic tilt degrees and the bilateral difference of the anterior pelvic tilt) were measured. For the change in pelvic alignment, a Friedman test was conducted to determine any significant difference in the measurements over time.

RESULTS

The anterior and posterior width of the pelvis became significantly wider with pregnancy progress and the anterior width of the pelvis at 1 month after childbirth remained wider than that at 12 weeks of pregnancy (p < 0.001). The anterior pelvic tilt increased during pregnancy and decreased after childbirth (p < 0.05).

CONCLUSION

Some changes in pelvic alignment occur continuously during the perinatal period. Changes in the anterior width of the pelvis are not recovered at one month post-childbirth. Understanding these perinatal changes may help clinicians avert complications due to pelvic misalignment.

Déclaration de conflit d'intérêts

Some of authors are employed by a commercial company: Kishokai Medical Corporation. However, the funder only provided support in the form of salaries for authors [FU, HH and MY], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Moreover, this does not alter our adherence to PLOS ONE policies on sharing data and materials.