Dynamic Imbalance of Lumbo-Pelvic Motion in Pregnant Women with Back and Pelvic Pain

ABSTRACT

OBJECTIVE: To investigate a biomechanism of pelvic pain in pregnancy by use of motion analyzer. METHOD: Ten pregnant women in the early third trimester and 10 healthy women as control were enrolled. A gait analysis by a Vicon 370 motion analyzer system was performed to investigate the dynamic lumbo-pelvic motion of pregnancy in biomechanical aspects. RESULTS: The mean maximal surface lordotic angle of pregnant women was 24.42+/-3.98 degrees, the mean minimal surface lordotic angle 20.64+/-4.27 degrees, and the mean maximal surface lordotic angle of controls was 21.61+/-2.43 degrees, the mean minimal surface lordotic angle 18.38+/-2.29 degrees (p>0.05). The mean maximal anterior pelvic tilt of pregnant women was 21.11+/-5.91 degrees, and the mean maximal anterior pelvic tilt of controls was 15.28+/-4.94 degrees (p<0.05). CONCLUSION: The angle of lumbar lordosis was within normal ranges but the anterior pelvic tilt was increased significantly in pregnancy. This can place mechanical stress on lumbo-pelvic region. This dynamic sagittal imbalance of the spine may be a considerable cause for low back and pelvic pain in pregnancy as indicated by the results of this study.