Pregnancy-Related Lumbopelvic Pain and its Relationship with Postural Control in Multigravid Pregnant Women

Abstract

Background and Aims: Pregnancy-related lumbopelvic pain (PLPP) affects 50-90% of pregnant women, substantially impairing their quality of life. The underlying mechanisms of PLPP remain largely unknown. Altered postural control has gained interest as a potential risk factor for PLPP. This study aims to determine the relationship between postural control and PLPP in the third trimester of pregnancy, while also exploring the differences in postural control between pregnant and non-pregnant women, and across different stages of pregnancy. Methods: A total of 68 women were included: 17 multigravid women in the first trimester of pregnancy (age 32.1±2.3yr, BMI 23.7±3.5), 25 multigravid women in the third trimester of pregnancy (age 32±2.6yr, BMI 28.4±4.2), and 26 non-pregnant women (age 29.7±3.7yr, BMI 22.2±1.8). Postural control was assessed in upright standing on a force plate under various postural conditions (with/without vision, feet together/20 cm apart, and/or stable/unstable support surface). Center of pressure (COP) variables were measured: mean COP sway anterior-posterior (AP), mean COP velocity AP, and COP 95% confidence ellipse area (CEA). In the third trimester, PLPP intensity was evaluated with the Numerical Pain Rating Scale (NPRS) to categorize into a no-PLPP subgroup (NPRS=0, N=9) and a PLPP subgroup (NPRS>0, N=16). Linear mixed models or Kruskal-Wallis tests, at nominal significance level 0.05, were used to compare COP variables between the no-PLPP and PLPP subgroups, between pregnant women (first or third trimester) and non-pregnant women, and between trimesters (uncorrected for BMI). Results: No significant differences in COP variables were found between the subgroups with and without PLPP (p>0.05). Pregnant women in the third trimester had significantly greater mean COP sway AP and COP 95% CEA compared to non-pregnant women when standing with feet together (p<0.05), though mean COP velocity AP did not differ significantly between these two groups (p>0.05). There were no significant differences in any COP variable between pregnant women in the first trimester and non-pregnant women, nor between trimesters (p>0.05). Conclusion: Pregnant women in the third trimester demonstrate larger postural sway compared to non-pregnant women, likely due to the biomechanical adaptations associated with advanced pregnancy. However, no direct relationship between these alterations in postural control and PLPP is identified.