Postural control and its Relation with Pregnancy-Related Lumbopelvic Pain in Multigravid Pregnant Women

Abstract

Background and Aims: Pregnancy induces biomechanical adaptations, challenging postural control. Pregnancy-related lumbopelvic pain (PLPP) affects 50%-90% of pregnant women, impairing their quality of life. The mechanisms underlying PLPP remain largely unknown, and its relationship with postural control is unclear. This study aims to determine potential differences in postural control between pregnant and non-pregnant women, as well as between different stages of pregnancy, and to investigate the relation with PLPP in the third trimester 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). The following variables were measured: mean center of pressure (COP) sway anterior-posterior (AP), mean COP velocity AP, and COP 95% confidence ellipse area (CEA). In the third trimester, PLPP intensity was assessed 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 across postural conditions between pregnant women (first or third trimester) and non-pregnant women, and between trimesters (uncorrected for BMI). The same tests were applied to compare COP variables between the no-PLPP and PLPP subgroups. Results: 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). In contrast, mean COP velocity AP did not differ significantly between these two groups (p>0.05). No significant differences were found for any COP variable between pregnant women in the first trimester and non-pregnant women nor between pregnant women in the first and third trimesters (p>0.05). Similarly, the COP variables did not differ significantly between subgroups with and without PLPP (p>0.05). Conclusion: Pregnancy in the third trimester affects postural control when standing with feet together, as shown by increased mean COP sway AP and COP 95% CEA. This is likely due to growing biomechanical adaptations associated with advanced pregnancy. Postural control seems unrelated to PLPP in the third trimester of pregnancy, although these findings should be interpreted cautiously due to the limited sample size. Our findings need confirmation in larger cohorts.