Low back pain, ultrasonographic muscle thickness measurements and biopsychosocial factors at different trimesters of pregnancy

Background

Pregnancy-related low back pain is a multifactorial problem and its assosiation with pain intensity and biopsycosocial factors can not be fully explained. This study aimed to determine the psychosocial as well as biological/physical risk factors associated with self-reported low back pain (LBP) intensity during different trimesters of pregnancy.

Methods

This cross-sectional study comprised 107 pregnant women. An introductory information form for physical and medical characteristics, Visual Analog Scale (VAS) for low back pain intensity and Oswestry Disability Index (ODI) for degree of loss of functionality, Short Form-36 (SF-36) for quality of life and Pregnancy Physical Activity Questionnaire (PPAQ) for physical activity were applied. Abdominal muscle thicknesses and diastasis recti were measured by ultrasonography. Univariate regression was used to analyse associations between each plausible independent variable and low back pain intensity.

Results

Mean LBP intensity during 1st, 2nd ve 3rd trimesters were 26.8 $\pm$ 20.9, 27.3 $\pm$ 19.8, 21.6 $\pm$ 20.1 mm, respectively. ODI scores were associated with LBP intensity, explaining 11%, 13% and 26% of LBP severity during the 1st, 2nd ve 3rd trimesters, respectively. Other biological/physical variables like age, body mass index, muscle thickness and diastasis recti were not associated with pain intensity. SF-36 emotional role limitation (coef = −0.03, R2 = 0.20, p = 0.01) in the 3rd trimester and SF-36 pain score in the 1st (coef = −0.04, R2 = 0.12, p = 0.02) and 3rd (coef = −0.05, R2 = 0.26, p = 0.004) trimesters and PPAQ-sedentary was associated during the 2nd trimester (coef = 0.17, R2 = 0.17, p = 0.02) with pain intensity.

Conclusion

ODI scores were associated with LBP intensity in all three trimesters, with SF-36 pain domain in the 1st and 3rd trimesters, with SF-36 emotional role limitation only in the 3rd trimester and with sedentary activity level only in the 2nd trimester. İncreased pain intensity was surprisingly associated with a small number of biopsychosocial factors in all the trimesters. There is need for further large-sample studies.