The association of back pain with physical inactivity and hypothyroidism in pregnant women.

Background: During pregnancy, structural and functional changes usually occur in the body, which has various consequences, including lower back pain (LBP) and hypothyroidism. One of the risk factors for these problems is physical inactivity.

Objective: This study aimed to investigate the association of back pain and physical inactivity, weight gain, and hypothyroidism in pregnant women.

Methods: In this cohort study, 420 pregnant women (26.333 ± 5.820 years old) were included. At first, participants answered this question: "Do you have any plans for pregnancy in the next month?" If the answer was yes, further evaluations were performed. The physical activity and pain intensity were measured by the International Physical Activity Questionnaire Short Form (IPAQ-S) and Visual Analogue Scale. Serum TSH was measured by automated chemiluminescence and commercial kits. Measurements were conducted before, the first, second, and third trimester of pregnancy.

Results: Women reporting LBP were less engaged in physical activities and weight gained in the second and third trimesters of pregnancy was significantly higher than pregnant women without LBP (p< 0.05). TSH level and weight gained in pregnant women with low physical activity level was significantly higher than pregnant women with moderate and high physical activity (p< 0.05) (without significant difference in TSH and BMI). The physical inactivity (before: OR: 1.11 95% CI: 0.89 to 1.22; first trimester: OR: 1.09 95% CI: 1.02 to 1.59; second trimester: OR: 0.92 95% CI: 0.87 to 1.31; third trimester: OR: 1.12 95% CI: 1.02 to 1.39), TSH (OR: 0.85 95% CI: 0.57 to 1.29), and weight gain (second trimester: OR: 0.87 95% CI: 0.92 to 1.59; third trimester: OR: 1.44 95% CI: 1.02 to 1.98; p< 0.05) did predict increased pain intensity.

Conclusion: Using health-oriented approaches to increase physical activity and normalize thyroid function and weight gain during pregnancy can have beneficial effects on LBP.