Maternal physical activity levels in early pregnancy and the risk of spinal deformity among preschoolers at age 4: findings from the Shanghai birth cohort study

Xin Li^1,2Xuan Zhou^2,3Juping Liang²Zefan Huang²Mengdie Jin²Xiuhua Shen⁴Xuanfang Wang⁵Binbin Fu²Peijie Chen^1*Qing Du^2,3*

• ¹Shanghai University of Sport School of Exercise and Health, Shanghai, China
• ²Department of Rehabilitation, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
• ³Children's Rehabilitation Innovation and Transformation Research Center of Yuanshen Rehabilitation Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
• ⁴Department of Clinical Nutrition, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
• ⁵Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China

Objective: To study the impact of maternal physical activity levels before and after birth on the risk of spinal deformity in preschool children.A cohort study of 760 preschoolers and their mothers tracked maternal physical activity levels during the prenatal period and the two years postnatally, as well as for two years after the child's birth, using standardized questionnaires at 6, 12, and 24 months. The risk of spinal deformity was assessed by the angle of trunk rotation (ATR) at the thoracic (T5), thoracic-lumbar (T12), and lumbar (L4) segments of the spine, with max values noted. An adjusted logistic regression model was used to explore the relationships between prenatal and postnatal physical activity levels and the risk of spinal deformity in preschoolers.In 98 children (12.9%), ATRs were 3 or above, and 3 had ATRs of 5 at age 4. The duration of physical activity during early pregnancy (min/week) indicated a moderate risk of spinal deformity (with an ATR between 3 and 5) in children at age 4 (OR: 0.986, 95% CI: 0.976-1.001, P=0.084). Exercising outdoors <1 hour/day during 0-6 months reduced spinal deformity risk (3≤ATRs＜5) compared to >1 hour (OR=0.525, 95% CI 0.301-0.917, p=0.024). The risen risk of high ATR with long outdoor time was more significant when maternal blood calcium levels were low (OR=0.302, 95% CI 0.134-0.682; p=0.004).Long outdoor times (>1 hour/day) in infants under 6 months may be associated with changes in trunk rotation angle or postural stress. Exercise during early pregnancy may relate to good spine development in children. Further studies are needed on physical activity's role in scoliosis prevention.