ABSTRACT
Aims: The precise changes in postures of each part of the spine of primigravid women are still ambiguous. This study aimed to find out the spinal curvature and pelvic tilt changes during the first pregnancy. Study Design: Observational longitudinal study (Cohort study). Place and Duration of Study: The study was conducted at a hospital clinic in Iran, between April 2014 and December 2014. Methodology: Thirty primigravid women at the first, second and third trimesters of pregnancy were recruited in this cohort study and their lumbar and thoracic curves changes and pelvic inclination angles were studied and compared with 18 age-BMI matched non-pregnant women. The curves were measured by use of a flexible ruler and the pelvic inclination angle was measured by a pelvic inclinometer device. Before starting the main study, the reliability and repeatability of the measuring tools were confirmed in this study (ICC>0.87). A one-way ANOVA and independent t-test were used for statistical analysis. Results: Marked increased curvature and inclination angles were revealed as pregnancy advanced (P<0.05). The lumbar lordosis significantly increased when the first trimester was compared with the second and third ones. The thoracic curvature showed significantly increased curvature between the first and third and between the second and third trimesters. None of the lumbar or thoracic curve showed significantly difference between the control group and pregnant women during the first trimester of pregnancy. Although ten weeks pregnancy increased lumbar lordosis and thoracic kyphosis (4.2%, 8%, respectively), but it was not significant when compared with no pregnant women. The pelvic inclination angle showed to be more sensitive than spinal curvatures as it showed significant increase within all trimesters and when compared to the control group. Interestingly, it increased nearly 2.5 times more at the end of pregnancy (236%). Conclusion: The present study showed a significant increase in most variables that became higher as the months of pregnancy increased. The results might help clinicians for prescribing suitable exercises or spinal orthoses during pregnancy. More research is recommended in this area in women intending to get pregnant.