RESUMEN
Low back pain is one of the most common complaints in pregnancy that interferes with work, daily activities and sleep. The aim of this study was to determine the effect of sitting pelvic tilt exercise on low back pain and sleep disorder during the third trimester in primigravidas. In this quasiexperimental study, 60 primigravidas who attended 3 prenatal clinics of Zanjan University of Medical Sciences, Zanjan, Iran, were selected by simple sampling, then they were randomly allocated into two groups, case and control. The case group did the sitting pelvic tilt exercise for 8 weeks during the third trimester. The control group just received usual prenatal care. Data collection was done by interview, using a Visual Analogue Scale [VAS] and a questionnaire which was carried out by the researcher on 0 and 56 days [pre and post intervention]. T- Test and Chi Square were used for data analysis. The intensity of low back pain in the case group after exercise was significantly decreased [P=0.0001], but in the control group, the intensity of low back pain increased as pregnancy advanced [P=0.0001]. Also in the case group, sitting pelvic tilt exercise reduced the sleep disorders in comparison with pre treatment and control group [P<0.05]. It seems that sitting pelvic tilt exercise is an imperative cure in pregnancy low back pain and sleep disorders that arise from it