Prevalence of back pain in pregnancy.

The prevalence of back pain was studied in 855 pregnant women who were followed from the 12th week of pregnancy, every 2nd week, until childbirth. The 9-month period prevalence was 49%, with a point prevalence of 22-28% from the 12th week until delivery. Because 22% of the women had back pain at the 12th week of the pregnancy, the 6-month incidence was 27%. Based on pain drawings, back pain was classified into three groups: In one group, pain was localized to the sacroiliac areas and increased as pregnancy progressed; in the other two groups, pain either decreased or did not change, respectively. True sciatica with a dermatomal distribution occurred in only 10 women (1%). Back problems before pregnancy increased the risk of back pain, as did young age, multiparity, and several physical and psychological work factors.