Pain pattern in pregnancy and "catching" of the leg in pregnant women with posterior pelvic pain.

STUDY
DESIGN: A cross-sectional study of symptoms and signs in pregnant women.
OBJECTIVES: To describe the clinical appearance of back pain in pregnancy and the relation between pain distribution and symptoms in women with posterior pelvic pain, in order to shed light on etiologic factors. SUMMARY OF BACKGROUND DATA: Back pain is common in the general population. During pregnancy, it is even more common, and back pain is experienced by about 50% of pregnant women. In the pregnant woman, differentiation between common low back pain and posterior pelvic pain is believed to be essential because these symptoms should be treated in different ways.
METHODS: The women were interviewed with a questionnaire. Those with back symptoms completed a pain drawing and were examined by an orthopedic surgeon. Based on the symptoms and findings, the women were divided into three groups: thoracic pain, lumbar pain, and posterior pelvic pain.
RESULTS: Of 335 pregnant women, 51% had back pain at the time of examination. The pain was more widespread compared with common low back pain. Seventy-one percent of the 171 patients examined by the orthopedic surgeon had a positive posterior pelvic pain test. These women more often had pain in the gluteal and posterior thigh regions. A "catching" feeling of the leg was described when walking by 44 of 122 these women, whereas only 1 of 49 women without a posterior pelvic pain test had such symptoms.
CONCLUSIONS: The higher prevalence of back pain in pregnancy may be due to several factors. In women with posterior pelvic pain, there is a specific symptom-a catching of the leg when walking. The most probable explanation for the catching is that local nociception disturbs muscular function in women with posterior pelvic pain because changes in the sacroiliac joint range of motion, which is very small, cannot cause this symptom.