Objectives: To explore if joint mobility, as a measure of connective tissue quality, could be a predictor for pregnancy-related low back pain after pregnancy and to evaluate local corticosteroid injection treatment in women with persistent pelvic girdle pain long after childbirth. Material and methods: To investigate joint mobility in relation to pain, 200 women were examined repeatedly from early pregnancy until three months after delivery. Their mobility in left fourth finger abduction in early pregnancy was compared with clinically assessed low back and pelvic pain 3 months after delivery. To evaluate local corticosteroid injection treatment, 36 women with persistent PGP were included in a randomised controlled trial (RCT) and randomised to either corticosteroid injection or saline injection on one occasion at the ischial spine bilaterally, with a follow-up after four weeks. In both studies, the women were asked about obstetric history, to complete a pain drawing, estimate their level of pain on a visual analogue scale (0-100) and estimate how they manage their everyday activities on a questionnaire, Disability Rating Index (DRI). In the RCT, the 36 women also completed Short Form 36 (SF-36), a quality of life questionnaire, six-minute walk test (6MWT), and isometric trunk flexion and extension were examined. Results: Women with low back and pelvic pain three months after pregnancy had increased finger laxity in early pregnancy. The larger the finger angle and the more pregnancies, the greater the risk of low back and pelvic pain after pregnancy. In the RCT, at follow-up, the women who received corticosteroid injection treatment improved in walking ability, estimated physical ability and isometric trunk extension more than those who received saline injections. Conclusions: Increased joint mobility, as measured by finger joint mobility, together with the number of previous pregnancies, may be an indicator of low back and pelvic pain postpartum. One single corticosteroid injection treatment to intra-pelvic structures improved function in women with persistent PGP which may indicate a source of pain.