Pregnancy-associated osteoporosis is rare and self--limiting. We report two clinical cases, with beginning of back pain during a 1st pregnancy. In the 1st case, the pain became severe after a fall, and she had other risk factors of fracture, like low calcium intake, and a treatment with thyroid hormones for weight loss. In the 2nd case, we did not find any. Both were diagnosed of osteoporosis by bone densitometry and radiology (multiple vertebral compression fractures). They had a favorable progression with life-style measures, calcium and vitamin D supplementation, and oral biphosphonate in the 2nd case. Nevertheless, both still suffer the impact.