Abstract
BACKGROUND Pregnancy and lactation-associated osteoporosis (PLO) is a rare condition characterized by fragility fractures occurring during late pregnancy or lactation. It is associated with pregnancy- and lactation-related bone metabolic disorders and risk factors such as low body mass index (BMI). Given the absence of standardized guidelines and limited clinical awareness, PLO is often misdiagnosed or diagnosed late. The patient described in this report experienced both delayed treatment and misdiagnosis. The findings suggest that bisphosphonates have limited efficacy in improving bone mineral density (BMD) among patients with low BMI. CASE REPORT A 31-year-old Chinese woman with low BMI developed low back pain 2 weeks after her first childbirth. Initial physical therapy aggravated her symptoms. Magnetic resonance imaging revealed multiple vertebral fractures, and BMD testing confirmed severe osteoporosis. Laboratory tests showed vitamin D deficiency and normal calcium levels. Calcium and vitamin D (CaD) supplementation failed to relieve symptoms. After consultation with a spine surgeon and additional evaluations, she was diagnosed with PLO. Breastfeeding was discontinued; bisphosphonate therapy, thoraco-lumbo-sacral-orthotic bracing, and continued CaD supplementation were initiated. Pain gradually improved, but no clinically significant increase in BMD was observed at the 19-month follow-up. CONCLUSIONS PLO remains underrecognized in clinical practice. In the diagnosis and management of PLO, low BMI should be considered an important risk factor. The treatments described in this report - including breastfeeding cessation, CaD supplementation, orthopedic bracing, and administration of anti-osteoporotic medication - may serve as a reference for managing similar cases. Multicenter studies are needed to establish diagnostic and treatment guidelines for PLO.