Metabolic bone disease of prematurity (MBDP): refers to abnormalities in bone mineral content due to disorders of calcium and phosphorus metabolism in the body, resulting in reduced bone mass and abnormal bone structure. In the near term, ventilator dependence and fractures may occur, and in the long term, it may affect the height of the child and skeletal health in adulthood. Why the patient is preterm The main causes of MBDP are: 1. 80% of the minerals such as calcium, magnesium and phosphorus acquired by the fetus originate from the last 3 months of pregnancy, especially from 32 to 36 weeks of gestational age, and premature birth fails to complete the mineral reserve. 2, gestational age <32 weeks of prematurity, early birth gastrointestinal tract function is immature, most rely on intravenous nutrition, limiting the overall nutritional intake. 3, early birth is the period of the fastest growth rate in life, a large number of bone destruction and reconstruction requires more bone minerals, inadequate supplementation will appear osteoporosis. Lack of mechanical stimulation of the limbs. Premature babies use hormones and other special drugs, pregnant women receive magnesium therapy, etc. What are the signs and symptoms? MBDP usually appears 6 to 12 weeks after birth, but most of them lack typical clinical signs and symptoms. The signs may include: low weight and length gain, irritable crying, excessive sweating, head shaking, night terrors, occipital baldness, forehead elevation, skull softening, rib cartilage junction protruding like beads, fractures, etc. Persistent crying may be a sign of fracture. How to monitor? 1. Assessment of risk factors such as gestational age, birth weight, disease history, mother and child medication history, etc. 2. Growth and development level such as height, weight, bone shape, limb movement status, etc. 3. Detection of biochemical indicators such as blood and urine calcium and magnesium, bone alkaline phosphatase, vitamin D, etc. 4. Bone density measurement 5. Imaging examination Prevention and treatment countermeasures 1. Nutritional support Use formula designed for preterm infants, breast milk fortification; high mineral Supply generally continues until 3~4 months of corrective age; add extra calcium and phosphorus daily for exclusively breastfed preterm infants; maintain 25-hydroxyvitamin D at high levels. 2, mechanical stimulation Premature infants receive passive exercise after birth, moving limbs against passive resistance, through the mechanical pull on the bone and joints can promote bone mineralization; on the contrary, even with adequate nutritional supply, but the lack of moderate mechanical stimulation, bone development and remodeling will be affected, osteoclast activity is enhanced, bone resorption increases.