Infants born <32 weeks or <1500 g are at risk of developing metabolic bone disease of prematurity (MBDP). Additional risk factors increase the need for regular screening.

Most babies with MBDP are calcium deficient. Parathyroid hormone (PTH) should be used to guide initial treatment and treatment response.

Calcium deficiency may occur even with normal serum calcium levels.

Phosphate deficiency may also occur and be co-existent with calcium deficiency. This is caused by the action of an elevated PTH and vitamin D deficiency.

Vitamin D deficiency can co-exist with calcium deficiency and concentration should be maintained >50 nmol/L.

Metabolic bone disease of prematurity (MBDP) is a significant cause of morbidity within the neonatal population. However, there is uncertainty about which babies need screening and at what thresholds treatment is warranted, and the consensus approach to management has shifted in recent years. This has led to confusion surrounding timing of investigations, result interpretation and the optimum way to administer prescribed supplementations. Due to the lack of clear cut-offs and thresholds for investigation and management within current literature, a consensus approach at best can be recommended, with an aim to be practical and deliverable across the full range of neonatal services.

MBDP affects 55% of infants <1000 g and 23% of those <1500 g, with increasing prevalence in those with additional risk factors such as diuretic or steroid use.1 During the final trimester of pregnancy, the placenta delivers significant concentrations of phosphate and calcium, and infants born prior to this are most at risk of developing deficiencies. Delivering comparative concentrations of electrolytes either enterally or within parenteral nutrition (PN) is challenging.2 MBDP is often diagnosed with radiographic changes between weeks 8 and 12 postnatally, though a reduction in bone density of 20–40% is required before this is apparent. Biochemical markers can …