Abstract
Hypophosphatemia during pregnancy poses unique clinical challenges due to physiological changes in mineral metabolism, with potential impacts on maternal and fetal health, but limited evidence to guide treatment. We describe the case of a woman with X-linked hypophosphatemia, previously treated with burosumab for lower limb pseudofractures. Due to her desire for pregnancy and the absence of safety data on burosumab during gestation, the drug was discontinued and treatment with phosphate supplements and calcitriol was initiated. Following assisted reproduction with preimplantation genetic diagnosis, the patient successfully carried the pregnancy to term and delivered a healthy newborn. Monthly biochemical monitoring allowed for safe adjustment of therapy, maintaining serum phosphate levels within or near the normal range without maternal or fetal complications. We also review the available literature on hypophosphatemia in pregnancy, emphasizing the need for individualized management and close monitoring.