# Management of X-Linked Hypophosphatemia During Pregnancy: Case Report and Literature Review

## TL;DR

This case report describes the successful management of X-linked hypophosphatemia during pregnancy using phosphate and calcitriol, with no maternal or fetal complications.

## Contribution

The paper provides a real-world example of managing XLH during pregnancy in the absence of safety data for burosumab and offers guidance for clinicians.

## Key findings

- Discontinuation of burosumab and treatment with phosphate and calcitriol maintained safe phosphate levels during pregnancy.
- Monthly biochemical monitoring ensured no maternal or fetal complications.
- The patient delivered a healthy newborn after a full-term pregnancy.

## 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.

The management of X-linked hypophosphatemia (XLH) during pregnancy poses significant clinical challenges due to physiological changes in mineral metabolism and the absence of evidence-based guidelines. This case report describes a successful pregnancy in a woman with XLH treated with conventional phosphate and calcitriol supplementation, closely monitored throughout gestation. Maternal and neonatal outcomes were favourable, with no reported complications. By combining clinical experience with a targeted literature review, this report helps fill a critical knowledge gap and offers clinicians a concrete example of how to safely manage hypophosphatemia during pregnancy, supporting maternal skeletal health and optimal fetal development.