Erector spinae plane block for obstetric analgesia in a patient with factor XI deficiency: a case report.

Factor XI (FXI) deficiency is a rare bleeding disorder characterized by a quantitative or qualitative deficiency of FXI. The symptoms are highly variable, and the severity and site of bleeding is unpredictable and does not necessarily correlate with FXI levels. FXI deficiency is classified by phenotype: bleeding or non-bleeding, depending on the clinical manifestations. We present the case of a woman in her twenties diagnosed with FXI with a bleeding phenotype. The patient requested labour analgesia, but the haematology department contraindicated neuraxial techniques, given her history. An ultrasound-guided lumbar erector spinae plane (ESP) block was performed, achieving pain relief after 45 min. ESP block could be an alternative to consider when neuraxial analgesia is contraindicated in labour.