Obstetrical analgesia in a parturient with antithrombin III deficiency.

Antithrombin III (AT III) deficiency is a rare inherited disorder which predisposes patients to thrombotic complications. Anticoagulation is necessary to prevent recurrent thrombosis and high doses of heparin are often required. Anticoagulation complicates analgesia in parturients with the condition. We describe such a patient, in pre-term labour, who was successfully managed during labour with intravenous nalbuphine and inhaled nitrous oxide (N2O).