Stable motor and lung function throughout pregnancy in a patient with infantile spinal muscular atrophy type II

Patients with infantile spinal muscular atrophy rarely decide to have their own children especially if there is major respiratory impairment. We studied prospectively the pregnancy course and outcome of a 34-year-old woman with spinal muscular atrophy type II who delivered a healthy boy. Pregnancy was entirely uneventful, except that for 1-2 weeks after the caesarean section, the patient was extremely weak with dyspnoea and bulbar involvement. Several weeks after delivery her motor function had returned to pre-pregnancy levels. Pulmonary function remained stable throughout pregnancy, and thereafter, at approximately 70% predicted levels for forced vital capacity and for forced expiratory volume in 1 s. Blood gases after midgestation revealed low normal PaO(2) values around 85 mmHg and concomitant hyperventilation resulting in PaCO(2) levels below 30 mmHg.