I read with interest the case report by von Guionneau and Stone detailing management of a pregnant woman with limb-girdle muscular dystrophy type 2i (LGMD2i). 1 Although monitoring of respiratory function in the second half of pregnancy in these women is mentioned in this case report, it is not given the emphasis that it warrants, given the frequency at which diaphragmatic weakness and sleep apnoea occur in this disorder. 2-5 The latter is not specific to LGMD2i, indeed sleep-disordered breathing is seen not uncommonly in individuals with myotonic dystrophy, Duchenne muscular dystrophy, Becker muscle dystrophy and fascioscapulohumeral dystrophy. Assessment of these women to ensure early detection of abnormalities, particularly of nocturnal respiratory failure, is therefore crucial. The authors mention lung function tests, but I think it is important to highlight that these should be performed supine as well as sitting. Two studies demonstrated a significant reduction in FVC in 12 of 32 (38%) non-pregnant women with LGMD2i in the supine position compared with sitting. 3,6 Non-invasive ventilation is a key treatment for those individuals with respiratory failure as a result of this condition. In a combined group of 27 patients with congenital muscular dystrophy and LGMD2i, 14 individuals (52%) had either nocturnal or diurnal hypercapneic respiratory failure. 7 Importantly, a normal arterial blood gas analysis during the day does not exclude this diagnosis, as 10 patients with normal daytime PaCO 2 had nocturnal hypercapneic respiratory failure. Transcutaneous CO 2 capnography/polysomnography can be performed if hypoventilation is suspected. Elevated serum bicarbonate is suggestive of nocturnal hypercapnia. An additional consideration at delivery is to ensure these women are closely observed while receiving magnesium sulphate, as this has been reported to result in respiratory compromise in neuromuscular disorders. 8 Continuous transcutaneous PCO 2 and PO 2 monitoring is not yet available in all centres, but this is likely to be increasingly used in the future during labour and delivery to monitor these women.