Risk factors for sleep-disordered breathing in pregnancy

The stimulating paper of Pien et al 1 reported the findings of a prospective cohort study of pregnant women examining risk factors for sleep-disordered breathing (SDB). It was notable that, despite a marked increase in the number of women with obstructive sleep apnoea (OSA) from the first to third trimester (from 10.5% to 26.7%, respectively), there were no significant associations between any SDB variable and development of gestational hypertension or preeclampsia or with preterm delivery, gestational diabetes or low birth weight. The authors acknowledged that, in their study, determination of any associations between OSA and such secondary measures was limited due to low statistical power, relatively low numbers of participants with moderate or severe OSA or with gestational diabetes, and a lack of manifestation of OSA until the third trimester, the last of which might be relevant given the potential importance of pre-existing OSA compared with incident gestational OSA.2