Obstructive sleep apnoea and its association with gestational hypertension

Hypertension develops in 10% of pregnancies. Snoring, a marker of obstructive sleep apnoea, is a newly identified risk factor for gestational hypertension. Moreover, obstructive sleep apnoea is an independent risk factor for incident hypertension in the non-pregnant population. The aim of the present study was to test the hypothesis that obstructive sleep apnoea is associated with new onset of hypertension among pregnant females. A case-control study was performed involving 17 pregnant females with gestational hypertension and 33 pregnant females without hypertension. Subjects were frequency-matched for gestational age and recruited in a tertiary obstetrical centre. Obstructive sleep apnoea was ascertained by polysomnography and defined by an apnoea/hypopnoea index (AHI) of >or=15 events x h(-1), without requirement for desaturation. The mean+/-sd AHI for normotensive pregnant females was 18.2+/-12.2 events x h(-1) compared with 38.6+/-36.7 events x h(-1) for females with hypertensive pregnancies. The crude odds ratio for the presence of obstructive sleep apnoea given the presence of gestational hypertension was 5.6. The odds ratio was 7.5 (95% confidence interval 3.5-16.2), based on a logistic regression model with adjustment for maternal age, gestational age, pre-pregnancy body mass index, prior pregnancies, and previous live births. In conclusion, gestational hypertension appears to be strongly associated with the presence of obstructive sleep apnoea.