Sleep-disordered breathing in hypertensive disorders of pregnancy: a BMI-matched study

Sleep-disordered breathing is more common in hypertensive disorders during pregnancy; however, most studies have not adequately accounted for the potential confounding impact of obesity. This study evaluated the frequency of sleep-disordered breathing in women with gestational hypertension and pre-eclampsia compared with body mass index- and gestation-matched normotensive pregnant women. Women diagnosed with gestational hypertension or pre-eclampsia underwent polysomnography shortly after diagnosis. Normotensive controls body mass index-matched within ±4 kg m^-2 underwent polysomnography within ±4 weeks of gestational age of their matched case. The mean body mass index and gestational age at polysomnography were successfully matched for 40 women with gestational hypertension/pre-eclampsia and 40 controls. The frequency of sleep-disordered breathing in the cases was 52.5% compared with 37.5% in the control group (P = 0.18), and the respiratory disturbance index overall did not differ (P = 0.20). However, more severe sleep-disordered breathing was more than twice as common in women with gestational hypertension or pre-eclampsia (35% versus 15%, P = 0.039). While more than half of women with a hypertensive disorder of pregnancy meet the clinical criteria for sleep-disordered breathing, it is also very common in normotensive women of similar body mass index. This underscores the importance of adjusting for obesity when exploring the relationship between sleep-disordered breathing and hypertension in pregnancy. More severe degrees of sleep-disordered breathing are significantly associated with gestational hypertension and pre-eclampsia, and sleep-disordered breathing may plausibly play a role in the pathophysiology of pregnancy hypertension in these women. This suggests that more severe sleep-disordered breathing is a potential therapeutic target for reducing the prevalence or severity of hypertensive disorders in pregnancy.