Sleep-disordered breathing (SDB) is characterized by a range of abnormalities from snoring with subtle airflow narrowing to complete airway obstruction (apneas).1,2 These perturbations result in disrupted sleep and intermittent hypoxia, which have been subsequently shown to increase sympathetic activity and oxidative stress and have been associated with cardiovascular disease and hypertension.3, 4, 5, 6AJOG at a Glance
Sleep-disordered breathing (SDB) in pregnancy is associated with increased preeclampsia risk.
Arterial stiffness, a marker of vascular health, is increased in women who develop preeclampsia.
It is unknown if SDB in pregnancy is associated with elevated arterial stiffness.
SDB was independently associated with increased arterial stiffness throughout gestation.
Excessive daytime sleepiness was associated with increased arterial stiffness in women with SDB in the first or the second trimester (termed midgestation).
Midgestation SDB combined with excessive daytime sleepiness was associated with a 5.7 odds ratio for preeclampsia.
SDB in the third trimester (termed late-gestation) was associated with an 8.2 odds ratio for preeclampsia.
This study demonstrated an independent association between maternal SDB and arterial stiffness throughout pregnancy and established the role of excessive daytime sleepiness as an effect modifier of arterial stiffness and preeclampsia risk.
The physical and hormonal changes of pregnancy (ie, weight gain, reduced upper airway size, estrogen-related rhinitis) may predispose women to SDB, and accumulating evidence links SDB to adverse pregnancy outcomes.7,8 Snoring is a hallmark feature of SDB, and is more prevalent in pregnancy, particularly in the third trimester (35%), compared with nonpregnant women of similar age (4%–14%).9 Importantly, maternal snoring has been associated with adverse pregnancy outcomes, including fetal growth restriction, gestational hypertension, and diabetes.10,11 Polysomnography (overnight sleep recordings) is the reference standard for diagnosing SDB, and allows the measurement of complete (apneas) and partial (hypopneas) upper airway obstructions during sleep. However, polysomnography is not always feasible because it requires participants to sleep overnight in the laboratory, and is associated with greater cost and resource requirements. In previous studies using polysomnography in pregnancy, the prevalence of SDB (17%–45%) was similar to that obtained from snoring-based assessments.1 Importantly, SDB in pregnancy is most often characterized by snoring and associated subtle flow limitation rather than by apneas.12, 13, 14, 15
Women with SDB (defined either by snoring or polysomnography) were found to have a 2.3-fold greater odds for developing a hypertensive disorder of pregnancy, that is, gestational hypertension or preeclampsia, independent of major confounders, including obesity.8 Increased sympathetic activity, systemic inflammation, and oxidative stress may be the mediating mechanisms in the association between SDB and elevations in blood pressure.16, 17, 18 Similarly, a large prospective pregnancy cohort study using sleep assessments to diagnose SDB found an independent association between SDB and preeclampsia (odds ratio [OR], 1.95; 95% confidence interval [CI], 1.18–3.23) and hypertensive disorders of pregnancy (OR, 1.73; 95% CI, 1.19–2.52).7 However, studies examining mechanisms linking SDB with adverse outcomes and vascular health in pregnancy are lacking.
SDB is an independent risk factor for cardiovascular disease, and has been associated with increased arterial stiffness in the general population.19,20 Arterial stiffness is a composite indicator of vascular health and an independent predictor of cardiovascular morbidity and mortality.21 Arterial stiffness and hemodynamic parameters represent early noninvasive indicators of subclinical vascular dysfunction.21 Consequently, their early measurement and detection may enable timely intervention to improve vascular outcomes not only in the short term, but also in the long term, given that the history of preeclampsia is associated with increased cardiovascular risk later in life.22, 23, 24 Because vascular dysfunction is a central feature of pathologic processes preceding preeclampsia, arterial stiffness also represents a promising biomarker in pregnant women. Indeed, we have previously demonstrated that carotid-femoral pulse wave velocity (cfPWV), the reference standard for the measure of arterial stiffness, is predictive of preeclampsia,25 whereas we also found that cfPWV values measured throughout pregnancy diverged after 14 to 17 weeks’ gestation, which is known to be the most critical period for preeclampsia prophylaxis26; increasing arterial stiffness was noted among women who subsequently developed preeclampsia.27 However, it is unknown if SDB contributes to increased arterial stiffness in this population. Therefore, the aims of the present study were to: (1) characterize arterial stiffness and hemodynamic parameters in women, with and without SDB throughout gestation, and (2) investigate the association of SDB and sleep quality with preeclampsia.