From the Journals

Sleep-disordered breathing promotes elevated arterial stiffness and preeclampsia



Sleep-disordered breathing was significantly associated with increased odds of preeclampsia and with greater arterial stiffness in high-risk pregnancies, based on data from 181 individuals.

The intermittent hypoxia resulting from sleep-disordered breathing (SDB) has been linked to cardiovascular disease and hypertension, wrote Kim Phan, PhD, of McGill University, Montreal, and colleagues.

SDB has been associated with increased preeclampsia risk, and women with preeclampsia show increased arterial stiffness, but an association between SDB and arterial stiffness in pregnancy has not been explored, they said.

In a study published in the American Journal of Obstetrics & Gynecology, the researchers reviewed data from 181 women with high-risk singleton pregnancies recruited from two tertiary obstetrics clinics in Montreal. High-risk pregnancy was defined as meeting at least one of the following criteria: age 35 years and older, body mass index 25 kg/m2 or higher, chronic hypertension, preexisting diabetes mellitus, preexisting renal disease, or personal or first-degree relative with a history of preeclampsia.

Participants were assessed at each trimester via the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Restless Legs Syndrome questionnaire. Sleep-disordered breathing was defined as loud snoring or witnessed sleep apneas at least three times a week. Arterial stiffness was assessed via applanation tonometry every 4 weeks from baseline throughout pregnancy.

Overall, 23% of the study population met the criteria for SDB; SDB in the first or second trimester was associated with a significantly increased risk of preeclampsia (odds ratio 3.4). The effect of SDB on preeclampsia was increased in women who reported excessive daytime sleepiness, defined as scores higher than 10 on the Epworth Sleepiness Scale. The odds ratio for preeclampsia in the first or second trimester increased to 5.7 in women with hypersomnolence in addition to SDB. The risk of preeclampsia was even higher (OR 8.2) in the third trimester.

Self-reported total sleep time decreased in the second and third trimesters compared with the first, but reports of excessive daytime sleepiness remained consistent throughout the pregnancies, the researchers noted.

The results highlight the need to screen pregnant women for SDB in all three trimesters; however, “future studies will need to assess the incremental benefit of integrating SDB into risk assessment calculators in pregnancy,” the researchers wrote in their discussion. Randomized trials are needed to determine the value of interventions such as continuous positive airway pressure to reduce arterial stiffness and the risks of hypertensive disorders of pregnancy, they said. More data also are needed to examine the role of excessive daytime sleepiness as a modifier of arterial stiffness and preeclampsia risk, they noted.

The findings were limited by the prospective design, which prevents conclusions of causality, the researchers noted. Other limitations included the focus on high-risk pregnancy, which may limit generalizability, and the use of symptoms, not sleep recordings, to identify SDB, they said.

However, the results show an independent association between SDB and arterial stiffness during pregnancy, and offer potentially useful insights into the mechanisms of SDB-associated cardiovascular conditions, they noted.

“This work may inform future studies exploring the value of using arterial stiffness, as an early noninvasive indicator of subclinical vascular dysfunction in pregnant women with SDB,” they concluded.

The study was supported by the Fonds de recherche du Quebec – Sante (FRQS), Heart and Stroke Foundation of Canada, McGill University’s academic enrichment fund, and the Canadian Foundation for Women’s Health. The researchers had no financial conflicts to disclose.

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