Sunday, June 22, 2014

High blood pressure, snoring, and sleep apnea during pregnancy

This article examines how high blood pressure and snoring during pregnancy can indicate sleep apnea in pregnant women.

Half of hypertensive pregnant women who snore and one quarter of those who do not snore have unrecognized obstructive sleep apnea (OSA), suggesting such women should be tested for this condition. Findings from this cohort study were published online May 29 in BJOG.
OSA is a sleep disorder associated with reduced nocturnal blood oxygen levels and other morbidity. The prevalence of OSA increases during pregnancy, affecting up to one third of women by the third trimester.
"We know that habitual snoring is linked with poor pregnancy outcomes for both mother and child, including increased risk of C-sections and smaller babies," lead author Louise O'Brien, PhD, associate professor, Sleep Disorders Center and Department of Neurology, University of Michigan, Ann Arbor, said in a news release. "Our findings show that a substantial proportion of hypertensive pregnant women have [OSA] and that habitual snoring may be one of the most telling signs to identify this risk early in order to improve health outcomes."
The study goal was to examine the prevalence of OSA among women with and without hypertensive disorders of pregnancy followed-up at obstetric clinics at an academic medical center. Pregnant women who were normotensive and those with hypertensive disorders (chronic hypertension, gestational hypertension, or preeclampsia) completed a questionnaire regarding habitual snoring. They also underwent overnight ambulatory polysomnography to determine the presence and severity of OSA.
Snoring and Hypertension Linked to OSA
Of 51 women with hypertensive disorders, 31 (61%) had OSA compared with 3 (19%) of 16 normotensive women (P = .008 by chi-square). Although nonsnoring women with hypertensive disorders generally had mild OSA, more than 25% of snoring women with hypertensive disorders had moderate to severe OSA.
Among women with hypertensive disorders, those who snored had a substantially greater apnea/hypopnea index than did nonsnorers (19.9 ± 34.1 vs 3.4 ± 3.1; P = .013), as well as a significantly lower oxyhemoglobin saturation nadir (86.4 ± 6.6 vs 90.2 ± 3.5; P = .021).
After stratification by obesity, the pooled relative risk for OSA in snoring versus nonsnoring women with hypertension was 2.0 (95% confidence interval, 1.4 - 2.8), or double the risk.
Women with chronic snoring were most likely to have chronic hypertension, whereas women with gestational hypertension were more likely to have the onset of snoring during pregnancy.
Limitations of this study include an inability to determine causality. In addition, only about one third of women who were invited to take participate actually did so.
"Hypertensive pregnant women who report snoring should be evaluated for [OSA,] since sleep apnea can be treated during pregnancy," Dr. O'Brien said. "Prompt recognition, evaluation, and management will not only improve health benefits for both moms and babies but may also help cut the high healthcare expenses of operative deliveries, taking care of babies who are admitted to the [neonatal intensive care unit] and other associated health risks."
In an accompanying commentary, F. Facco, MD, from the Department of Obstetrics and Gynecology, University of Pittsburgh, Pennsylvania, reviews current knowledge of sleep-disordered breathing (SDB) in pregnancy.
"[W]ell-designed clinical trials of CPAP use in pregnancy are needed to determine whether treatment of SDB during pregnancy can improve pregnancy outcomes; however, in the meantime we have to recognise that as our obstetrical patient population is becoming more obese, we will encounter more women with symptomatic SDB in pregnancy," Dr. Facco writes. "It is well documented that patients with symptomatic SDB, typically those who snore and report persistent complaints of significant sleep disruption and excessive daytime sleepiness, can benefit from CPAP in terms of sleep quality and daytime function. Therefore, in addition to encouraging women already prescribed CPAP to continue their therapy during pregnancy, obstetricians who suspect a patient may suffer from symptomatic SDB should refer her to a sleep specialist for diagnosis and possible treatment."
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