Obstructive Sleep Apnea (OSA) and NIH Women's Health Research

Signs, Symptoms, and Risk Factors

OSA is a sleep-related disorder that is characterized by episodes of partial or complete airway obstruction during sleep, resulting in reduced breathing or pauses in breathing.^{1 , 2} These breathing pauses can last seconds to minutes and may occur 30 or more times per hour throughout the night.³ Repeated pauses can cause complete cessation in breathing (apneas) or hypoxia and hypercapnia in the bloodstream.¹ OSA is commonly associated with loud, heavy snoring, although not all individuals with the condition snore and loud snoring is more common in men.^{2 - 4} Episodes typically follow a pattern of loud snoring, airflow cessation marked by silence, and abrupt resumption of breathing marked by loud gasping or snorting.^{1 - 3} As a result of disrupted sleep and repeated arousals, individuals with OSA may experience symptoms such as excessive daytime sleepiness, nonrestorative sleep, impaired attention and memory, sexual dysfunction, dry mouth, and mood disturbances.^{1 , 2 , 4} OSA is also associated with increased risk of comorbid conditions, including hypertension, cardiovascular disease, stroke, impaired glucose regulation, depression, and frequent headaches.^{1 , 2}

The risk factors for OSA include physiological and anatomical factors. Physiological factors that might contribute to OSA include obesity; endocrine disorders; male sex; older age; and lifestyle behaviors, such as drinking alcohol and smoking.^{1 , 2 , 5} Craniofacial or anatomical features, such as a recessed mandible, increased neck circumference, enlarged tonsils or adenoids, a large tongue, or small airways, can increase susceptibility to OSA by compromising airflow.^{1 , 2 , 5} Sleep position also influences risk, with back sleeping increasing the likelihood of airway obstruction in some individuals.² Genetic factors also contribute to the risk of developing OSA.^{1 , 5}

Impact on Women's Health

Hormonal changes may increase women's risk for OSA. These changes can occur during pregnancy, throughout perimenopause or postmenopause, and among women with polycystic ovary syndrome.⁶ OSA during pregnancy is associated with increased risk of pregnancy and birth complications, including gestational diabetes, high blood pressure, cesarean delivery, preterm birth, and low birthweight.⁶ Women also may experience sleep apnea symptoms differently than men. Rather than presenting with the hallmark symptom of loud snoring, women more commonly report insomnia; excessive daytime sleepiness; fatigue; frequent nighttime awakenings; anxiety and depression; and headaches, particularly in the morning.⁶ OSA may be more difficult for health care providers to recognize in women during or after menopause, as OSA symptoms such as sleep disruption, fatigue, night sweats, cognitive symptoms, dry mouth, and headaches overlap with menopausal changes.⁶

Diagnosis and Treatment

Most individuals with OSA are unaware that their breathing repeatedly stops and restarts during sleep.² When OSA is suspected, a health care provider typically reviews a patient's medical and family history and performs a physical exam, with attention to the mouth, neck, and throat.^{2 , 7} A diagnostic study, done either in a sleep laboratory or via a home sleep apnea test, is used to confirm the diagnosis and assess severity. Depending on the individual's symptoms, additional tests may be ordered to rule out other sleep disorders; gather more information on sleep patterns; or identify contributing conditions, such as hormone imbalances.^{2 , 7}

Treatment approaches vary depending on the severity of OSA and individual patient factors. Positive airway pressure (PAP) therapy is a common first-line treatment for OSA, and oral appliance therapy may be used in selected patients.^{8 , 9} Lifestyle modifications—such as physical activity, weight loss, side sleeping (positional therapy), and limiting alcohol or caffeine—may help reduce the severity of symptoms and are often used in conjunction with other treatments.^{8 , 9} Tirzepatide, a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) agonist, has been approved by the Food and Drug Administration (FDA) for the treatment of moderate to severe OSA in adults with obesity.¹⁰ Sometimes providers may also recommend orofacial therapy to help strengthen and reposition the tongue and muscles involved in upper airway functions.⁸ In some cases, surgical interventions may be considered, including upper or lower jaw advancement, weight-loss surgery, tonsillectomy, removal of obstructive airway or mouth tissue, or hypoglossal nerve stimulation device implantation.⁸

Ongoing Research

Interest is growing in understanding how menopause influences the risk, presentation, and progression of OSA in women. Areas of ongoing study include the roles that hormonal changes, visceral fat accumulation, and sex-specific patterns of symptoms and sleep-disordered breathing may play in OSA diagnosis and management in women.^{11 , 12}

More broadly, researchers continue to investigate new treatment approaches and diagnostic tools for OSA. Following the FDA approval of tirzepatide for the treatment of moderate to severe OSA in adults with obesity, researchers continue to explore additional pharmacotherapies for the treatment of OSA.¹⁰ Researchers are also investigating the use of wearable devices and remote-monitoring technologies to improve OSA screening and diagnosis.⁹ This includes examining whether data from sensors that track breathing, snoring, movement, heart rate, and oxygen levels can be combined with machine-learning approaches to enable more accurate, personalized, and accessible home-based assessment and management of OSA.⁹

The primary NIH organization for research on OSA is the National Heart, Lung, and Blood Institute (NHLBI). NHLBI's National Center on Sleep Disorders Research (NCDSR) supports and coordinates federal research, training, and education efforts to advance understanding of sleep disorders, circadian rhythm biology, and sleep health. NHLBI's current sleep apnea research focuses on improving the diagnosis of sleep apnea and treatment adherence, developing new therapies and devices, and understanding how sleep apnea contributes to cardiovascular, metabolic, neurologic, and women's health outcomes across the lifespan.

NHLBI has funded several studies that have evaluated sleep apnea in women. In partnership with the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b) found that sleep deficiency and mild sleep apnea during pregnancy increase the risks of pre-eclampsia and diabetes. Using data from nuMoM2b, another study found that sleep apnea during pregnancy also raises the risks for high blood pressure and metabolic syndrome in the mother for years after giving birth. The Institutes are now conducting a Phase III Maternal-Fetal Medicine Units (MFMU) Network trial to test whether treating sleep apnea can reduce the rate of hypertensive disorders of pregnancy.