eMedicine Specialties > Neurology > Sleep-Related Diseases

Sleep Dysfunction in Women

Author: Gila Hertz, PhD, ABSM, Director, Center for Insomnia and Sleep Disorders, Clinical Associate Professor of Psychiatry and Behavioral Sciences, State University of New York at Stony Brook
Coauthor(s): Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Contributor Information and Disclosures

Updated: Dec 15, 2008

Introduction

Background

Women are twice as likely as men to have difficulties falling asleep or maintaining sleep, although before puberty no significant differences are apparent. Hormonal factors, psychological issues, most particularly depression as well as pain syndromes, are common concerns when addressing insomnia in women. Poor sleep quality and inadequate sleep affect many of the measures of quality of life.

Restless legs syndrome (RLS) is more prevalent in women and occurs at higher rates during pregnancy.

Definitions and terminology

• Insomnia - Difficulty with falling asleep or staying asleep
• Sleep-onset insomnia - Difficulty with falling asleep
• Sleep-maintenance insomnia - Fragmented sleep, difficulty with maintaining sleep
• Circadian rhythm - Approximately 24-hour cycles that are generated endogenously by an organism
• Sleep-disordered breathing (SDB) - Some degree of sleep-related upper airway obstruction, ranging in severity from upper airway resistance syndrome (UARS) to obstructive sleep apnea (OSA)
• Restless legs syndrome - Characterized by the urge to move legs or other limbs during periods of rest or inactivity

Pathophysiology

In general, sex steroids play a role in the etiology of sleep disorders in women, either by having a direct effect on sleep processes or through their effect on mood and emotional state. Sex steroids influence EEG sleep during the luteal phase by increasing the EEG frequency and core body temperature. Lack of estrogen later in life contributes to vasomotor symptoms, including hot flashes that cause sleep disturbances and insomnia. Decreased estrogen also plays a role in the etiology of sleep apnea.
 
In addition to hormonal factors, psychiatric conditions, particularly mood disorders, as well as chronic pain conditions are closely associated with insomnia.

Pathophysiologic factors in some of the major sleep disorders seen in women are as follows:

Sleep-disordered breathing: This involves various degrees of pharyngeal obstruction ranging from UARS to OSA. Obstruction results from high negative pressure generated by the inspiratory effort and failure of the dilating upper airway muscles to maintain airway patency. Contributing factors are degree of muscle atonia and various anatomical abnormalities that increase airway occlusion (eg, enlarged tonsils, macroglossia). Obesity is a known risk factor for OSA. Women with OSA are likely to be more obese than men, though fat distribution is different. The prevalence, nature, and severity of OSA in women changes with menopause.
 
Postmenopausal women have twice the rate of OSA as compared to premenopause. Women demonstrate more partial obstructive events (hypopneas) than complete OSAs. In addition, the duration of hypopneas, when present, tends to be shorter in women than in men. OSA is mostly evident during REM sleep. Regardless of age, OSA is less severe in women than in men. A possible explanation is the effect of a female hormone (probably progesterone) on the activity of the dilator muscle of the pharynx. In a study performed in healthy women with regular menstrual cycles, upper airway resistance was found to be lower during the luteal phase of the menstrual cycle than the follicular phase. Progesterone levels are elevated during the luteal phase.

Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD): These are idiopathic disorders that can cause profound disruption. RLS, a waking disorder that usually occurs before sleep onset, is associated with discomfort in the calves causing restlessness in the legs, which is relieved by movement. Iron deficiency has been implicated in the pathophysiology of RLS. The possibility of a genetic basis has been suggested for primary RLS. PLMD, occurring during sleep, involves isolated periodic movements of the lower limbs, usually followed by arousal from sleep. In severe cases, frequent leg movements can cause significant sleep interruption, resulting in complaints of insomnia or excessive sleepiness.

Narcolepsy: The 4 major features of narcolepsy are (1) daytime sleepiness, (2) hypnagogic hallucinations, (3) cataplexy, and (4) sleep paralysis. These features are related closely to features normally occurring exclusively during rapid eye movement (REM) sleep. The symptom of cataplexy, for example, which involves sudden loss of muscle tone during waking hours, is identical to muscle paralysis normally experienced during REM sleep. Thus, narcolepsy has been hypothesized to represent a dissociative process of REM sleep mechanisms and an intrusion of these mechanisms into waking hours.

Circadian rhythm disorders: The most common circadian sleep disorder is delayed sleep phase syndrome (DSPS), with typical onset at puberty. DSPS is characterized by a significant delay (3-4 h) in both bedtime and wake time in the presence of a normal overall total sleep time. DSPS may also relate to an eveningness chronotype, an individual preference for increased activity at night. A Spanish study, investigating chronotypes in students aged 18-30 years, has shown a greater preference toward eveningness in men. Thus, gender differences are possibly the result of sex influences on the regulation of the biological clock.

Frequency

United States

The difficulty most frequently reported by women is insomnia. Insomnia rates during puberty have been described in girls but not boys. Women are at 41% greater risk for developing insomnia as compared with men and this risk increases with age. By age 65 years the insomnia risk is approximately 73% greater for women. In addition, insomnia is a significant comorbidity in many disorders. The most common disorders associated with insomnia are psychiatric illnesses. Major depression and dysthymia are most closely associated with insomnia. Numerous studies have also shown a close association of chronic pain syndromes with insomnia.

The prevalence of pathological SDB has been estimated at 5.2% for women aged 40-64. Over 30% of elderly persons demonstrate at least mild sleep-related breathing abnormalities, as defined by an apnea/hypopnea index of 5 or greater. Postmenopausal women are 2.6 times more likely than premenopausal women to have an apnea-hypopnea index (AHI) greater than 5.

The incidence and prevalence of SDB during pregnancy is unknown. Generally, sleep studies have found no evidence of significant SDB during pregnancy, possibly reflecting increased circulating levels of progesterone.

The prevalence of PLMD increases significantly with age. Studies have estimated that as many as 45% of the independently living population older than 65 years show the minimal criteria for diagnosis of PLMD.

The prevalence of RLS has been reported at 10% for those aged 30-79 years. Higher rates of RLS have been reported in women as compared with men and Europeans as compared with Asians. Reported rates among Caucasians and African Americans are similar. Smoking, diabetes mellitus, pregnancy, increasing age, and greater body mass index significantly increase the incidence of RLS. Iron deficiency anemia has also been associated with RLS.

International

Estimated prevalence of SDB in a study from Iceland has been reported at 2.5% for women aged 40-59.

Mortality/Morbidity

Studies have shown that sleep problems are linked to more physical and emotional disturbances in women than in men. Among women, those with worse sleep showed more emotional distress and depression. They also had higher body mass index (BMI), more inflammation, and less sensitivity to insulin. Specifically, the most common comorbidities with sleep disorders are as follows:

• Snoring, often a sign of partial airway obstruction, has been shown to be associated with high blood pressure and increased risk for OSA. Snoring increases during pregnancy, particularly during the last trimester. About 14% of women who report habitual snoring during pregnancy had pregnancy-induced hypertension. In addition, snoring may be responsible for nighttime increases in blood pressure in preeclampsia. Finally, infants born to mothers who were habitual snorers more frequently had low birth weights.
• Snoring is also a risk factor in the development of OSA in postmenopausal women. Other contributing factors are weight and neck size. In addition to sleep disturbances and daytime sleepiness, OSA can lead to cardiovascular complications.
• OSA has been associated with hypertension and more recently with insulin resistance and metabolic disease.
• Older women who sleep more than 9 hours of sleep are at higher risk for ischemic stroke.
• Psychiatric conditions, particularly depression and anxiety disorders, are the most common comorbidities with insomnia.
• RLS may be secondary to medical conditions that have iron deficiency, including iron deficiency anemia, renal disease, and pregnancy.

Race

The prevalence of obesity is higher in black women than in white women. Obesity places women at higher risk of developing OSA, particularly after menopause. Sleep apnea is pervasive in non-European–American women. Compared with European–American women, non-European–American women have more blood oxygen desaturations during sleep.

No significant differences were found between Caucasians and African Americans in the risk for RLS.

Sex

In general, gender differences have been found in both circadian rhythm regulation and the homeostatic sleep process. Specifically, chronotype studies have found that men have a stronger tendency toward eveningness compared with women. Sex differences in the sleep-wake cycle appear to increase in response to sleep loss, suggesting different regulation of sleep homeostasis between men and women. Compared with men, women show more slow-wave sleep (SWS), more spindling activity during SWS, and slower age-related reduction of SWS.

Insomnia: Starting at puberty the incidence of insomnia in females differs from that of males. At puberty, insomnia rates for girls are almost triple that of boys. As women, the difference is augmented to a 41% greater risk for the development of insomnia as compared with men and by age 65 years, the risk is 73% greater as compared with men. Conditions such as bipolar disorder, stable coronary artery disease, and certain anxiety and depressive disorders that exhibit higher rates in women are associated with insomnia.

Obstructive sleep apnea: Women are more likely to have upper airway resistance syndrome (UARS), less likely to have positional apnea, and more likely to have REM-related OSA.

Narcolepsy: Men have a greater relative risk of narcolepsy with cataplexy (1.2:1).

Restless legs syndrome: Symptoms of RLS are more frequently reported by women. During pregnancy, prevalence rates have been reported between 11-23%

Age

• In general, sleep is sounder and less prone to disturbances in younger people. As women age, physical and hormonal changes take place that make sleep lighter and less sound. Women older than 40 years are 1.3 times more likely than age-matched men to report insomnia.
• In the years surrounding menopause, sleep disturbances occur with increased frequency. Women take longer to fall asleep, wake up more often at night, and are more tired during the day. Hot flashes and night sweats, associated with decreased levels of estrogen, may contribute to midsleep awakenings. The prevalence of SDB increases significantly after menopause.
• During postmenopausal years, sleep efficiency further decreases, and waking after sleep onset increases. Factors affecting sleep during this period include pain, certain medical and emotional conditions, and physical discomfort. Polysomnographic changes of elderly women include decreased slow-wave sleep stages 3 and 4, which results from decreased EEG amplitude, and shorter REM sleep latency. In one study, older women who slept more than 9 hours per night had higher risk of ischemic stroke.

Clinical

History

Taking a careful sleep history is an essential part of the evaluation of sleep disorders. This is particularly important for women who present with insomnia, as insomnia constitutes a symptom rather than a disorder and may be related to various problems, including psychiatric and medical conditions. Accurate differential diagnosis is essential before formulation of a treatment plan. The nature of the difficulty, the duration of symptoms, medical and psychiatric history, and careful assessment of current and previous sleep patterns are all essential pieces of information in the differential diagnosis.

• Nature of sleep difficulty: Women typically present with one or a combination of the following:
  • Difficulty falling asleep: The inability to fall asleep suggests psychophysiological or primary insomnia. Typically, this type of insomnia, often termed "learned" insomnia, is more frequent in younger individuals. It is characterized by an initial level of increased somatized and psychological tension, which may lead to occasional sleep disturbance and later may be reinforced by maladaptive behavior targeted at preventing the sleep disturbance. Often, a learned insomnia is associated with anxiety disorder, certain personality styles, and stressful lifestyle.
  • Difficulties maintaining sleep: Multiple awakenings during sleep are more frequent in older individuals and suggest major sleep disorders, such as OSA, PLMD, as well as other medical and psychiatric conditions. Older women who suffer from arthritis and other painful conditions, women on certain medications, and women in their last trimester of pregnancy are some of the groups likely to present with difficulties in maintaining sleep.
  • Excessive daytime sleepiness: In older postmenopausal women, excessive daytime sleepiness suggests SDB and PLMD. Severe sleepiness in young women is more likely to be associated with sleep deprivation or narcolepsy.
• Duration of symptoms
  • Typically, short acute sleep disorder is associated with an identifiable cause and almost always can be traced to an acute medical or psychological event.
  • Chronic insomnia often begins as an acute insomnia, which later develops into a chronic condition.
  • Understanding the patient's coping style and identifying measures that helped in the past may help identify the cause of the sleep problem.
• Sleep-wake pattern
  • Irregular sleep pattern may point to impaired sleep hygiene or a circadian rhythm disorder.
  • In delayed sleep phase syndrome, women consistently go to bed very late and are unable to get up in the morning.
  • Women who present with persistent early morning awakenings are more likely to suffer from depressive disorders.
  • Loud snoring and restless sleep suggest SDB.
  • Multiple brief awakening and periodic leg kicks indicate the possibility of PLMD.
• Medical and psychiatric history
  • This is an important part of sleep history and should include a thorough investigation of present and past medications that potentially can interfere with sleep, such as antihypertensive medication.
  • A number of medical conditions potentially can disturb sleep and need to be ruled out. These include chronic cardiac or lung disease, thyroid disease, gastroesophageal reflux, chronic pain, and other conditions.
  • Similarly, psychiatric history should include information regarding previous hospitalization, present and past use of psychoactive medication, and history of alcohol and drug abuse.
  • Insomnia, especially with early morning awakening, is one of the most common symptoms of depression. Women who suffer from anxiety disorder or chronic stress may also sleep poorly.
  • Women with sleep apnea often present with other concomitant sleep disorders such as restless legs syndrome and insomnia.
  • The relationship between sleep apnea and hypertension and between sleep apnea and insulin resistance render these conditions suspicious for OSA comorbidity.
• Family sleep history: Assessment of family history provides additional information regarding the causes of the sleep disorder. For example, family history of daytime sleepiness may point to a neurological sleep condition such as narcolepsy.
• Hormonal status: Low estrogen levels may be responsible for affective symptoms, including depressed mood, anxiety, fatigue, forgetfulness, and decreased concentration.
  • Premenstrual insomnia: Sleep disturbances have been described as part of a constellation of physical and emotional symptoms occurring during the premenstrual (late luteal) phase of the menstrual cycle, historically described as the premenstrual syndrome (PMS). Women who experience PMS report having sleep disturbances, including increased sleep latency and midsleep awakenings. They also report a significant increase in daytime sleepiness and increased difficulties in waking up.
    • Recently, the hormonal fluctuations of the menstrual cycle have been recognized as possible contributors to the pathophysiology of mood disorders. In a small percentage of women, severe symptoms associated with PMS, including sleep disturbances, mood lability, irritability, and anxiety, may interfere with daily activities and cause a mood disorder.
    • In its new definition, as PMDD, the syndrome is included in the 1994 Diagnostic and Statistical Manual of Mental Disorders, Fourth Revision (DSM-IV). Women with PMDD often show a pattern of advanced sleep phase with an earlier bedtime and early morning awakening.
  • Premenstrual hypersomnia: This is a rare sleep disorder, occurring in association with the menstrual period, and is characterized by pronounced daytime sleepiness, which typically begins a few days prior to the onset of menstruation and ends a few days after the onset of menstruation.
  • Sleep in pregnancy: During the first trimester, an increase in total sleep time and daytime sleepiness is noted, whereas decreased sleep time and increased number of nocturnal awakenings characterize the third trimester. The most common reasons for sleep disturbances given by pregnant women are frequent urination, heartburn, general discomfort, fetal movements, low back pain, leg cramps, and nightmares.
  • Sleep disorders in menopause
    • Insomnia: Difficulties with sleep onset and sleep maintenance are common in menopausal women. In cases of severe hot flashes, women can wake up several times during the night with a sensation of heat, increased heart rate, and, occasionally, a feeling of anxiety. In turn, sleep fragmentation associated with hot flashes can cause daytime fatigue, mood lability, irritability, and memory lapses. For some menopausal women who do not experience distressing vasomotor symptoms, insomnia may be associated with menopause-related mood syndrome.
    • SDB: Increased body mass and decreased endogenous estrogen and progesterone levels combined with loud snoring may increase the likelihood of upper airway obstruction, leading to SDB. Women with SDB are more likely than men to have insomnia complaints and frequently have concomitant depression and other major sleep disorders such as RLS.
    • Postmenopausal sleep disorders: As women age, sleep becomes lighter and more fragmented. While maintaining long hours of uninterrupted sleep becomes more difficult, maintaining long hours of wakefulness during the day also becomes more difficult. This can result in waking periods during the night and increased daytime fatigue. Compared to young people, older individuals go to sleep early in the evening and get up earlier in the morning. Health issues and chronic conditions together with the aging process can further disturb sleep. Arthritis and other painful conditions, chronic lung disease, certain medications, heartburn, and frequent trips to the bathroom have been shown to be detrimental to sleep continuation. The use of hypnotics increases with age, with usage by women significantly higher than that by age-matched men.
• Work and lifestyle: Those engaged in rotating and night shifts are likely to experience sleep problems. Women with inactive lifestyles may experience trouble falling asleep. Women who keep erratic schedules or those who go to sleep late on weekend nights and oversleep on weekend days are also more likely to have trouble resetting their body clock to a normal schedule during the week.
• Drugs and alcohol: Use of caffeine, nicotine, or other stimulating drugs near bedtime may prevent women from falling asleep. Alcohol, often used by women to help them fall asleep, may cause sleep fragmentation and nightmares.

Physical

The examination of the woman presenting with sleep problems addresses 2 major issues: psychological and physiological findings. General appearance and affect can be assessed early and during the examination. Chronic illness or chronic pain often is evinced in the general appearance and movement of a patient. The examination focuses on addressing any major medical illness that may be associated with sleep symptomatology, as well as on risk factors that direct toward evaluation of sleep-related disorders such as narcolepsy and OSA. Many patients with circadian rhythm disorders and insomnia may have normal physical examination findings.

• General appearance: This includes an assessment of nutritional status as well as body habitus. General care, personal hygiene, and social exchange can also be surveyed. Elderly patients with osteoporosis may be identified for further evaluation by their posture. Chronic pain associated with fractures can disrupt sleep.
• Vital signs: Hypertension has been associated with OSA.
• Head and neck examination: Inspection of the head can direct us to further evaluation for hyperthyroidism when exophthalmos is noted and evaluation of OSA when micrognathia or midfacial abnormalities are noted. Deviation of the nasal septum may also be associated with OSA. Myopathic facies is another example that suggests further evaluation of sleep-related breathing disorder, as do findings consistent with atopic disease. Large neck size associated with obesity is predictive of increased risk of OSA; however, a thorough examination of the neck is also indicated to evaluate for tumors.
• Chest: Chronic obstructive pulmonary disease and congestive heart failure are frequent causes of poor sleep in older patients. Inspection, auscultation, palpation, and percussion are all important elements of the examination. Digital clubbing is associated with chronic cardiac and pulmonary disease, but this may also be familial.
• Abdomen: Excessive obesity and advanced pregnancy can affect breathing during sleep, especially in the supine position. Abdominal masses and tumors, depending on size and location, may also be problematic.
• Neurologic examination: Patients with organic brain syndromes, dementia, or Alzheimer disease often have sleep abnormalities. Neuromuscular disease, such as spinal muscle atrophy, can be associated with hypoventilation during sleep and increased daytime sleepiness.

Causes

Major factors that play a role in causing sleep disturbances in women include the following:

• Hormonal changes: Both estrogen and progesterone influence sleep and possibly daytime sleepiness. Thus, sleep disturbances are more common during the premenstrual period and again later in life during postmenopausal years when hormonal changes are pronounced. In addition, decreased level of estrogen during menopause has been associated with increased upper airway resistance, snoring, and OSA.
• Psychosocial issues: In today's society, many women cope with multiple roles in their families. With less time for themselves, they often cut back on sleep. In addition to sleep deprivation, increased stress has been associated with sleep-onset insomnia.
• Psychiatric disorders: Mood disorders are more prevalent in women than in men, primarily those that are unique to the female reproductive system (eg, PMDD, pregnancy affective disorder, postpartum depression, perimenopausal mood disorder). While anxiety disorders often are associated with trouble falling asleep, depression typically is associated with early morning awakening.
• Age: The frequency and severity of major sleep disorders, such as SDB, RLS, and PLMD, increase with age.
• Weight: Obesity plays an important role in the pathophysiology of SDB. RLS has also been shown to have a correlation with body mass index.

• Search for CME/CE on This Topic »

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