Foreword

Abstract

Across the lifespan of women, reproductive cycles can significantly affect sleep. In general, women appear to describe more subjective complaints of unsatisfactory sleep quality, as well as non-restorative sleep, but also tend to report a greater need for sleep compared to men. During the menstrual cycle, sleep quality is commonly poorer immediately before and during the initial part of menstruation. Duration of nighttime sleep is also longer prior to menses. Many factors potentially contribute to sleep disturbance during this time, including mood changes and physical complaints (eg, breast tenderness, abdominal bloating, cramping, and headaches). The luteal phase of the menstrual cycle is associated with increased subjective sleepiness, as well as decreased sleep efficiency and more prolonged sleep latency. There is also commonly an increase in non-rapid eye movement (NREM) stage 2 sleep, increase in frequency of sleep spindles, and decrease in rapid eye movement (REM) sleep during the luteal phase as compared to the follicular phase. Menstruation itself can be accompanied by an increase in latency to slow-wave sleep. Specific sleep disturbances can also develop during the menstrual cycle, secondary to dysmenorrhea (painful uterine cramping), endometriosis (presence of endometrial tissue in the pelvis or abdomen), premenstrual syndrome, and premenstrual dysphoric disorder. Dysmenorrhea can result in diminished sleep quality and duration of REM sleep. Sleep can be disturbed by pain from endometriosis. Premenstrual syndrome (PMS) is characterized by bloating, irritability, and fatigue that develop prior to menses during the late luteal phase. PMS can be associated with poor sleep, frequent awakenings, unpleasant dreams, and complaints of insomnia or excessive sleepiness. Considered a more severe form of PMS, premenstrual dysphoric disorder can also be complicated by complaints of insomnia or excessive sleepiness, along with functional impairment and mood changes. Finally, parasomnias, including sleepwalking and sleep terrors, occurring repeatedly during the luteal phase of menstruation have been described. The use of oral contraceptives can also produce significant changes in NREM stage 2 sleep and decreases in REM sleep latency; however, no changes in daytime alertness have been noted with oral contraceptive use. Sleep quality and duration are profoundly affected by pregnancy. Increase in frequency of awakenings and wake time after sleep onset, as well as decrease in nighttime sleep duration and increase in daytime napping, can occur as early as the first trimester of pregnancy. Sleep tends to improve during the second trimester, only to significantly deteriorate again during the final months of pregnancy. Causes of sleep disturbance during pregnancy vary from one individual to the next but may be due to a combination of any of the following factors: breast tenderness, dyspnea, nausea, urinary frequency, fetal movements, leg cramps, or anxiety. Sleep-related breathing disorders, including snoring and obstructive sleep apnea, and restless legs syndrome may be precipitated or aggravated by pregnancy. Excessive sleepiness may extend into the postpartum period, and mothers may experience significant sleep loss, changes in mood, and frequent napping. Finally, peri-menopausal and post-menopausal phases with their declining levels of estrogen and progesterone, and irregular menstrual cycles can lead to the development of hot flashes, night sweats, headaches, and urinary frequency; these, in turn, can give rise to excessive sleepiness, sleep fragmentation, and insomnia. In addition to insomnia, obstructive sleep apnea also has a higher prevalence during this period compared to the pre-menopausal period.