**1. Introduction**

There are many factors that can influence an individual's sleep pattern and quantity and quality of sleep. These factors can be cultural, social, psychological, behavioural, pathophysiological and environmental. Sleep patterns can also be influenced by society and by changes within society. In recent times we have seen the introduction of longer working hours, more shift-work and 24-7 availability of commodities. At the same time secular trends of curtailed duration of sleep to fewer hours per day across westernized populations (Akerstedt & Nilsson 2003) has led to increased reporting of fatigue, tiredness and excessive daytime sleepiness (Bliwise, 1996). It is of interest that whilst some studies indicate that women may have better sleep than men in general (Lindberg et al, 1997; Goel et al, 2005), they also report a larger difference in the estimated time of sleep that they believe they require and the actual sleep time they achieve than men. This might indicate that their sleep debt (amount of sleep deprivation) is higher in women than in men (Lindberg et al, 1997). There is now a wealth of evidence to support the epidemiological link between quantity of sleep (short and long duration) and quality of sleep (like difficulties in falling asleep or of maintaining sleep) and cardiovascular risk factors. These include hypertension (Cappuccio et al, 2007; Stranges et al, 2010), type-2 diabetes (Cappuccio et al, 2010a) and obesity (Cappuccio et al, 2008; Stranges et al, 2008; Cappuccio et al 2011a) as well as cardiovascular outcomes (Cappuccio et al, 2011b) and all-cause mortality (Ferrie et al, 2007; Cappuccio et al, 2010b). Additionally, there may be important gender differences in sleep and associated health outcomes (Miller, 2009 et al; Cappuccio et al, 2007). The deleterious effects of sleep deprivation can be seen on a variety of systems within the body, with detectable changes in metabolic (Knutson, et al. 2007; Spiegel, et al. 2009), endocrine (Spiegel, et al. 1999; Taheri, et al. 2004) and immune pathways (Miller & Cappuccio 2007; Miller et al, 2009).

The physiological and hormonal changes that occur in pregnancy increase the risk of developing Sleep Disordered Breathing (SDB). It has been estimated that 10-27% of pregnant women may suffer from habitual snoring (Pien & Schwab, 2004) and there is growing evidence to suggest that snoring and sleep apnoea during pregnancy are associated with an increased risk of gestational hypertension and pre-eclampsia. SDB and short sleep duration in pregnant women may also be associated with the risk of gestational diabetes.

Sleep and Pregnancy: Sleep Deprivation,

(Facco et al, 2010).

Sleep Disturbed Breathing and Sleep Disorders in Pregnancy 3

weight gain, low annual family income, and single motherhood (P < 0.01). A weak but not significant effect of season on sleep scores was recorded: The mean PSQI scores were 6.06 (+/-3.96) in winter, 5.21 (+/-3.21) in spring) 5.33 (+/-3.04) in summer and 5.53 (+/-2.41) in autumn); (P=0.076). In a similar study of 189 nulliparous women Facco et al demonstrated that compared with the baseline assessment (mean gestational age (13.8 (+/-3.8)) the mean sleep duration was significantly shorter at 30.0 (+/-2.2) weeks gestation (p<0.01). They also observed that in the third trimester the proportion of patients who reported frequent snoring (at least three nights per week) was significantly increased, and that there was an increase in those who met the diagnostic criteria for the recognised sleep disorder 'restless leg syndrome'. Furthermore, poor sleep quality, as defined by a Pittsburgh Sleep Quality Index score greater than 5, became significantly more common as pregnancy progressed

In a separate study Wilson et al also found that sleep efficiency was decreased in late pregnancy and was associated with an increase in cortical arousals when compared to women in early pregnancy and non-pregnant women. Compared to a control group, they found that women in the third trimester of pregnancy had more awakenings and had had poorer sleep efficiency. They had less stage 4 sleep and more stage 1 sleep and spent less

Sleep quality also decreases as a woman approaches labour (Evans et al, 1995) but whilst little is known of the effect of sleep disturbance on labour or delivery outcome it has been common practice to administer morphine sulphate to women in either early or nonprogressing latent phase labour to induce sleep. It has been observed that on awakening the

Sleep-Disordered breathing (SDB) is the term used to describe a group of disorders which are characterized by abnormalities of respiratory pattern (pauses in breathing) or the quantity of ventilation during sleep. A recent study evaluated the frequency of sleep disordered breathing in women with gestational hypertension compared to healthy women with uncomplicated pregnancies. They observed that women with gestational hypertension may have a significantly higher frequency of sleep disordered breathing than do healthy women with uncomplicated pregnancies of similar gestational age. The frequencies of sleep disordered breathing in the more obese gestational hypertension group and the healthy

Obstructive sleep apnoea (OSA) is the most common of these sleep disorders and is characterized by the complete or partial collapse of the pharyngeal airway during sleep. To resume ventilation, feedback mechanisms arouse the individual, which leads to sleep disruption. OSA is associated with an increased CVD risk. Although, men are twice as likely to develop OSA as women, the risk is increased in women if they are overweight. Moreover, data from recent studies indicates that snoring and OSA increase during pregnancy. The prevalence of OSA is very low in normotensive women low-risk pregnancies but is increased among normotensive pregnant women with high risk pregnancies and, in those with gestational hypertension (pregnancy-induced hypertension (PIH)/pre-eclampsia)

PIH is characterised by high blood pressure with a flat circadian rhythm and in particular does not have the normal nocturnal dip associated with sleep. Risk factors for PIH include first time pregnancy, long periods (>10years) between pregnancies, multiple pregnancies,

time in rapid eye movement (REM) sleep (Wilson et al, 2010).

contractions are more regular and active.

group were 53% and 12% (p<0.001) (Reid et al, 2011).

during pregnancy, the prevalence is even higher.

**2.2 Sleep disorders in pregnancy** 

This chapter will examine the evidence that suggests that short sleep duration and poor quality are associated with adverse maternal and foetal outcomes. Furthermore, it will examine the potential mechanisms which may underlie these associations including activation of the sympathetic nervous system, oxidation and inflammation and mechanisms leading to the development of insulin resistance (Izci-Balserak & Pien, 2010). It will also consider the prevalence of sleep disorders in pregnancy. The diagnosis, management and treatment of sleep disorders in pregnancy will be discussed along with implications for public health policy, etc.

## **2. Sleep and pregnancy**

Pregnancy is associated with many maternal physiological and psychological changes both of which may have an effect on sleep. In the first trimester, hormonal changes may disrupt sleep and in the third trimester the large baby and the anxiety regarding delivery may have associated effects on sleep. Likewise post-partum, a newborn may disrupt sleep patterns. The review by Lee in 1998 demonstrated that there was a paucity of studies, which addressed the alterations of sleep in pregnant women, moreover many of these studies lacked sufficient power to allow consistent interpretation and replication of the results (Lee, 1998). Since then a number of studies have now been conducted but more research is still required to establish whether for example, a woman's pre-pregnancy sleep pattern can affect outcome and to determine whether there is any effect of parity on sleep related maternal and foetal outcomes. The changes in circadian rhythm of various hormones and the associated changes to sleep architecture that occur throughout pregnancy are discussed by Wolfson and Lee (2005) in 'The Principles and Practice of Sleep Medicine' (Kryger, Roth and Dement (Eds)).

#### **2.1 Sleep deprivation: Adverse sleep changes in pregnancy quantity and quality**

Due to the lack of good longitudinal studies there is still little information on what constitutes normal sleep quality and quantity both during pregnancy and in the period following delivery. In a recent study however Signal et al quantified the change and variability in sleep duration and quality across pregnancy and post-partum in 8 healthy nulliparous and 11 healthy multiparous women (Signal et al, 2007). The women wore an actigraph and completed a sleep diary for seven nights during the second trimester, one week prior to delivery, and at one and six weeks post-partum. They observed that compared to multiparous women, nulliparous women generally had less efficient sleep, spent more time in bed and had greater wake after sleep onset in the second trimester, and spent less time in bed and had fewer sleep episodes a day at one week post-partum. The largest change in sleep however occurred during the first week after delivery with the women obtaining 1.5h less sleep than during pregnancy. In a more recent and larger study sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI) in 260 women during the second and third trimester of pregnancy (Naud et al, 2010). Of the 260 women, 192 (73.6%) had a term delivery without any adverse outcome. The investigators reported that there were no differences in sleep parameters between pregnancies with adverse outcome and without adverse outcome. The PSQI scores however indicted that sleep quality deteriorated from the second (5.26 +/- 3.16) to the third trimester (6.73 +/- 4.02; P < 0.01). This deterioration was displayed in five of seven sleep components (P < 0.01). Scores in the "poor sleeper" range were recorded by 36% of women in the second trimester and 56%, of women in the third (P < 0.01). "Poor sleep" in both trimesters was associated with low or high

This chapter will examine the evidence that suggests that short sleep duration and poor quality are associated with adverse maternal and foetal outcomes. Furthermore, it will examine the potential mechanisms which may underlie these associations including activation of the sympathetic nervous system, oxidation and inflammation and mechanisms leading to the development of insulin resistance (Izci-Balserak & Pien, 2010). It will also consider the prevalence of sleep disorders in pregnancy. The diagnosis, management and treatment of sleep disorders in pregnancy will be discussed along with implications for

Pregnancy is associated with many maternal physiological and psychological changes both of which may have an effect on sleep. In the first trimester, hormonal changes may disrupt sleep and in the third trimester the large baby and the anxiety regarding delivery may have associated effects on sleep. Likewise post-partum, a newborn may disrupt sleep patterns. The review by Lee in 1998 demonstrated that there was a paucity of studies, which addressed the alterations of sleep in pregnant women, moreover many of these studies lacked sufficient power to allow consistent interpretation and replication of the results (Lee, 1998). Since then a number of studies have now been conducted but more research is still required to establish whether for example, a woman's pre-pregnancy sleep pattern can affect outcome and to determine whether there is any effect of parity on sleep related maternal and foetal outcomes. The changes in circadian rhythm of various hormones and the associated changes to sleep architecture that occur throughout pregnancy are discussed by Wolfson and Lee (2005) in 'The

Principles and Practice of Sleep Medicine' (Kryger, Roth and Dement (Eds)).

**2.1 Sleep deprivation: Adverse sleep changes in pregnancy quantity and quality**  Due to the lack of good longitudinal studies there is still little information on what constitutes normal sleep quality and quantity both during pregnancy and in the period following delivery. In a recent study however Signal et al quantified the change and variability in sleep duration and quality across pregnancy and post-partum in 8 healthy nulliparous and 11 healthy multiparous women (Signal et al, 2007). The women wore an actigraph and completed a sleep diary for seven nights during the second trimester, one week prior to delivery, and at one and six weeks post-partum. They observed that compared to multiparous women, nulliparous women generally had less efficient sleep, spent more time in bed and had greater wake after sleep onset in the second trimester, and spent less time in bed and had fewer sleep episodes a day at one week post-partum. The largest change in sleep however occurred during the first week after delivery with the women obtaining 1.5h less sleep than during pregnancy. In a more recent and larger study sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI) in 260 women during the second and third trimester of pregnancy (Naud et al, 2010). Of the 260 women, 192 (73.6%) had a term delivery without any adverse outcome. The investigators reported that there were no differences in sleep parameters between pregnancies with adverse outcome and without adverse outcome. The PSQI scores however indicted that sleep quality deteriorated from the second (5.26 +/- 3.16) to the third trimester (6.73 +/- 4.02; P < 0.01). This deterioration was displayed in five of seven sleep components (P < 0.01). Scores in the "poor sleeper" range were recorded by 36% of women in the second trimester and 56%, of women in the third (P < 0.01). "Poor sleep" in both trimesters was associated with low or high

public health policy, etc.

**2. Sleep and pregnancy** 

weight gain, low annual family income, and single motherhood (P < 0.01). A weak but not significant effect of season on sleep scores was recorded: The mean PSQI scores were 6.06 (+/-3.96) in winter, 5.21 (+/-3.21) in spring) 5.33 (+/-3.04) in summer and 5.53 (+/-2.41) in autumn); (P=0.076). In a similar study of 189 nulliparous women Facco et al demonstrated that compared with the baseline assessment (mean gestational age (13.8 (+/-3.8)) the mean sleep duration was significantly shorter at 30.0 (+/-2.2) weeks gestation (p<0.01). They also observed that in the third trimester the proportion of patients who reported frequent snoring (at least three nights per week) was significantly increased, and that there was an increase in those who met the diagnostic criteria for the recognised sleep disorder 'restless leg syndrome'. Furthermore, poor sleep quality, as defined by a Pittsburgh Sleep Quality Index score greater than 5, became significantly more common as pregnancy progressed (Facco et al, 2010).

In a separate study Wilson et al also found that sleep efficiency was decreased in late pregnancy and was associated with an increase in cortical arousals when compared to women in early pregnancy and non-pregnant women. Compared to a control group, they found that women in the third trimester of pregnancy had more awakenings and had had poorer sleep efficiency. They had less stage 4 sleep and more stage 1 sleep and spent less time in rapid eye movement (REM) sleep (Wilson et al, 2010).

Sleep quality also decreases as a woman approaches labour (Evans et al, 1995) but whilst little is known of the effect of sleep disturbance on labour or delivery outcome it has been common practice to administer morphine sulphate to women in either early or nonprogressing latent phase labour to induce sleep. It has been observed that on awakening the contractions are more regular and active.
