Sleep disorders in pregnancy

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 group were 53% and 12% (p<0 .001="" 2011="" al="" br="" eid="" et="">
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) during pregnancy, the prevalence is even higher.

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,women younger than 20 or older than 35 or women who are overweight, have a history or hypertension or kidney disease or diabetes. Recent studies indicate that OSA per se is an independent risk factor for gestational hypertension/pre-eclampsia and may contribute to other poor obstetrical outcomes. Good blood pressure control in pregnancy is important. Continuous Positive Airway Pressure (CPAP), which is used to treat OSA, may also have beneficial effects on blood pressure (Champagne et al, 2010). It may therefore be very useful in patients with PIH as this condition is associated with both increased blood pressure and a significantly narrowed upper airways and limited airflow during sleep (Izci et al, 2003). Continuation of treatment for OSA following the pregnancy may also be required.

Insomnia is a sleep disorder which is characterised by a difficulty in initiating or maintaining sleep in combination with adverse daytime consequences. The daytime effects may include excessive fatigue, impairment of performance or emotional changes. Data from self-reported questionnaires suggests that sleep complaints are more frequent in pregnancy and that sleep disturbances increases as the pregnancy progresses. In a recent study of 300 women (100 women in each trimester of pregnancy) it was observed that there was a significant increase in insomnia in the 2nd trimester, excessive daytime sleepiness (EDS) was also increased in pregnancy and the rate for specific awakenings increased by 63% in the first trimester, by 80% in the second trimester and by 84% in the third trimester (p<0 .001="" 2004="" al="" br="" et="" opes="">
Restless leg syndrome is a neurosensory sleep disorder which begins in the evening. The associated symptomatic leg movements can prevent a person from falling asleep and contribute to poor sleep quality. Pregnant women have at least two or three times higher risk of experiencing restless legs syndrome (RLS) than the general population and women affected by pre-existing RLS often complain of worsening symptoms during pregnancy. It is associated with iron deficiency anaemia. 

The women who are most at risk are those with low folate, ferritin or haemoglobin prior to conception. Data from the existing epidemiological studies suggests that the rates may be as high as 27% in the third trimester(Lee et al, 2001; Manconi et al, 2004). Whilst RLS is a reversible syndrome in pregnancy and is typically limited to the third trimester it has been associated with adverse pregnancy outcomes and therefore needs to be taken seriously. The standard medications for RLS that contain dopaminergics or opioids should be avoided but preventative measures to increase the amount of folate should be encouraged at the first prenatal visit.

Complaints of heartburn increase during pregnancy and if these progress to severe nocturnal oesophageal reflux may also contribute to sleep disruption.


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