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 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="" br="">
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 non progressing latent phase labour to induce sleep. It has been observed that on awakening the contractions are more regular and active.


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