Disturbed dreaming during the third trimester of pregnancy

Highlights

• We prospectively and comparatively assess the recall of dreaming and of disturbed dreaming in late pregnancy.

• Pregnant women report prospectively more bad dreams.

• More pregnant women than non-pregnant women report a nightmare incidence exceeding moderately severe pathology (>1/week).

• Higher prospective recall of bad dreams and nightmares both correlate with lower sleep quality in pregnant women.

Abstract

Objective

The majority of women develop sleep impairments during pregnancy, but alterations in dream experiences remain poorly understood. This study aimed to assess prospectively and comparatively the recall of dreaming and of disturbed dreaming in late pregnancy.

Methods

Fifty-seven nulliparous, third-trimester pregnant women (mean age ± SD, 28.7 ± 4.06 years) and 59 non-pregnant controls (mean age ± SD, 26.8 ± 4.21 years) completed demographics and psychological questionnaires. A 14-day prospective home log assessed sleep and dream characteristics and the Sleep Disorders Questionnaire measured retrospective dream and disturbed dream recall.

Results

Even though pregnant and non-pregnant women showed similar prospective dream recall (P = 0.47), pregnant women reported prospectively more bad dreams (P = 0.004). More pregnant women (21%) than non-pregnant women (7%) reported a nightmare incidence exceeding moderately severe pathology (>1/week) (P = 0.03). Pregnant women also reported overall lower sleep quality (P = 0.007) and more night awakenings (P = 0.003). Higher prospective recall of bad dreams (r = −0.40, P = 0.002) and nightmares (r = −0.32, P = 0.001) both correlated with lower sleep quality in pregnant women.

Conclusions

Late pregnancy is a period of markedly increased dysphoric dream imagery that may be a major contributor to impaired sleep at this time. Further polysomnographic assessments of pregnant women are needed to clarify relationships between sleep and disturbed dream production in this population.

Introduction

The rapidly changing physical, psychological and sociocultural circumstances of pregnancy often engender disturbances in sleep patterns [1]. The numerous hormonal and physiologic changes, in particular, heighten the risk of developing insomnia, restless legs syndrome, and sleep-disordered breathing symptoms [2]. Although not all pregnant women develop clinical sleep disorders, most display subjective and objective changes in sleep, such as lower sleep quality, shorter sleep duration, and lighter and more frequently interrupted sleep. These symptoms worsen with advancing gestational age [2], [3] – particularly among primigravidae women [4], [5].

Whether the cognitive features of sleep, such as dream experiences, are also altered or disturbed during pregnancy is still poorly understood. Bad dreams (disturbing dreams (DD) that do not awaken the dreamer [6], [7]) and nightmares (DD that trigger an awakening [8], [9]) are among the most prevalent DD in the general population: about 85% of adults report at least one nightmare per year, whereas bad dreams are four times more frequent than nightmares (see [9], [10] for reviews). Converging clinical evidence suggests that dreams are more easily recalled during pregnancy and, more importantly, that dream imagery is more frightening than during any other period of life [11], [12]. The increases in dream production and in DD frequency during pregnancy might be due to hormonal and physiologic changes, or they may be triggered by concomitant psychological changes, such as enhanced introspection and growing concerns about the childbearing process and motherhood. One possibility is that a precipitous increase in emotional concerns or ‘affect load’ during pregnancy results in an increase in DD at this time [9], [10].

However, existing studies on the subject of dreams and DD during pregnancy have produced numerous inconsistencies. For example, a comparative study found the proportions of pregnant (91%) and non-pregnant (86%) women able to report dreams to be similar [13]; this finding appears inconsistent with findings from a qualitative study that 80% of new mothers report their dreams to be particularly vivid, bizarre and detailed during pregnancy, and that some of these dreams were disturbing enough to incite them to change their daytime behaviors [1].

Studies have also reported a wide range of DD estimates depending on the time-frame, the collection methods, and the definitions used.

Two early descriptive studies suggest that dreams are commonly disturbed during pregnancy and that they reflect a woman’s concerns about the childbearing process. The first, a prospective study, found that 40% of dreams collected primarily during the third trimester were scored by independent judges to be nightmares, i.e., to contain very negative feelings ranging from fear to abject terror [14]. This definition is more liberal than the more common definition that considers nightmares to trigger an awakening, so bad dreams were likely also included in this estimate. Nonetheless, a second, self-report, study found that an exceptionally high proportion (25%) of pregnant women between seven and 42 weeks of gestation recalled at least one terrifying dream about pregnancy or the infant [15].

In contrast, four controlled self-report studies suggest that nightmares are not so common during pregnancy. Over a one-month period, pregnant women of all trimesters were awakened by frightening dreams or nightmares as frequently as were postpartum women [16]. Two other studies found third-trimester pregnant women to report bad dreams as frequently as did non-pregnant women [17], and to report fewer nightmares than they did earlier during pregnancy or pre-pregnancy [18]. Finally, new mothers were less likely to recall a nightmare from the entire pregnancy than were non-pregnant women to recall them from the last three months (56% vs 79%, respectively) [13].

The task of integrating the results of the previously reviewed studies is complicated by the fact that the assessment methods and types of estimates differ widely from one study to another. No research has prospectively measured and compared clearly defined bad dream or nightmare frequencies during any specific trimesters of pregnancy. Almost all studies reviewed here used retrospective self-assessment methods which often underestimate DD recall frequencies [6].

The question of DD during pregnancy is of major concern for women’s health. Whereas DD constitute a substantial sleep disturbance in frequent nightmare sufferers [19], [20], [21], sleep disturbances in turn predict adverse maternal and fetal outcomes, such as postnatal depression, preterm birth, lower birth weight, and longer labour durations [22], [23], [24], [25], [26], [27], [28]. Therefore, a more thorough evaluation of dream disturbances and their contributions to sleep impairment during pregnancy are warranted.

Accordingly, this study aimed to compare primigravidae pregnant women to non-pregnant women on prospective and retrospective measures of dream recall (DR), bad dream recall (BDR) and nightmare recall (NR). Groups were also compared for evidence of associations between DD and other symptoms of disturbed sleep.