Comparisons of sleep patterns between mothers in post-partum from 9 to 12 weeks and non-pregnant women

Hypocretins, sleep, and maternal behavior

The postpartum period is a demanding time during which mothers experience numerous physiological adaptations that enable them to care for their offspring while maintaining their wellbeing. Hypocretins, also known as orexins, are neuropeptides synthesized by hypothalamic neurons that play a fundamental role in several functions, including the promotion of wakefulness and motivated behaviors, such as maternal care. In this regard, several findings suggest that the activity of the hypocretinergic system increases in the early postpartum period and begins to decline as weaning approaches. In particular, hypocretins within the medial preoptic area, a crucial region during this period, modulate both maternal behavior and sleep. Although further studies are necessary to obtain a comprehensive understanding of the role of hypocretins in lactating females, current research suggests that this system participates in promoting active components of maternal behavior and regulating wakefulness and sleep adjustments during the postpartum period, potentially leading to increased wakefulness during this stage. These adaptive adjustments enable the mother to cope with the continuously changing demands of the pups.

Prevalence of Poor Sleep Quality in Perinatal and Postnatal Women: A Comprehensive Meta-Analysis of Observational Studies

BACKGROUND

Sleep disturbance is common in perinatal and postnatal women, but the epidemiology of sleep problems is highly variable in these populations. This was a meta-analysis that examined the prevalence of poor sleep quality and its correlates among perinatal and postnatal women.

METHODS

A systematic search of both international and Chinese databases (PubMed, EMBASE, PsycINFO, Web of Science, CNKI, and Wangfang) was performed. Studies with data on sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI) were included.

RESULTS

Forty-two studies were included for analyses. The prevalence of poor sleep quality was 54.2% (95% CI: 47.9-60.5%) in perinatal and postnatal women, with 44.5% (95% CI: 37.6-51.6%) in perinatal women and 67.2% (95% CI: 57.6-75.5%) in postnatal women. The pooled total PSQI score was 7.54 ± 0.40 (95% CI: 6.75-8.33), while the average PSQI component scores varied from 0.13 ± 0.04 for use of sleeping medication to 1.51 ± 0.17 for habitual sleep efficiency. Maternal age, study site, survey year, comorbidity, PSQI cut-off value, and quality assessment score had significant moderating effects on the prevalence of poor sleep quality.

CONCLUSION

Given the negative impact of poor sleep quality on health outcomes and well-being, regular screening for poor sleep quality and effective interventions should be conducted for this population.

Maternal and infant activity: Analytic approaches for the study of circadian rhythm

The study of infant and mother circadian rhythm entails choice of instruments appropriate for use in the home environment as well as selection of analytic approach that characterizes circadian rhythm. While actigraphy monitoring suits the needs of home study, limited studies have examined mother and infant rhythm derived from actigraphy. Among this existing research a variety of analyses have been employed to characterize 24-h rhythm, reducing ability to evaluate and synthesize findings. Few studies have examined the correspondence of mother and infant circadian parameters for the most frequently cited approaches: cosinor, non-parametric circadian rhythm analysis (NPCRA), and autocorrelation function (ACF). The purpose of this research was to examine analytic approaches in the study of mother and infant circadian activity rhythm. Forty-three healthy mother and infant pairs were studied in the home environment over a 72h period at infant age 4, 8, and 12 weeks. Activity was recorded continuously using actigraphy monitors and mothers completed a diary. Parameters of circadian rhythm were generated from cosinor analysis, NPCRA, and ACF. The correlation among measures of rhythm center (cosinor mesor, NPCRA mid level), strength or fit of 24-h period (cosinor magnitude and R(2), NPCRA amplitude and relative amplitude (RA)), phase (cosinor acrophase, NPCRA M10 and L5 midpoint), and rhythm stability and variability (NPCRA interdaily stability (IS) and intradaily variability (IV), ACF) was assessed, and additionally the effect size (eta(2)) for change over time evaluated. Results suggest that cosinor analysis, NPCRA, and autocorrelation provide several comparable parameters of infant and maternal circadian rhythm center, fit, and phase. IS and IV were strongly correlated with the 24-h cycle fit. The circadian parameters analyzed offer separate insight into rhythm and differing effect size for the detection of change over time. Findings inform selection of analysis and circadian parameters in the study of maternal and infant activity rhythm.

No effect of oral L-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk

Postpartum depression (PPD) is the most common complication of childbearing with a 13% prevalence rate. Sleep disturbances are also common, particularly during early postpartum. In theory, l-tryptophan could improve sleep and reduce depressed mood in early postpartum; however, the first step in clinical development of tryptophan for use in postpartum is to measure the effect of oral l-tryptophan on its concentrations in breast milk, which is presently unknown. The aims were to investigate the effect of oral l-tryptophan and alpha-lactalbumin, a protein with high tryptophan concentration, on total and free tryptophan levels in breast milk and plasma, and to compare free tryptophan levels in breast milk with those in common infant formulas. Thirty healthy breastfeeding women were randomly allocated to receive 2g or 4g of l-tryptophan, or, 20g or 40g of alpha-lactalbumin or no supplement. Free tryptophan levels were also measured in 12 different infant formulas. Total tryptophan in breast milk was unaffected by oral administration of l-tryptophan or alpha-lactalbumin (repeated measures of ANOVA (rANOVA), group effect: p=0.93). Both l-tryptophan and alpha-lactalbumin were associated with greater free tryptophan levels in breast milk (rANOVA, group effect: p<0.001) (representing 2% of total tryptophan), but these concentrations were within the range of commonly used infant formulas. In contrast to most sleep inducing medications, l-tryptophan does not affect its total concentration in breast milk. These results support further investigation of dietary l-tryptophan and alpha-lactalbumin as part of a dietary supplementation approach to address sleep disturbances in postpartum and reduce risk of PPD.

Sleep and sleepiness among first-time postpartum parents: a field- and laboratory-based multimethod assessment

The study aim was to compare sleep, sleepiness, fatigue, and neurobehavioral performance among first-time mothers and fathers during their early postpartum period. Participants were 21 first-time postpartum mother-father dyads (N = 42) and seven childless control dyads (N = 14). Within their natural environment, participants completed 1 week of wrist actigraphy monitoring, along with multi-day self-administered sleepiness, fatigue, and neurobehavioral performance measures. The assessment week was followed by an objective laboratory-based test of sleepiness. Mothers obtained more sleep compared to fathers, but mothers' sleep was more disturbed by awakenings. Fathers had greater objectively measured sleepiness than mothers. Mothers and fathers did not differ on subjectively measured sleep quality, sleepiness, or fatigue; however, mothers had worse neurobehavioral performance than fathers. Compared to control dyads, postpartum parents experienced greater sleep disturbance, sleepiness, and sleepiness-associated impairments. Study results can inform social policy, postpartum sleep intervention development, and research on postpartum family systems and mechanisms that propagate sleepiness.

Sleep and depression in postpartum women: a population-based study

STUDY OBJECTIVES

(1) To describe the prevalence of and risk factors for postpartum maternal sleep problems and depressive symptoms simultaneously, (2) identify factors independently associated with either condition, and (3) explore associations between specific postpartum sleep components and depression.

DESIGN

Cross-sectional.

SETTING

Population-based.

PARTICIPANTS

All women (n = 4191) who had delivered at Stavanger University Hospital from October 2005 to September 2006 were mailed a questionnaire seven weeks postpartum. The response rate was 68% (n = 2830).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Sleep was measured using the Pittsburgh Sleep Quality Index (PSQI), and depressive symptoms using the Edinburgh Postnatal Depression Scale (EPDS). The prevalence of sleep problems, defined as PSQI > 5, was 57.7%, and the prevalence of depression, defined as EPDS > or = 10, was 16.5%. The mean self-reported nightly sleep duration was 6.5 hours and sleep efficiency 73%. Depression, previous sleep problems, being primiparous, not exclusively breastfeeding, or having a younger or male infant were factors associated with poor postpartum sleep quality. Poor sleep was also associated with depression when adjusted for other significant risk factors for depression, such as poor partner relationship, previous depression, depression during pregnancy and stressful life events. Sleep disturbances and subjective sleep quality were the aspects of sleep most strongly associated with depression.

CONCLUSIONS

Poor sleep was associated with depression independently of other risk factors. Poor sleep may increase the risk of depression in some women, but as previously known risk factors were also associated, mothers diagnosed with postpartum depression are not merely reporting symptoms of chronic sleep deprivation.

Subjective and objective sleep among depressed and non-depressed postnatal women

OBJECTIVE

Women sleep less in the postnatal period and it has been suggested that mothers diagnosed with depression alternatively could be suffering from the effects of chronic sleep deprivation.

METHOD

From a population-based study, we recruited 42 women, of whom 21 scored >or=10 on the Edinburgh Postnatal Depression Scale. Sleep was registered by the Pittsburgh Sleep Quality Index (PSQI), sleep diaries and actigraphy 2 months after delivery.

RESULTS

There were significant differences in subjective sleep measured retrospectively by the PSQI between depressed and non-depressed women. In contrast, there were no significant differences in sleep measured prospectively by sleep diaries and actigraphy. Both depressed and non-depressed women had impaired sleep efficiency (82%) and were awake for about 1.5 h during the night. Primipara had worse sleep, measured by actigraphy, compared with multipara.

CONCLUSION

Measured objectively and prospectively, women with depression did not have worse sleep than non-depressed women.

Sleep, rhythms and women's mood. Part I. Menstrual cycle, pregnancy and postpartum

This review summarizes studies of sleep and other biological rhythms during the menstrual cycle, pregnancy and the postpartum period, focusing, where feasible, on studies in women who met DSM-IV (Diagnostic and Statistical Manual for Mental Disorders, 4th edition) criteria for a depressive disorder compared with healthy controls. The aim was to review supporting evidence for the hypothesis that disruption of the normal temporal relationship between sleep and other biological rhythms such as melatonin, core body temperature, cortisol, thyroid stimulating hormone (TSH) or prolactin occurring during times of reproductive hormonal change precipitates depressive disorders in predisposed women. Treatment strategies, designed to correct these altered phase (timing) or amplitude abnormalities, thereby improve mood. Although there may be some common features to premenstrual, pregnancy and postpartum depressive disorders (e.g. elevated prolactin levels), a specific profile of sleep and biological rhythms distinguishes healthy from depressed women during each reproductive epoch. Further work is needed to characterize more fully the particular abnormalities associated with each reproductive state to identify common versus distinctive features for each diagnostic group. This information could serve as the basis for developing more targeted treatment strategies.

Diurnal levels of Fos immunoreactivity are elevated within hypocretin neurons in lactating mice

The hypocretins modulate arousal via actions across multiple terminal fields. Thus, alterations in hypocretin neurotransmission may contribute to altered sleep patterns observed during lactation. This study examined whether lactation is associated with alterations in the number of hypocretin neurons and in diurnal Fos-immunoreactivity within hypocretin neurons in female mice. Alterations in Fos-immunoreactivity were also examined within two hypocretin terminal regions; the medial preoptic area and the locus coeruleus. Fos-immunoreactivity was increased within hypocretin neurons and the medial preoptic area in lactating females. No differences were observed in the number of hypocretin neurons or in Fos-immunoreactivity within the locus coeruleus.

Delta and theta power spectra of night sleep EEG are higher in breast-feeding mothers than in non-pregnant women

The power spectra of night sleep EEGs of 12 breast-feeding 9-13 week postpartum mothers were analyzed and compared with those of 12 non-pregnant women. The power spectra in the delta and theta frequency range during NREM sleep for breast-feeding mothers were significantly higher than those for non-pregnant women. In addition, the all-night sleep patterns of the mothers were classified into two groups - interrupted sleep due to taking care of their infants and non-interrupted sleep - in order to observe the influence of partial sleep deprivation. The power spectra in the delta and theta frequency range were not significantly different between them. This result suggests that increased delta and theta power spectra during postpartum sleep do not result from partial sleep deprivation. The role of prolactin in breast-feeding mothers' sleep is also discussed.

Sleep EEG patterns and fatigue of middle-aged and older female family caregivers providing routine nighttime care for elderly persons at home

The sleep EEGs and fatigue of 9 female family caregivers (age M=65 yr.) and 9 female noncaregivers (age M=67 yr.) were measured during two successive nights at their houses. Perceived quality of sleep was measured by the Sleep Evaluation Questionnaire. Fatigue was measured by a self-rated questionnaire, the Perceived Symptoms of Fatigue, and by critical flicker fusion (CFF) frequency. The caregivers had a significantly higher percentage of Stage 1 and a lower percentage of Stage 2 during the 2nd cycle and a higher percentage of Stages 3+4 during the 3rd cycle than those of the noncaregivers. Caregivers had significantly higher percentages of EEG waves of 7-9 Hz in the 1st cycle and 6-9 Hz in the 2nd cycle and significantly lower percentages of 2-3 Hz in the 1st cycle than those of the noncaregivers. The caregivers reported a lower quality of sleep and higher perceived fatigue symptoms and also lower CFF frequency (increased physiological fatigue) than noncaregivers. The caregivers' sleep EEGs were associated with their higher sleep needs and fatigue.