Associations of snoring frequency and intensity in pregnancy with time-to-delivery

Common sleep disorders in pregnancy: a review

In this review, we provide a comprehensive overview of common sleep disorders during pregnancy, including their characterization, prevalence, risk factors, and possible contribution to maternal and fetal outcomes. We conducted a quasi-systematic literature search of the MEDLINE database and identified 744 studies from 1991 through 2021, inclusive, that met our inclusion criteria. We synthesized the existing literature on sleep disorders during pregnancy and highlighted controversies, research gaps, and needed clinical developments. Our review covers a range of sleep disorders, including insomnia, obstructive sleep apnea, restless legs syndrome, and circadian rhythm disorders. We discuss the prevalence of these disorders in pregnancy and their potential impact on maternal and fetal health outcomes. We also explore the relationship between sleep disorders, pre-pregnancy comorbidities such as obesity, and pregnancy-related conditions such as gestational diabetes mellitus and preeclampsia. In addition to summarizing the existing literature on sleep disorders during pregnancy, we also highlight opportunities for further research in this area. We suggest that future studies should strive to employ validated and objective measurement tools for sleep disorders and prioritize utilization of longitudinal methods with participant follow-up through postpartum, mid-life, menopause, and beyond. We also put forward investigation into the impact of circadian rhythm disruption on reproductive physiology and early pregnancy outcomes as an area of important work. Overall, our review provides valuable insights on sleep and reproduction and into common sleep disorders during pregnancy and their potential impact on maternal and fetal health outcomes.

Racial/ethnic disparities in subjective sleep duration, sleep quality, and sleep disturbances during pregnancy: an ECHO study

In the United States, racial/ethnic minoritized groups experience worse sleep than non-Hispanic Whites (nHW), but less is known about pregnant people. This is a key consideration since poor sleep during pregnancy is common and associated with increased risk of adverse perinatal outcomes. This study reports the prevalence of subjective sleep measures in a multi-racial/ethnic pregnant population from the Environmental influences on Child Health Outcomes (ECHO) program. Participants' self-reported race and ethnicity were grouped into: nHW, non-Hispanic Black/African American (nHB/AA), Hispanic, non-Hispanic Asian (nHA). Analyses examined trimester-specific (first (T1), second (T2), third (T3)) nocturnal sleep duration, quality, and disturbances (Pittsburgh Sleep Quality Index and ECHO maternal sleep health questionnaire). Linear or multinomial regressions estimated the associations between race/ethnicity and each sleep domain by trimester, controlling for body mass index and age, with nHW as reference group. We repeated analyses within maternal education strata. nHB/AA participants reported shorter sleep duration (T2: β = -0.55 [-0.80,-0.31]; T3: β = -0.65 [-0.99,-0.31]) and more sleep disturbances (T2: β = 1.92 [1.09,2.75]; T3: β = 1.41 [0.09,2.74]). Hispanic participants reported longer sleep duration (T1: β = 0.22 [0.00004,0.44]; T2: β = 0.61 [0.47,0.76]; T3: β = 0.46 [0.22,0.70]), better sleep quality (Reference group: Very good. Fairly good T1: OR = 0.48 [0.32,0.73], T2: OR = 0.36 [0.26,0.48], T3: OR = 0.31 [0.18,0.52]. Fairly bad T1: OR = 0.27 [0.16,0.44], T2: OR = 0.46 [0.31, 0.67], T3: OR = 0.31 [0.17,0.55]), and fewer sleep disturbances (T2: β = -0.5 [-1.0,-0.12]; T3: β = -1.21 [-2.07,-0.35]). Differences persisted within the high-SES subsample. Given the stark racial/ethnic disparities in perinatal outcomes and their associations with sleep health, further research is warranted to investigate the determinants of these disparities.

Maternal habitual snoring and blood pressure trajectories in pregnancy

STUDY OBJECTIVES

Habitual snoring has been associated with hypertensive disorders of pregnancy. However, exactly when blood pressure (BP) trajectories diverge between pregnant women with and without habitual snoring is unknown. Moreover, the potentially differential impact of chronic vs pregnancy-onset habitual snoring on maternal BP trajectories during pregnancy has not been examined. This study compared patterns of BP across pregnancy in 3 groups of women: those with chronic habitual snoring, those with pregnancy-onset habitual snoring, and nonhabitual snoring "controls."

METHODS

In a cohort study of 1,305 pregnant women from a large medical center, participants were asked about habitual snoring (≥ 3 nights/week) and whether their symptoms began prior to or during pregnancy. Demographic, health, and BP data throughout pregnancy were abstracted from medical charts. Linear mixed models were used to examine associations between habitual snoring-onset and pregnancy BP trajectories.

RESULTS

A third of women reported snoring prior to pregnancy (chronic snoring) and an additional 23% reported pregnancy-onset snoring. Mean maternal age (SD) was 29.5 (5.6), 30 (6), and 30.5 (5.7) years in controls, chronic, and pregnancy-onset snoring, respectively. Overall, women with pregnancy-onset snoring had higher mean systolic BP and diastolic BP compared to those with chronic habitual snoring or nonhabitual snoring. In gestational week-specific comparisons with controls, systolic BP became significantly higher around 18 weeks' gestation among women with pregnancy-onset snoring and in the third trimester among women with chronic snoring. These differences became detectable at 1 mm Hg and increased thereafter, reaching 3 mm Hg-BP difference at 40 weeks' gestation in women with pregnancy-onset snoring relative to controls. Pairwise mean differences in diastolic BP were significant only among women with pregnancy-onset snoring relative to controls, after 15 weeks' gestation.

CONCLUSIONS

Pregnancy-onset and chronic maternal snoring are associated with higher BPs beginning in the second and third trimester, respectively. Pregnancy BP trajectories could identify critical windows for enhanced BP surveillance; the divergent BP trajectories suggest that the 2 groups of women with habitual snoring in pregnancy may need to be considered separately when gestational time intervals are evaluated for increased BP monitoring.

CITATION

Dunietz GL, Hao W, Shedden K, et al. Maternal habitual snoring and blood pressure trajectories in pregnancy. J Clin Sleep Med. 2022;18(1):31-38.

Burden of sleep disturbance in non-Hispanic Black pregnant women

STUDY OBJECTIVES

Non-Hispanic Black pregnant women disproportionately experience poor perinatal outcomes compared to other racial/ethnic groups. Sleep disruption has emerged as a risk factor for adverse pregnancy outcomes but there are limited data in minority pregnant women. We examined the prevalence of habitual snoring and its timing of onset with several key sleep-wake disturbances and their associations with perinatal outcomes in a cohort of non-Hispanic Black pregnant women.

METHODS

Third trimester non-Hispanic Black pregnant women were recruited from a large, academic medical center and screened for habitual snoring - and its timing relative to pregnancy - sleep quality, symptoms of insomnia, excessive daytime sleepiness, as well as daytime function. Clinical diagnoses of hypertensive disorders of pregnancy were obtained along with delivery outcomes.

RESULTS

In 235 women the vast majority (80%) reported three or more sleep-wake disturbances, and almost half had at least five disturbances. Sixteen percent endorsed pre-pregnancy snoring and 20% pregnancy-onset snoring. Women with pregnancy-onset snoring had significantly increased odds of poor sleep quality aOR 8.2, trouble staying asleep aOR 3.6, waking up too early aOR 2.7, excessive daytime sleepiness aOR 2.3, and poor daytime function aOR 8.7 but no relationship with perinatal outcomes. In contrast, pre-pregnancy snoring was related to chronic hypertension, pre-term delivery and fetal growth restriction; aOR 2.6, aOR 2.8, and aOR 5.1 respectively.

CONCLUSIONS

Sleep-wake disturbances confer a significant burden to pregnant non-Hispanic Black women, an infrequently studied yet disproportionately affected population. Contributions of maternal sleep to racial disparities in perinatal health should be a priority for public health research.

Sleep position and breathing in late pregnancy and perinatal outcomes

STUDY OBJECTIVES

Body position during sleep has been related to breathing in adults with obstructive sleep apnea (OSA). While sleep-disordered breathing is common, little information is available on the relation between sleep position and maternal breathing in pregnancy. We examined associations between the supine position, maternal breathing, and perinatal outcomes.

METHODS

Women with a singleton, uncomplicated pregnancy were recruited and underwent an ambulatory overnight sleep study between 33 to 36 weeks using the Watch-PAT device. Their medical records were also reviewed.

RESULTS

A total of 148 pregnant women were recruited (mean age: 33 ± 4 years; mean body mass index: 27.6 ± 4.0 kg/m²). They spent approximately one-half of their sleeping time in a supine position. The group's mean apnea-hypopnea index (AHI) was 3.6 events/h in the supine position and 2.9, 2.6, and 2.1 events/h for the prone, right, and left positions, respectively. Median AHI and oxygen desaturation index were higher and SpO₂ nadir was lower in the supine versus nonsupine position (P < .0001, P < .0001, and P = .006, respectively). Peripheral oxygen saturation nadir was associated with the percentage of time spent sleeping in the supine position (P = .02). No correlations were found between supine sleep position and perinatal outcomes. There were no differences in the distributions of body positions between women with and those without OSA.

CONCLUSIONS

Women in the third trimester of pregnancy with or without OSA spent large proportions of sleeping time in a supine position. Supine position was associated with more respiratory events and more and deeper oxygen desaturation events. They were not associated with perinatal outcomes.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Fetal Outcome of Sleep Disordered Breathing During Pregnancy; URL: https://clinicaltrials.gov/ct2/show/NCT00931099; Identifier: NCT00931099.

Snoring and depression symptoms in pregnant women

OBJECTIVE

Pregnant patients are vulnerable to both depression and sleep-disordered breathing, and both convey risks for maternal and fetal outcomes. Previous research has indicated that sleep-disordered breathing is associated with depression, but further information related to the risk of depression based on timing of onset of snoring is needed.

DESIGN

When presenting to clinic for their initial prenatal visit, pregnant patients completed a packet of questionnaires, which included measures related to depression (Edinburgh Postnatal Depression Scale) and snoring. Habitual snoring was defined as snoring 3 or more nights per week.

RESULTS

In total, 1367 women were included and 34.1% reported habitual snoring, either chronic (24.4%) or pregnancy-onset (9.8%), with increased frequency of pregnancy-onset habitual snoring in later stages of pregnancy. Unadjusted analyses suggested increased odds of depressive symptoms in chronic and pregnancy-onset habitual snoring groups relative to nonsnorers (odds ratio [OR]: 2.01, 95% confidence interval [CI]: 1.39, 2.92, P < .01; OR: 2.50, 95% CI: 1.54, 4.07, P < .01, respectively). These findings were maintained after adjusting for maternal age, marital status, gestational age, and parity (chronic habitual snoring OR: 1.69, 95% CI: 1.14, 2.53, P < .01; pregnancy-onset habitual snoring OR: 2.79, 95% CI: 1.35, 5.78, P < .01).

CONCLUSIONS

Maternal snoring may be a risk factor for prenatal depressive symptoms. Pregnancy-onset habitual snoring confers additional risk for depression compared to not snoring during pregnancy.

Sleep disturbances during pregnancy and adverse maternal and fetal outcomes: A systematic review and meta-analysis

Sleep disturbances are highly prevalent in pregnancy and are frequently overlooked as a potential cause of significant morbidity. The association between sleep disturbances and pregnancy outcomes remains largely controversial and needs to be clarified to guide management. To evaluate the association between sleep disturbances and maternal complications and adverse fetal outcomes, we performed a systematic search of PubMed, Embase and Web of Science for English-language articles published from inception to March 6, 2020, including observational studies of pregnant women with and without sleep disturbances assessing the risk of obstetric complications in the antenatal, intrapartum or postnatal period, and neonatal complications. Data extraction was completed independently by two reviewers. We utilized the Newcastle-Ottawa Scales to assess the methodological quality of included studies and random-effect models to pool the associations. A total of 120 studies with 58,123,250 pregnant women were included. Sleep disturbances were assessed, including poor sleep quality, extreme sleep duration, insomnia symptoms, restless legs syndrome, subjective sleep-disordered breathing and diagnosed obstructive sleep apnea. Significant associations were found between sleep disturbances in pregnancy and a variety of maternal complications and adverse fetal outcomes. Overall sleep disturbances were significantly associated with pre-eclampsia (odds ratio = 2.80, 95% confidence interval: 2.38-3.30), gestational hypertension (1.74, 1.54-1.97), gestational diabetes mellitus (1.59, 1.45-1.76), cesarean section (1.47, 1.31-1.64), preterm birth (1.38, 1.26-1.51), large for gestational age (1.40, 1.11-1.77), and stillbirth (1.25, 1.08-1.45), but not small for gestational age (1.03, 0.92-1.16), or low birth weight (1.27, 0.98-1.64). Sleep disturbances were related to higher morbidities in pregnant women who are 30 y or older and overweight before pregnancy. The findings indicate that sleep disturbances, which are easily ignored and treatable for both pregnant women and clinical services, deserve more attention from health care providers during prenatal counseling and health care services.

Associations of plasma hypocretin-1 with metabolic and reproductive health: Two systematic reviews of clinical studies

The hypocretin system consists of two peptides hypocretin-1 and hypocretin-2 (HCRT1 and HCRT2). Hypocretin-containing neurons are located in the posterior and lateral hypothalamus, and have widespread projections throughout the brain and spinal cord. In addition to its presence in the cerebrospinal fluid (CSF), peripheral HCRT1 has been detected in plasma. Robust experimental evidence demonstrates functions of hypothalamic-originated HCRT1 in regulation of multiple biological systems related to sleep-wake states, energy homeostasis and endocrine function. In contrast, HCRT1 studies with human participants are limited by the necessarily invasive assessment of CSF HCRT1 to patients with underlying morbidity. Regulation by HCRT1 of energy homeostasis and reproduction in animals suggests similar regulation in humans and prompts these two systematic reviews. These reviews translate prior experimental findings from animal studies to humans and examine associations between HCRT1 and: 1) metabolic risk factors; 2) reproductive function in men, women and children. A total of 21 studies and six studies met the inclusion criteria for the two searches, respectively. Research question, study design, study population, assessments of HCRT1, reproductive, cardiometabolic data and main findings were extracted. Associations between HCRT1, metabolic and reproductive function are inconsistent. Limitations of studies and future research directions are outlined.

Sleep-disordered breathing does not impact maternal outcomes in women with hypertensive disorders of pregnancy

Objective

Sleep-disordered breathing (SDB) is characterised by intermittent hypoxemia, sympathetic activation and widespread endothelial dysfunction, sharing pathophysiologic features with the hypertensive disorders of pregnancy. We sought to determine whether coexisting SDB would adversely impact the outcomes of women with gestational hypertension (GH) and preeclampsia (PE), and healthy matched controls.

Study design

Women diagnosed with GH or PE along with BMI- and gestation-matched normotensive controls underwent polysomnography in late pregnancy to establish the presence or absence of SDB (RDI ≥ 5). Clinical outcomes of hypertensive disease severity were compared between groups, and venous blood samples were taken in the third trimester and at delivery to examine for any impact of SDB on the anti-angiogenic markers of PE.

Results

Data was available for 17 women with PE, 24 women with GH and 44 controls. SDB was diagnosed in 41% of the PE group, 63% of the GH group and 39% of the control group. Women with PE and co-existing SDB did not have worse outcomes in terms of gestation at diagnosis of PE (SDB = 29.1 (25.9, 32.1) weeks vs. no SDB = 32.0 (29.0, 33.9), p = n.s.) and days between diagnosis of PE and delivery (SDB = 20.0 (4.0, 35.0) days vs. no SDB = 10.5 (9.0, 14.0), p = n.s.). There were also no differences in severity of hypertension, antihypertensive treatment and biochemical, haematological and anti-angiogenic markers of PE between SDB and no SDB groups. Similar results were observed among women with GH. Healthy control women with SDB were no more likely to develop a hypertensive disorder of pregnancy in the later stages of pregnancy (SDB = 5.9% vs. no SDB = 7.4%, p = n.s.). Increasing the threshold for diagnosis of SDB to RDI ≥ 15 did not unmask a worse prognosis.

Conclusion

The presence of SDB during pregnancy did not worsen the disease course of GH or PE, and was not associated with high blood pressure or anti-angiogenic markers of hypertensive disease amongst healthy pregnant women. Given the numerous reports of the relationship between SDB and diagnosis of hypertensive disorders of pregnancy, it appears more work is required to distinguish causal, versus confounding, pathways.

Associations between symptoms of sleep-disordered breathing and maternal sleep patterns with late stillbirth: Findings from an individual participant data meta-analysis

BACKGROUND AND OBJECTIVES

Sleep-disordered breathing (SDB) affects up to one third of women during late pregnancy and is associated with adverse pregnancy outcomes, including hypertension, diabetes, impaired fetal growth, and preterm birth. However, it is unclear if SDB is associated with late stillbirth (≥28 weeks' gestation). The aim of this study was to investigate the relationship between self-reported symptoms of SDB and late stillbirth.

METHODS

Data were obtained from five case-control studies (cases 851, controls 2257) from New Zealand (2 studies), Australia, the United Kingdom, and an international study. This was a secondary analysis of an individual participant data meta-analysis that investigated maternal going-to-sleep position and late stillbirth, with a one-stage approach stratified by study and site. Inclusion criteria: singleton, non-anomalous pregnancy, ≥28 weeks' gestation. Sleep data ('any' snoring, habitual snoring ≥3 nights per week, the Berlin Questionnaire [BQ], sleep quality, sleep duration, restless sleep, daytime sleepiness, and daytime naps) were collected by self-report for the month before stillbirth. Multivariable analysis adjusted for known major risk factors for stillbirth, including maternal age, body mass index (BMI kg/m2), ethnicity, parity, education, marital status, pre-existing hypertension and diabetes, smoking, recreational drug use, baby birthweight centile, fetal movement, supine going-to-sleep position, getting up to use the toilet, measures of SDB and maternal sleep patterns significant in univariable analysis (habitual snoring, the BQ, sleep duration, restless sleep, and daytime naps). Registration number: PROSPERO, CRD42017047703.

RESULTS

In the last month, a positive BQ (adjusted odds ratio [aOR] 1.44, 95% confidence interval [CI] 1.02-2.04), sleep duration >9 hours (aOR 1.82, 95% CI 1.14-2.90), daily daytime naps (aOR 1.52, 95% CI 1.02-2.28) and restless sleep greater than average (aOR 0.62, 95% CI 0.44-0.88) were independently related to the odds of late stillbirth. 'Any' snoring, habitual snoring, sleep quality, daytime sleepiness, and a positive BQ excluding the BMI criterion, were not associated.

CONCLUSION

A positive BQ, long sleep duration >9 hours, and daily daytime naps last month were associated with increased odds of late stillbirth, while sleep that is more restless than average was associated with reduced odds. Pregnant women may be reassured that the commonly reported restless sleep of late pregnancy may be physiological and associated with a reduced risk of late stillbirth.