Adverse Pregnancy Outcomes and Pharyngeal Flow Limitation during Sleep: Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be (nuMoM2b)

RATIONALE

Pharyngeal flow limitation during pregnancy may be a risk factor for adverse pregnancy outcomes but was previously challenging to quantify.

OBJECTIVE

To determine whether a novel objective measure of flow limitation identifies an increased risk of preeclampsia (primary outcome) and other adverse outcomes in a prospective cohort: Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be.

METHODS

Flow limitation severity scores (0%=fully obstructed, 100%=open airway)- quantified from breath-by-breath airflow shape-were obtained from home sleep tests during early (6-15 weeks) and mid (22-31 weeks) pregnancy. Multivariable logistic regression quantified associations between flow limitation (median overnight severity, both time-points averaged) and preeclampsia, adjusting for maternal age, body mass index (BMI), race, ethnicity, chronic hypertension, and flow limitation during wakefulness. Secondary outcomes were hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), and infant birthweight.

RESULTS

Of 1939 participants with flow limitation data at both time-points (age: 27.0±5.4 yr [mean±sd], BMI: 27.7±6.1 kg·m-2), 5.8% developed preeclampsia, 12.7% developed HDP, and 4.5% developed GDM. Greater flow limitation was associated with increased preeclampsia risk: adjusted Odds Ratio (OR) 2.49, 95% Confidence Interval [1.69, 3.69], per 2SD increase in severity. Findings persisted in women without sleep apnea (apnea-hypopnea index <5 events·hr-1). Flow limitation was associated with HDP (OR: 1.77 [1.33, 2.38]) and reduced infant birthweight (83.7 [31.8, 135.6] g), but not GDM.

CONCLUSIONS

Greater flow limitation is associated with increased risk of preeclampsia, HDP, and lower infant birthweight. Flow limitation may provide an early target for mitigating the consequences of sleep disordered breathing during pregnancy.

An approach for determining the reliability of manual and digital scoring of sleep stages

STUDY OBJECTIVES

Inter-scorer variability in sleep staging is largely due to equivocal epochs that contain features of more than one stage. We propose an approach that recognizes the existence of equivocal epochs and evaluates scorers accordingly.

METHODS

Epoch-by-epoch staging was performed on 70 polysomnograms by six qualified technologists and by a digital system (Michele Sleep Scoring [MSS]). Probability that epochs assigned the same stage by only two of the six technologists (minority score) resulted from random occurrence of two errors was calculated and found to be <5%, thereby indicating that the stage assigned is an acceptable variant for the epoch. Acceptable stages were identified in each epoch as stages assigned by at least two technologists. Percent agreement between each technologist and the other five technologists, acting as judges, was determined. Agreement was considered to exist if the stage assigned by the tested scorer was one of the acceptable stages for the epoch. Stage assigned by MSS was likewise considered in agreement if included in the acceptable stages made by the technologists.

RESULTS

Agreement of technologists tested against five qualified judges increased from 80.8% (range 70.5%-86.4% among technologists) when using the majority rule, to 96.1 (89.8%-98.5%) by the proposed approach. Agreement between unedited MSS and same judges was 90.0% and increased to 92.1% after brief editing.

CONCLUSIONS

Accounting for equivocal epochs provides a more accurate estimate of a scorer's (human or digital) competence in scoring sleep stages and reduces inter-scorer disagreements. The proposed approach can be implemented in sleep-scoring training and accreditation programs.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Association between sleep disordered breathing and neonatal outcomes in nulliparous individuals

BACKGROUND

To determine whether objectively measured Sleep-Disordered Breathing (SDB) during pregnancy is associated with an increased risk of adverse neonatal outcomes in a cohort of nulliparous individuals.

METHODS

Secondary analysis of the nuMom2b- sleep disordered breathing substudy was performed. Individuals underwent in-home sleep studies for SDB assessment in early- (6-15 weeks' gestation) and mid-pregnancy (22-31 weeks' gestation). SDB was defined as an apnea-hypopnea index ≥5 events/hour at either time point. Primary outcome was a composite outcome of respiratory distress syndrome, transient tachypnea of the newborn, or receipt of respiratory support, treated hyperbilirubinemia or hypoglycemia, large-for-gestational age (LGA), seizures treated with medications or confirmed by electroencephalography, confirmed sepsis, or neonatal death. Individuals were categorized into 1) early pregnancy SDB (6-15 weeks' gestation), 2) new onset mid-pregnancy SDB (22-31 weeks' gestation), and 3) no SDB. Log-binomial regression was used to calculate adjusted risk ratios (RR) and 95% confidence intervals (CI) representing the association. Adjustments were made for maternal age, chronic hypertension, pregestational diabetes, progesterone use and Body Mass Index (BMI), new onset mid-pregnancy SDB to establish if a relationship was still present.

RESULTS

Among 2,106 participants, 3% percent (n=75) had early pregnancy SDB and 5.7% (n=119) developed new onset mid-pregnancy SDB. The incidence of the primary outcome was higher in offspring of individuals with early- (29.3%) and new onset mid- pregnancy SDB (30.3%) compared to individuals with no SDB (17.8%). After adjustment for maternal age, chronic hypertension, pregestational diabetes, progesterone use and BMI, new onset mid-pregnancy SDB conferred increased risk (RR=1.42, 95% CI: 1.05, 1.92), where there was no longer statistically significant association between early pregnancy SDB and the primary outcome.

CONCLUSION

New Onset, Mid- pregnancy SDB is independently associated with neonatal morbidity.

Fetal heart rate responses to maternal sleep-disordered breathing

BACKGROUND

Maternal sleep-disordered breathing is associated with adverse pregnancy outcomes and is considered to be deleterious to the developing fetus. Maternal obesity potentiates sleep-disordered breathing, which, in turn, may contribute to the effect of maternal obesity on adverse fetal outcomes. However, only a few empirical studies have evaluated the contemporaneous effects of maternal sleep-disordered breathing events on fetal well-being. These events include apnea and hypopnea with accompanying desaturations in oxyhemoglobin.

OBJECTIVE

This study aimed to reconcile contradictory findings on the associations between maternal apnea or hypopnea events and clinical indicators of fetal compromise. It also sought to broaden the knowledge base by examining the fetal heart rate and heart rate variability before, during, and after episodes of maternal apnea or hypopnea. To accomplish this, we employed overnight polysomnography, the gold standard for ascertaining maternal sleep-disordered breathing, and synchronized it with continuous fetal electrocardiography.

STUDY DESIGN

A total of 84 pregnant women with obesity (body mass index >30 kg/m2) participated in laboratory-based polysomnography with digitized fetal electrocardiography recordings during or near 36 weeks of gestation. Sleep was recorded, on average, for 7 hours. Decelerations in fetal heart rate were identified. Fetal heart rate and heart rate variability were quantified before, during, and after each apnea or hypopnea event. Event-level intensity (desaturation magnitude, duration, and nadir O2 saturation level) and person-level characteristics based on the full overnight recording (apnea-hypopnea index, mean O2 saturation, and O2 saturation variability) were analyzed as potential moderators using linear mixed effects models.

RESULTS

A total of 2936 sleep-disordered breathing events were identified, distributed among all but 2 participants. On average, participants exhibited 8.7 episodes of apnea or hypopnea per hour (mean desaturation duration, 19.1 seconds; mean O2 saturation nadir, 86.6% per episode); nearly half (n=39) of the participants met the criteria for obstructive sleep apnea. Only 45 of 2936 apnea or hypopnea events were followed by decelerations (1.5%). Conversely, most (n=333, 88%) of the 378 observed decelerations, including the prolonged ones, did not follow an apnea or a hypopnea event. Maternal sleep-disordered breathing burden, body mass index, and fetal sex were unrelated to the number of decelerations. Fetal heart rate variability increased during events of maternal apnea or hypopnea but returned to initial levels soon thereafter. There was a dose-response association between the size of the increase in fetal heart rate variability and the maternal apnea-hypopnea index, event duration, and desaturation depth. Longer desaturations were associated with a decreased likelihood of the variability returning to baseline levels after the event. The mean fetal heart rate did not change during episodes of maternal apnea or hypopnea.

CONCLUSION

Episodes of maternal sleep apnea and hypopnea did not evoke decelerations in the fetal heart rate despite the predisposing risk factors that accompany maternal obesity. The significance of the modest transitory increase in fetal heart rate variability in response to apnea and hypopnea episodes is not clear but may reflect compensatory, delimited autonomic responses to momentarily adverse conditions. This study found no evidence that episodes of maternal sleep-disordered breathing pose an immediate threat, as reflected in fetal heart rate responses, to the near-term fetus.

Associations between evening shift work, irregular sleep timing, and gestational diabetes in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b)

Study Objectives

Shift work is a risk factor for cardiometabolic disease, possibly through effects on sleep-wake rhythms. We hypothesized that evening (afternoon and night combined) and irregular (irregular/on-call or rotating combined) shift work during pregnancy is associated with increased odds of preeclampsia, preterm birth, and gestational diabetes mellitus (GDM), mediated by irregular sleep timing.

Methods

The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b) is a prospective cohort study (n=10,038) designed to investigate risk factors for adverse pregnancy outcomes. Medical outcomes were determined with medical record abstraction and/or questionnaires; sleep midpoint was measured in a subset of participants with ≥5-day wrist actigraphy (ActiWatch). We estimated the association of evening and irregular shift work during pregnancy with preeclampsia, preterm birth, and GDM using logistic regression, adjusted for adversity (cumulative variable for poverty, education, health insurance, and partner status), smoking, self-reported race/ethnicity, and age. Finally, we explored whether the association between shiftwork and GDM was mediated by variability in sleep timing.

Results

Evening shift work is associated with approximately 75% increased odds of developing GDM (adjusted OR=1.75, 95% CI:1.12-2.66); we did not observe associations with irregular shifts, preterm birth, or preeclampsia after adjustment. Pregnant evening shift workers were found to have approximately 45 minutes greater variability in sleep timing compared to day workers (p&lt;0.005); sleep-timing variability explained 25% of the association between evening shift work and GDM in a mediation analysis.

Conclusions

Evening shift work was associated with GDM, and this relationship may be mediated by variability in sleep timing.

Sleep-disordered Breathing in Pregnancy and after Delivery: Associations with Cardiometabolic Health

Rationale: Knowledge gaps exist regarding health implications of sleep-disordered breathing (SDB) identified in pregnancy and/or after delivery. Objectives: To determine whether SDB in pregnancy and/or after delivery is associated with hypertension (HTN) and metabolic syndrome (MS). Methods: nuMoM2b-HHS (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be Heart Health Study) (N = 4,508) followed participants initially recruited during their first pregnancy. Participants returned for a visit 2-7 years after pregnancy. This study examined a subgroup who underwent SDB assessments during their first pregnancy (n = 1,964) and a repeat SDB assessment after delivery (n = 1,222). Two SDB definitions were considered: 1) apnea-hypopnea index (AHI) ⩾ 5 and 2) oxygen desaturation index (ODI) ⩾ 5. Associations between SDB and incident HTN and MS were evaluated with adjusted risk ratios (aRRs). Measurements and Main Results: The aRR for MS given an AHI ⩾ 5 during pregnancy was 1.44 (95% confidence interval [CI], 1.08-1.93), but no association with HTN was found. ODI ⩾ 5 in pregnancy was associated with both an increased risk for HTN (aRR, 2.02; 95% CI, 1.30-3.14) and MS (aRR, 1.53; 95% CI, 1.19-1.97). Participants with an AHI ⩾ 5 in pregnancy that persisted after delivery were at higher risk for both HTN (aRR, 3.77; 95% CI, 1.84-7.73) and MS (aRR, 2.46; 95% CI, 1.59-3.76). Similar associations were observed for persistent ODI ⩾ 5 after delivery. Conclusions: An AHI ⩾ 5 in pregnancy was associated with an increased risk of MS. An ODI ⩾ 5 in pregnancy was significantly associated with both HTN and MS. Participants with persistent elevations in AHI and ODI during pregnancy and at 2-7 years after delivery were at the highest risk for HTN and MS. Clinical trial registered with www.clinicaltrials.gov (NCT02231398).

Fetal neuromaturation in late gestation is affected by maternal sleep disordered breathing and sleep disruption in pregnant women with obesity

OBJECTIVE

Maternal sleep disordered breathing and sleep disruption have adverse effects on pregnancy outcomes through multiple potential pathophysiologic pathways. We hypothesize that disordered maternal sleep also adversely impacts the neuromaturation of the fetus.

METHODS

Participants in this prospective observational study included 102 obese pregnant women (pre-pregnancy body mass index [BMI] of 30 or higher) at 36 weeks of pregnancy. Fetal neuromaturation, defined through measures of fetal heart rate variability, motor activity, and motor-cardiac coupling, was quantified through digitized fetal actocardiography during an afternoon recording. Maternal sleep measures were collected overnight through polysomnography. Data analysis focused on multiple regression, controlling for maternal BMI, blood pressure, and diabetes.

RESULTS

Indicators of higher sleep disordered breathing were associated with delayed fetal neuromaturation and greater fetal motor activity. Less maternal sleep disruption (shorter rapid eye movement [REM] latency, more REM sleep, and/or fewer transitions) was associated with higher fetal heart rate variability and coupling-based neuromaturation.

CONCLUSION

Characteristics of disordered maternal sleep affect the developing fetal nervous system. It is unknown whether these results extend to populations that are not characterized by obesity. The influence of maternal sleep on the developing fetal nervous system has been understudied and may yield effects that persist beyond pregnancy.

Determinants of postpartum sleep duration and sleep efficiency in minority women

STUDY OBJECTIVES

To examine demographic, psychosocial, and behavioral determinants of postpartum sleep duration and sleep efficiency among a cohort of black and Latina women.

METHODS

Data were from 148 women (67% black, 32% Latina) at 5 months postpartum, recruited from an academic medical center in Philadelphia. Relevant demographic, psychosocial and behavioral predictors were assessed via questionnaire. Nocturnal sleep was objectively measured for 1 week using wrist actigraphy. Sleep duration was examined as a continuous variable and in categories (<7 versus ≥7 h per night); sleep efficiency was examined as a continuous variable. Independent multiple linear regression models were built to evaluate significant determinants of sleep.

RESULTS

Adjusted models revealed that breastfeeding, having a bedtime after midnight, and being employed were associated with shorter sleep duration (-25-33 min, all p < 0.05). Multiparity, being unmarried, being employed, breastfeeding, having a bedtime after midnight, bedsharing, and responding to infant awakenings by getting up immediately rather than waiting a few minutes to see if the infant fell back asleep, were all significant determinants of sleeping <7 h per night (OR varying: 2.29-4.59, all p < 0.05). Bedsharing was the only variable identified from the multiple regression model that associated with poorer sleep efficiency (-3.8%, p < 0.05).

CONCLUSIONS

Findings may inform interventions for improving postpartum sleep in socioeconomically disadvantaged, racial/ethnic minority postpartum women.

Fetal heart rate during maternal sleep

Despite prolonged and cumulative exposure during gestation, little is known about the fetal response to maternal sleep. Eighty-four pregnant women with obesity (based on pre-pregnancy BMI) participated in laboratory-based polysomnography (PSG) with continuous fetal electrocardiogram monitoring at 36 weeks gestation. Multilevel modeling revealed both correspondence and lack of it in maternal and fetal heart rate patterns. Fetal heart rate (fHR) and variability (fHRV), and maternal heart rate (mHR) and variability (mHRV), all declined during the night, with steeper rates of decline prior to 01:00. fHR declined upon maternal sleep onset but was not otherwise associated with maternal sleep stage; fHRV differed during maternal REM and NREM. There was frequent maternal waking after sleep onset (WASO) and fHRV and mHRV were elevated during these episodes. Cross-correlation analyses revealed little temporal coupling between maternal and fetal heart rate, except during WASO, suggesting that any observed associations in maternal and fetal heart rates during sleep are the result of other physiological processes. Implications of the maternal sleep context for the developing fetus are discussed, including the potential consequences of the typical sleep fragmentation that accompanies pregnancy.

Objectively assessed sleep-disordered breathing during pregnancy and infant birthweight

BACKGROUND

Sleep-disordered breathing (SDB) in pregnancy is associated with adverse maternal outcomes. The relationship between SDB and infant birthweight is unclear. This study's primary aim is to determine if objectively measured SDB in pregnancy is associated with infant birthweight.

METHODS

We measured SDB objectively in early (6-15 weeks' gestation) and mid (22-31 weeks' gestation) pregnancy in a large cohort of nulliparous women. SDB was defined as an Apnea-Hypopnea Index ≥5 and in secondary analyses we also examined measures of nocturnal hypoxemia. We used a modified Poisson regression approach to estimate relative risks (RR) of large-for-gestational-age (LGA: >90th percentile for gestational age) and small-for-gestational-age (SGA: <10th percentile for gestational age) birthweights.

RESULTS

The prevalence of early-pregnancy SDB was nearly 4%. The incidence of mid-pregnancy SDB was nearly 6.0%. The prevalence of LGA and SGA was 7.4% and 11.9%, respectively. Early-pregnancy SDB was associated with a higher risk of LGA in unadjusted models (RR 2.2, 95% CI 1.3-3.5) but not BMI-adjusted models (aRR 1.0, 95% CI 0.6-1.8). Mid-pregnancy SDB was not associated with SGA or LGA. Mid-pregnancy nocturnal hypoxemia (% of sleep time <90% oxygen saturation) and increasing nocturnal hypoxemia from early to mid-pregnancy were associated with a higher risk of LGA in BMI-adjusted models. SDB and nocturnal hypoxemia were not associated with SGA.

CONCLUSIONS

SDB in pregnancy was not associated with an increased risk of LGA or SGA birthweight, independent of BMI. Some measures nocturnal hypoxemia were associated with an increase in LGA risk, independent of BMI. ClinicalTrials.gov Registration number NCT02231398.

Associations between Diet and Sleep Duration in Different Menopausal Stages

This study aimed to determine which dietary factors were associated with habitual sleep duration in pre/peri- and post-menopausal women. Data from the 2007-2008 National Health and Nutrition Examination Survey were used (N = 1,783). Habitual sleep duration was categorized as very short (<5 h), short (5-6 h), normal (7-8 h), and long (≥9 h). Diet assessment was performed following validated procedures. In pre/peri-menopausal women (n = 1,116), controlling for the confounders, fewer number of foods, less intake of protein, carbohydrates, thiamin (B1), food folate, total choline, phosphorus, sodium, potassium, and selenium were significantly associated with a higher risk for very short sleep. Being on a low-salt diet was related to a lower risk for long sleep. In comparison, in post-menopausal women (n = 667), controlling for the confounders, more sugar intake, less intake of phosphorus and zinc were related to a higher risk for short sleep. There were novel associations between diet and sleep duration, particularly among pre/peri-menopausal women. Future research is needed to confirm those causal relationships.

A Screening Algorithm for Obstructive Sleep Apnea in Pregnancy

Rationale: Obstructive sleep apnea (OSA) is common in pregnancy and associated with maternal and fetal complications. Early detection of OSA may have important implications for maternal-fetal well-being. A screening tool combining several methods of assessment may better predict OSA among pregnant women compared with tools that rely solely on self-reported information.Objectives: To develop a screening tool combining subjective and objective measures to predict OSA in pregnant women.Methods: This study is a secondary analysis using data collected from a completed cohort of pregnant women (n = 121 during the first and n = 87 during the third trimester). Participants underwent full polysomnography and completed the Multivariable Apnea Prediction Questionnaire. The Obstructive Sleep Apnea/Hypopnea Syndrome Score and Facco apnea predictive model were obtained. Logistic regression analysis and area under the curve (AUC) were used to identify models predicting OSA risk.Results: Participants' mean age was 27.4 ± 7.0 years. The prevalence of OSA during the first and third trimester was 10.7% and 24.1%, respectively. The final model predicting OSA risk consisted of body mass index, age, and presence of tongue enlargement. During the first trimester, the AUC was 0.86 (95% confidence interval [CI], 0.76-0.96). During the third trimester, the AUC was 0.87 (95% CI, 0.77-0.96). When the first-trimester data were used to predict third-trimester OSA risk, the AUC was 0.87 (95% CI, 0.77-0.97). This model had high sensitivity and specificity when used during both trimesters. The negative posttest probabilities (probability of OSA given a negative test result) ranged from 0.03 to 0.07.Conclusions: A new model consisting of body mass index, age, and presence of tongue enlargement provided accurate screening of OSA in pregnant women, particularly African-Americans. This tool can be easily and rapidly administered in busy clinical practices without depending on patients' awareness of experiencing apnea symptoms.

Changing Faces of Obstructive Sleep Apnea: Treatment Effects by Cluster Designation in the Icelandic Sleep Apnea Cohort

Study Objectives

Distinct clinical phenotypes of obstructive sleep apnea (OSA) have been identified: Disturbed Sleep, Minimally Symptomatic, and Sleepy. Determining whether these phenotypes respond differently to standard treatment helps us to create a foundation for personalized therapies. We compared responses to positive airway pressure (PAP) therapy in these clinical OSA phenotypes.

Methods

The study sample included 706 patients from the Icelandic Sleep Apnea Cohort with moderate-to-severe OSA who were prescribed PAP. Linear and logistic mixed models were used to compare 2-year changes in demographics, comorbid diseases, and sleep-related health issues within and across OSA clinical phenotypes. Relationships between changes in symptoms and PAP adherence were also examined.

Results

Overall, effect sizes were moderate to large when comparing sleepiness, insomnia-related, and apneic symptom changes in the Sleepy group with changes in other two groups, especially those in the Minimally Symptomatic group. Within the Disturbed Sleep group, PAP users and nonusers demonstrated similar changes in insomnia-related symptoms. The Minimally Symptomatic group remained relatively asymptomatic, but reported significant decreases in daytime sleepiness and physical fatigue; PAP users generally had larger improvements. The Sleepy group had reductions in nearly all measured symptoms, including large reductions in drowsy driving; almost all of these improvements were greater among PAP users than nonusers.

Conclusions

OSA treatment response patterns differed by initial clinical phenotype and PAP adherence. Individuals with insomnia-related symptoms may require additional targeted therapy for these complaints. These findings underscore the need for a personalized approach to management that recognizes patients with a range of OSA presentations.

Association of Adverse Pregnancy Outcomes With Self-Reported Measures of Sleep Duration and Timing in Women Who Are Nulliparous

STUDY OBJECTIVES

To examine the relationship of self-reported sleep during pregnancy with adverse pregnancy outcomes. A secondary objective was to describe the concordance between self-reported and objectively assessed sleep during pregnancy.

METHODS

In this prospective cohort, women completed a survey of sleep patterns at 6 to 13 weeks' gestation (visit 1) and again at 22 to 29 weeks' gestation (visit 3). Additionally, at 16 to 21 weeks (visit 2), a subgroup completed a week-long sleep diary coincident with an actigraphy recording. Weekly averages of self-reported sleep duration and sleep midpoint were calculated. A priori, sleep duration < 7 hours was defined as "short," and sleep midpoint after 5:00 AM was defined as "late." The relationship of these sleep abnormalities with hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM) was determined.

RESULTS

Of the 10,038 women enrolled, sleep survey data were available for 7,524 women at visit 1 and 7,668 women at visit 3. A total of 752 women also provided ≥ 5 days of sleep diary data coincident with actigraphy at visit 2. We did not observe any consistent relationship between self-reported short sleep and HDP or GDM. There was an association between self-reported late sleep midpoint and GDM (visit 1 adjusted odds ratio 1.67, 95% confidence interval 1.17, 2.38; visit 2 adjusted odds ratio 1.73, 95% confidence interval 1.23, 2.43). At visit 2, 77.1% of participants had concordance between their diary and actigraphy for short sleep duration, whereas 94.3% were concordant for sleep midpoint.

CONCLUSIONS

Self-reported sleep midpoint, which is more accurate than self-reported sleep duration, is associated with the risk of GDM.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Title: Pregnancy as a Window to Future Cardiovascular Health: Adverse Pregnancy Outcomes as Predictors of Increased Risk Factors for Cardiovascular Disease, Identifier: NCT02231398, URL: https://clinicaltrials.gov/ct2/show/NCT02231398.

Changes in Sleep Characteristics and Breathing Parameters During Sleep in Early and Late Pregnancy

STUDY OBJECTIVES

Few studies have objectively evaluated sleep characteristics during pregnancy or investigated the relationship between altered spectral electroencephalogram (EEG) bands and sleep-disordered breathing (SDB). The study aimed to describe changes in sleep as measured by polysomnography (PSG) and spectral EEG bands during pregnancy and to examine the relationship between delta power in non-rapid eye movement (NREM) sleep and SDB.

METHODS

This is a secondary analysis of a prospective study. One hundred twenty-three women underwent full PSG in early pregnancy, and 97 repeated PSG in late pregnancy. Spectral analysis of the EEG in NREM sleep was performed. We used linear and logistic mixed-model regression to analyze the sleep measures and linear regression to explore the association between delta power and apnea-hypopnea index (AHI) changes during pregnancy.

RESULTS

In late pregnancy, women had shorter sleep duration, poorer sleep efficiency, more awakenings, more stage N2 sleep, less slow wave sleep, less REM sleep, higher AHI, and higher periodic limb movement index compared to early pregnancy. The percentage of stage N1 sleep, sleep latency, REM sleep latency, and arousal index frequency did not change. Regarding EEG-spectra, delta and theta powers decreased, but beta-2 power increased during pregnancy. In multivariable analyses, greater reduction of delta power was associated with larger increases in AHI (β [95% confidence interval] = -0.038 [-0.073, -0.002], P = .040). Estimates suggest that each one-unit increase in AHI reduces delta power by 4% in late pregnancy.

CONCLUSIONS

PSG-measured sleep characteristics change during pregnancy. Delta power decreases when the severity of SDB increases during pregnancy.

COMMENTARY

A commentary on this article appears in this issue on page 1095.

Predictors of sleep-disordered breathing in pregnancy

BACKGROUND

Sleep-disordered breathing (SDB) is common in pregnancy, but there are limited data on predictors.

OBJECTIVES

The objective of this study was to develop predictive models of sleep-disordered breathing during pregnancy.

STUDY DESIGN

Nulliparous women completed validated questionnaires to assess for symptoms related to snoring, fatigue, excessive daytime sleepiness, insomnia, and restless leg syndrome. The questionnaires included questions regarding the timing of sleep and sleep duration, work schedules (eg, shift work, night work), sleep positions, and previously diagnosed sleep disorders. Frequent snoring was defined as self-reported snoring ≥3 days per week. Participants underwent in-home portable sleep studies for sleep-disordered breathing assessment in early (6-15 weeks gestation) and mid pregnancy (22-31 weeks gestation). Sleep-disordered breathing was characterized by an apnea hypopnea index that included all apneas, plus hypopneas with ≥3% oxygen desaturation. For primary analyses, an apnea hypopnea index ≥5 events per hour was used to define sleep-disordered breathing. Odds ratios and 95% confidence intervals were calculated for predictor variables. Predictive ability of the logistic models was estimated with area under the receiver-operating-characteristic curves, along with sensitivities, specificities, and positive and negative predictive values and likelihood ratios.

RESULTS

Among 3705 women who were enrolled, data were available for 3264 and 2512 women in early and mid pregnancy, respectively. The corresponding prevalence of sleep-disordered breathing was 3.6% and 8.3%, respectively. At each time point in gestation, frequent snoring, chronic hypertension, greater maternal age, body mass index, neck circumference, and systolic blood pressure were associated most strongly with an increased risk of sleep-disordered breathing. Logistic regression models that included current age, body mass index, and frequent snoring predicted sleep-disordered breathing in early pregnancy, sleep-disordered breathing in mid pregnancy, and new onset sleep-disordered breathing in mid pregnancy with 10-fold cross-validated area under the receiver-operating-characteristic curves of 0.870, 0.838, and 0.809. We provide a supplement with expanded tables, integrated predictiveness, classification curves, and an predicted probability calculator.

CONCLUSION

Among nulliparous pregnant women, logistic regression models with just 3 variables (ie, age, body mass index, and frequent snoring) achieved good prediction of prevalent and incident sleep-disordered breathing. These results can help with screening for sleep-disordered breathing in the clinical setting and for future clinical treatment trials.

Reliability of the American Academy of Sleep Medicine Rules for Assessing Sleep Depth in Clinical Practice

STUDY OBJECTIVES

The American Academy of Sleep Medicine has published manuals for scoring polysomnograms that recommend time spent in non-rapid eye movement sleep stages (stage N1, N2, and N3 sleep) be reported. Given the well-established large interrater variability in scoring stage N1 and N3 sleep, we determined the range of time in stage N1 and N3 sleep scored by a large number of technologists when compared to reasonably estimated true values.

METHODS

Polysomnograms of 70 females were scored by 10 highly trained sleep technologists, two each from five different academic sleep laboratories. Range and confidence interval (CI = difference between the 5th and 95th percentiles) of the 10 times spent in stage N1 and N3 sleep assigned in each polysomnogram were determined. Average values of times spent in stage N1 and N3 sleep generated by the 10 technologists in each polysomnogram were considered representative of the true values for the individual polysomnogram. Accuracy of different technologists in estimating delta wave duration was determined by comparing their scores to digitally determined durations.

RESULTS

The CI range of the ten N1 scores was 4 to 39 percent of total sleep time (% TST) in different polysomnograms (mean CI ± standard deviation = 11.1 ± 7.1 % TST). Corresponding range for N3 was 1 to 28 % TST (14.4 ± 6.1 % TST). For stage N1 and N3 sleep, very low or very high values were reported for virtually all polysomnograms by different technologists. Technologists varied widely in their assignment of stage N3 sleep, scoring that stage when the digitally determined time of delta waves ranged from 3 to 17 seconds.

CONCLUSIONS

Manual scoring of non-rapid eye movement sleep stages is highly unreliable among highly trained, experienced technologists. Measures of sleep continuity and depth that are reliable and clinically relevant should be a focus of clinical research.

Sleep During Pregnancy: The nuMoM2b Pregnancy and Sleep Duration and Continuity Study

Study Objectives

To characterize sleep duration, timing and continuity measures in pregnancy and their association with key demographic variables.

Methods

Multisite prospective cohort study. Women enrolled in the nuMoM2b study (nulliparous women with a singleton gestation) were recruited at the second study visit (16-21 weeks of gestation) to participate in the Sleep Duration and Continuity substudy. Women <18 years of age or with pregestational diabetes or chronic hypertension were excluded from participation. Women wore a wrist activity monitor and completed a sleep log for 7 consecutive days. Time in bed, sleep duration, fragmentation index, sleep efficiency, wake after sleep onset, and sleep midpoint were averaged across valid primary sleep periods for each participant.

Results

Valid data were available from 782 women with mean age of 27.3 (5.5) years. Median sleep duration was 7.4 hours. Approximately 27.9% of women had a sleep duration of <7 hours; 2.6% had a sleep duration of >9 hours. In multivariable models including age, race/ethnicity, body mass index, insurance status, and recent smoking history, sleep duration was significantly associated with race/ethnicity and insurance status, while time in bed was only associated with insurance status. Sleep continuity measures and sleep midpoint were significantly associated with all covariates in the model, with the exception of age for fragmentation index and smoking for wake after sleep onset.

Conclusions

Our results demonstrate the relationship between sleep and important demographic characteristics during pregnancy.

Objectively measured short sleep duration and later sleep midpoint in pregnancy are associated with a higher risk of gestational diabetes

BACKGROUND

Experimental and epidemiologic data suggest that among nonpregnant adults, sleep duration may be an important risk factor for chronic disease. Although pregnant women commonly report poor sleep, few studies objectively evaluated the quality of sleep in pregnancy or explored the relationship between sleep disturbances and maternal and perinatal outcomes.

OBJECTIVE

Our objective was to examine the relationship between objectively assessed sleep duration, timing, and continuity (measured via wrist actigraphy) and maternal cardiovascular and metabolic morbidity specific to pregnancy.

STUDY DESIGN

This was a prospective cohort study of nulliparous women. Women were recruited between 16 0/7 and 21 6/7 weeks' gestation. They were asked to wear a wrist actigraphy monitor and complete a daily sleep log for a period of 7 consecutive days. The primary sleep exposure variables were the averages of the following over the total valid nights (minimum 5, maximum 7 nights): short sleep duration during the primary sleep period (<7 h/night), late sleep midpoint (midpoint between sleep onset and sleep offset >5 am), and top quartile of minutes of wake time after sleep onset and sleep fragmentation index. The primary outcomes of interest were a composite of hypertensive disorders of pregnancy (mild, severe, or superimposed preeclampsia; eclampsia; or antepartum gestational hypertension) and gestational diabetes mellitus. We used χ² tests to assess associations between sleep variables and categorical baseline characteristics. Crude odds ratios and 95% confidence intervals were estimated from univariate logistic regression models to characterize the magnitude of the relationship between sleep characteristics and hypertensive disorders of pregnancy and gestational diabetes. For associations significant in univariate analysis, multiple logistic regression was used to explore further the association of sleep characteristics with pregnancy outcomes.

RESULTS

In all, 901 eligible women consented to participate; 782 submitted valid actigraphy studies. Short sleep duration and a later sleep midpoint were associated with an increased risk of gestational diabetes (odds ratio, 2.24; 95% confidence interval, 1.11-4.53; and odds ratio, 2.58; 95% confidence interval, 1.24-5.36, respectively) but not of hypertensive disorders. A model with both sleep duration and sleep midpoint as well as their interaction term revealed that while there was no significant interaction between these exposures, the main effects of both short sleep duration and later sleep midpoint with gestational diabetes remained significant (adjusted odds ratio, 2.06; 95% confidence interval, 1.01-4.19; and adjusted odds ratio, 2.37; 95% confidence interval, 1.13-4.97, respectively). Additionally, after adjusting separately for age, body mass index, and race/ethnicity, both short sleep duration and later sleep midpoint remained associated with gestational diabetes. No associations were demonstrated between the sleep quality measures (wake after sleep onset, sleep fragmentation) and hypertensive disorders or gestational diabetes.

CONCLUSION

Our results demonstrate a relationship between short sleep duration and later sleep midpoint with gestational diabetes. Our data suggest independent contributions of these 2 sleep characteristics to the risk for gestational diabetes in nulliparous women.

Association Between Sleep-Disordered Breathing and Hypertensive Disorders of Pregnancy and Gestational Diabetes Mellitus

OBJECTIVE

To estimate whether sleep-disordered breathing during pregnancy is a risk factor for the development of hypertensive disorders of pregnancy and gestational diabetes mellitus (GDM).

METHODS

In this prospective cohort study, nulliparous women underwent in-home sleep-disordered breathing assessments in early (6-15 weeks of gestation) and midpregnancy (22-31 weeks of gestation). Participants and health care providers were blinded to the sleep test results. An apnea-hypopnea index of 5 or greater was used to define sleep-disordered breathing. Exposure-response relationships were examined, grouping participants into four apnea-hypopnea index groups: 0, greater than 0 to less than 5, 5 to less than 15, and 15 or greater. The study was powered to test the primary hypothesis that sleep-disordered breathing occurring in pregnancy is associated with an increased incidence of preeclampsia. Secondary outcomes were rates of hypertensive disorders of pregnancy, defined as preeclampsia and antepartum gestational hypertension, and GDM. Crude and adjusted odds ratios and 95% confidence intervals (CIs) were calculated from univariate and multivariate logistic regression models.

RESULTS

Three thousand seven hundred five women were enrolled. Apnea-hypopnea index data were available for 3,132 (84.5%) and 2,474 (66.8%) women in early and midpregnancy, respectively. The corresponding prevalence of sleep-disordered breathing was 3.6% and 8.3%. The prevalence of preeclampsia was 6.0%, hypertensive disorders of pregnancy 13.1%, and GDM 4.1%. In early and midpregnancy the adjusted odds ratios for preeclampsia when sleep-disordered breathing was present were 1.94 (95% CI 1.07-3.51) and 1.95 (95% CI 1.18-3.23), respectively; hypertensive disorders of pregnancy 1.46 (95% CI 0.91-2.32) and 1.73 (95% CI 1.19-2.52); and GDM 3.47 (95% CI 1.95-6.19) and 2.79 (95% CI 1.63-4.77). Increasing exposure-response relationships were observed between apnea-hypopnea index and both hypertensive disorders and GDM.

CONCLUSION

There is an independent association between sleep-disordered breathing and preeclampsia, hypertensive disorders of pregnancy, and GDM.

An Examination of Methodological Paradigms for Calculating Upper Airway Critical Pressures during Sleep

STUDY OBJECTIVES

The goal of this study was to examine different paradigms for determining critical closing pressures (Pcrit). Methods of determining Pcrit were compared, including direct observation of occluded (no flow) breaths versus inferring Pcrit from extrapolated data, and Pcrit generated by aggregating pressure-flow data from multiple runs versus Pcrit averaged across individual pressure-flow runs. The relationship between Pcrit and obstructive sleep apnea (OSA) was examined.

METHODS

A total of 351 participants with and without OSA underwent overnight polysomnography with pressure-flow measurements to determine Pcrit. A series of filters were applied to raw data to provide consistent, objective criteria for determining which data to include in Pcrit calculations. Observed Pcrit values were computed as the mean nasal pressure level at which a subject had at least two breaths with peak inspiratory flow < 50 mL/sec. Extrapolated Pcrit was calculated in two ways: (1) separately for each individual run and then averaged; and (2) using all valid data from individual runs combined into one plot.

RESULTS

Observed Pcrit was calculated in 67% to 69% of participants, a similar or higher proportion of study subjects compared to extrapolated Pcrit values using a ± 3 cm H2O filter. Although raw (unfiltered) extrapolated Pcrit measures were able to be calculated among a greater proportion of participants than filtered, extrapolated Pcrit values, and thus had fewer missing values, they had larger variability. Both extrapolated and observed Pcrit were higher among individuals with OSA compared to those without OSA.

CONCLUSIONS

Observed Pcrit provides a reliable descriptor of hypotonic upper airway collapsibility. Different methods for determining Pcrit were able to distinguish subjects with and without OSA.

Poor sleep in relation to natural menopause: a population-based 14-year follow-up of midlife women

OBJECTIVE

This study aims to estimate the prevalence and predictors of moderate/severe poor sleep in relation to the final menstrual period (FMP) in midlife women.

METHODS

Annual assessments were conducted in a population-based cohort of 255 women. All were premenopausal at cohort enrollment and reached natural menopause during the 16-year follow-up. The outcome measure was severity of poor sleep, as reported by participants in annual interviews for 16 years and as evaluated in relation to the FMP.

RESULTS

The annual prevalence of moderate/severe poor sleep largely ranged from about 28% to 35%, with no significant differences in any year relative to the FMP for the sample overall. When sleep status was stratified at premenopausal baseline, premenopausal sleep status strongly predicted poor sleep around the FMP. Women with moderate/severe poor sleep in premenopause were approximately 3.5 times more likely to have moderate/severe poor sleep around menopause than those with no poor sleep at baseline in adjusted analysis (odds ratio, 3.58; 95% CI, 2.50-5.11; P < 0.0001), whereas mild poor sleepers in premenopause were approximately 1.5 times more likely to have moderate/severe poor sleep around menopause (odds ratio, 1.57; 95% CI, 0.99-2.47; P = 0.053). There was no significant association between poor sleep and time relative to the FMP among women who had no poor sleep at premenopausal baseline. Hot flashes were significantly associated with poor sleep (odds ratio, 1.79; 95% CI, 1.44-2.21; P < 0.0001 in adjusted analysis) but had no interaction with baseline sleep severity (interaction P = 0.25), indicating that hot flashes contributed to poor sleep regardless of baseline sleep status.

CONCLUSIONS

Findings show a high prevalence of moderate/severe poor sleep in midlife women, with only a small "at-risk" subgroup having a significant increase in poor sleep in relation to the FMP. Sleep status at premenopausal baseline and concurrent hot flashes strongly and consistently predict poor sleep in the menopausal transition. Overall, poor sleep does not increase around the FMP and frequently occurs in the absence of hot flashes, indicating that sleep difficulties in the menopausal transition in generally healthy women are not simply associated with ovarian decline.

NuMoM2b Sleep-Disordered Breathing study: objectives and methods

OBJECTIVE

The objective of the Sleep Disordered Breathing substudy of the Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be (nuMoM2b) is to determine whether sleep disordered breathing during pregnancy is a risk factor for adverse pregnancy outcomes.

STUDY DESIGN

NuMoM2b is a prospective cohort study of 10,037 nulliparous women with singleton gestations that was conducted across 8 sites with a central Data Coordinating and Analysis Center. The Sleep Disordered Breathing substudy recruited 3702 women from the cohort to undergo objective, overnight in-home assessments of sleep disordered breathing. A standardized level 3 home sleep test was performed between 6(0)-15(0) weeks' gestation (visit 1) and again between 22(0)-31(0) weeks' gestation (visit 3). Scoring of tests was conducted by a central Sleep Reading Center. Participants and their health care providers were notified if test results met "urgent referral" criteria that were based on threshold levels of apnea hypopnea indices, oxygen saturation levels, or electrocardiogram abnormalities but were not notified of test results otherwise. The primary pregnancy outcomes to be analyzed in relation to maternal sleep disordered breathing are preeclampsia, gestational hypertension, gestational diabetes mellitus, fetal growth restriction, and preterm birth.

RESULTS

Objective data were obtained at visit 1 on 3261 women, which was 88.1% of the studies that were attempted and at visit 3 on 2511 women, which was 87.6% of the studies that were attempted. Basic characteristics of the substudy cohort are reported in this methods article.

CONCLUSION

The substudy was designed to address important questions regarding the relationship of sleep-disordered breathing on the risk of preeclampsia and other outcomes of relevance to maternal and child health.

The different clinical faces of obstructive sleep apnoea: a cluster analysis

Although commonly observed in clinical practice, the heterogeneity of obstructive sleep apnoea (OSA) clinical presentation has not been formally characterised. This study was the first to apply cluster analysis to identify subtypes of patients with OSA who experience distinct combinations of symptoms and comorbidities. An analysis of baseline data from the Icelandic Sleep Apnoea Cohort (822 patients with newly diagnosed moderate-to-severe OSA) was performed. Three distinct clusters were identified. They were classified as the "disturbed sleep group" (cluster 1), "minimally symptomatic group" (cluster 2) and "excessive daytime sleepiness group" (cluster 3), consisting of 32.7%, 24.7% and 42.6% of the entire cohort, respectively. The probabilities of having comorbid hypertension and cardiovascular disease were highest in cluster 2 but lowest in cluster 3. The clusters did not differ significantly in terms of sex, body mass index or apnoea-hypopnoea index. Patients with OSA have different patterns of clinical presentation, which need to be communicated to both the lay public and the professional community with the goal of facilitating care-seeking and early identification of OSA. Identifying distinct clinical profiles of OSA creates a foundation for offering more personalised therapies in the future.

The relationship and potential mechanistic pathways between sleep disturbances and maternal hyperglycemia

This paper reviews recent work investigating the influence of sleep disturbances on maternal hyperglycemia, particularly gestational diabetes mellitus (GDM). The incidence and prevalence of hyperglycemia are increasing worldwide, which is cause for concern because GDM and even mild hyperglycemia are associated with adverse pregnancy outcomes. A better understanding of sleep-related risk factors for maternal hyperglycemia is an important health matter. Evidence demonstrates associations between sleep disturbances, especially sleep-disordered breathing, and hyperglycemia, but causal effects and the underlying mechanisms linking these conditions have not been fully elucidated. Subjective sleep assessments show associations between sleep disturbances and maternal hyperglycemia. There are, however, few studies using objective measures to support these findings. Large prospective studies are required to examine causal relationships between sleep disturbances and maternal hyperglycemia. There is also a need for smaller mechanistic studies to understand the pathophysiology. Furthermore, interventional studies are required to address whether improvement of sleep parameters can prevent/decrease the risk of developing maternal hyperglycemia. Taken together, the data suggests that sleep disturbances during pregnancy are important to identify and manage in order to minimize maternal hyperglycemia and GDM, and improve maternal and fetal well-being.

Risk factors for sleep-disordered breathing in pregnancy

RATIONALE

Symptoms of sleep-disordered breathing (SDB) are common among pregnant women, and several studies link SDB symptoms with gestational hypertension and preeclampsia. However, few prospective studies objectively measuring SDB during pregnancy have been performed.

OBJECTIVES

We performed a prospective cohort study examining risk factors for third trimester SDB in pregnant women.

MEASUREMENTS AND METHODS

105 pregnant women from the Hospital of the University of Pennsylvania obstetrics practices completed first and third trimester overnight polysomnography studies. We examined whether the number of SDB events per hour of sleep increased during pregnancy. We performed unadjusted and multivariable logistic regression analyses to estimate the effects of usual and pregnancy-specific characteristics on development of third trimester obstructive sleep apnoea (OSA). In secondary analyses, we examined the relationship between objectively measured SDB, hypertensive disorders of pregnancy, and other adverse maternal-fetal outcomes.

MAIN RESULTS

Mean Apnoea-Hypopnoea Index increased from 2.07 (SD 3.01) events/h at baseline (first trimester) to 3.74 (SD 5.97) in the third trimester (p=0.009). 10.5% of women had OSA in the first trimester. By the third trimester, 26.7% of women had OSA. In multivariable analyses, first trimester body mass index (BMI) and maternal age were significantly associated with third trimester OSA.

CONCLUSIONS

Third trimester OSA is common. Risk factors for third trimester OSA among women without baseline SDB include higher baseline BMI and maternal age.

Objectively measured sleep duration and hyperglycemia in pregnancy

OBJECTIVE

Our primary purpose was to assess the impact of objectively measured nighttime sleep duration on gestational glucose tolerance. We additionally examined associations of objectively measured daytime sleep duration and nap frequency on maternal glycemic control.

METHODS

Sixty-three urban, low-income, pregnant women wore wrist actigraphs for an average of 6 full days in mid-pregnancy prior to screening for hyperglycemia using the 1-h oral glucose tolerance test (OGTT). Correlations of nighttime and daytime sleep durations with 1-h OGTT values were analyzed. Multivariable logistic regression was used to evaluate independent associations between sleep parameters and hyperglycemia, defined as 1-h OGTT values ≥130 mg/dL.

RESULTS

Mean nighttime sleep duration was 6.9±0.9 h which was inversely correlated with 1-h OGTT values (r=-0.28, P=.03). Shorter nighttime sleep was associated with hyperglycemia, even after controlling for age and body mass index (adjusted odds ratio [OR], 0.2 [95% confidence interval {CI}, 0.1-0.8]). There were no associations of daytime sleep duration and nap frequency with 1-h OGTT values or hyperglycemia.

CONCLUSIONS

Using objective measures of maternal sleep time, we found that women with shorter nighttime sleep durations had an increased risk for gestational hyperglycemia. Larger prospective studies are needed to confirm our negative daytime sleep findings.

Association between physical activity and insomnia symptoms in rural communities of southeastern Missouri, Tennessee, and Arkansas

PURPOSE

The purpose of this study is to examine whether physical activity is associated with less insomnia symptoms in the rural communities.

METHODS

This study used cross-sectional data collected from a 2005 telephone survey for evaluation of a community walking trails intervention to promote physical activity in rural communities including 6 communities in the Missouri Ozark region and 6 communities in Arkansas and Tennessee (n = 1,234). The exposure variable is self-reported regular current physical activity. The outcome includes symptoms of insomnia operationalized as having trouble falling asleep, staying asleep, and waking up too early nearly every day. Logistic regression was used to calculate prevalence odds ratios (PORs) and 95% confidence intervals (95% CI).

FINDINGS

The study sample includes mostly white (95%), married (62%), overweight/obese (61%) women with a high school degree and a mean age of 54. Fourteen percent of participants reported having insomnia symptoms. Self-report of currently being physically active regularly was associated with decreased odds of insomnia symptoms (adjusted POR: .37; 95% CI, 0.14-0.99) among participants with under or normal body weight, after controlling for age, gender, education level, marital status, and chronic diseases. There was also a negative linear correlation between the number of days and total minutes of vigorous physical activity and insomnia symptoms.

CONCLUSIONS

In these rural communities, we observed a significant relationship between regular physical activity and decreased insomnia symptoms.

Agreement in computer-assisted manual scoring of polysomnograms across sleep centers

STUDY OBJECTIVES

To determine intersite agreement in respiratory event scoring of polysomnograms (PSGs) using different hypopnea definitions.

DESIGN

Technical assessment.

SETTING

Five academic medical centers.

PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Seventy good-quality PSGs performed in middle-aged women were manually scored by two experienced technologists at each of the five sleep centers using the particular laboratory's own software system. Studies were scored once by each scorer using American Academy of Sleep Medicine (AASM) standards for scoring sleep stages, arousals, and apneas. Hypopneas were then scored using three different AASM criteria: recommended, alternate, and research (Chicago). Means of each PSG variable for the scorers at each site were used to calculate an across-site intraclass correlation coefficient (ICC). Average AHI across the 10 scorers was 7.4 ± 12.3 (standard deviation) events/h using recommended criteria (ICC 0.984; 95% confidence interval [CI] 0.977-0.990), 12.1 ± 13.3 events/h using alternate criteria (ICC 0.947; 95% CI 0.889-0.972), and 15.1 ± 13.9 events/h with Chicago criteria (ICC 0.800; 95% CI 0.768-0.828). ICC across sites was 0.870 (95% CI = 0.847-0.889) for total sleep time, 0.861 (95% CI 0.837-0.881) for number of obstructive apneas and 0.683 (95% CI 0.640-0.722) for number of central apneas. ICCs across sites for hypopneas were very good using recommended criteria (ICC 0.843; 95% CI 0.820-0.870) but decreased when alternate criteria (ICC 0.728; 95% CI 0.689-0.763) and Chicago criteria (ICC 0.535; 95% CI 0.485-0.583) were used.

CONCLUSION

Experienced scorers at different laboratories have very good agreement in hypopnea and AHI results when good-quality PSGs are scored using AASM-recommended criteria. Substantial degradation of reliability was observed for alternative definitions of hypopneas, particularly that proposed for research.

Performance of an automated polysomnography scoring system versus computer-assisted manual scoring

STUDY OBJECTIVES

Manual scoring of polysomnograms (PSG) is labor intensive and has considerable variance between scorers. Automation of scoring could reduce cost and improve reproducibility. The purpose of this study was to compare a new automated scoring system (YST-Limited, Winnipeg, Canada) with computer-assisted manual scoring.

DESIGN

Technical assessment.

SETTING

Five academic medical centers.

PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Seventy PSG files were selected at University of Pennsylvania (Penn) and distributed to five US academic sleep centers. Two blinded technologists from each center scored each file. Automatic scoring was performed at Penn by a YST Limited technician using a laptop containing the software. Variables examined were sleep stages, arousals, and apnea-hypopnea index (AHI) using three methods of identifying hypopneas. Automatic scores were not edited and were compared to the average scores of the 10 technologists. Intraclass correlation coefficient (ICC) was obtained for the 70 pairs and compared to across-sites ICCs for manually scored results. ICCs for automatic versus manual scoring were > 0.8 for total sleep time, stage N2, and nonrapid eye movement arousals and > 0.9 for AHI scored by primary and secondary American Academy of Sleep Medicine criteria. ICCs for other variables were not as high but were comparable to the across-site ICCs for manually scored results.

CONCLUSION

The automatic system yielded results that were similar to those obtained by experienced technologists. Very good ICCs were obtained for many primary PSG outcome measures. This automated scoring software, particularly if supplemented with manual editing, may increase laboratory efficiency and standardize PSG scoring results within and across sleep centers.

Screening for severe obstructive sleep apnea syndrome in hypertensive outpatients

The authors attempted to validate a 2-stage strategy to screen for severe obstructive sleep apnea syndrome (s-OSAS) among hypertensive outpatients, with polysomnography (PSG) as the gold standard. Using a prospective design, outpatients with hypertension were recruited from medical outpatient clinics. Interventions included (1) assessment of clinical data; (2) home sleep testing (HST); and (3) 12-channnel, in-laboratory PSG. The authors developed models using clinical or HST data alone (single-stage models) or clinical data in tandem with HST (2-stage models) to predict s-OSAS. For each model, area under receiver operating characteristic curves (AUCs), sensitivity, specificity, negative likelihood ratio, and negative post-test probability (NPTP) were computed. Models were then rank-ordered based on AUC values and NPTP. HST used alone had limited accuracy (AUC=0.727, NPTP=2.9%). However, models that used clinical data in tandem with HST were more accurate in identifying s-OSAS, with lower NPTP: (1) facial morphometrics (AUC=0.816, NPTP=0.6%); (2) neck circumference (AUC=0.803, NPTP=1.7%); and Multivariable Apnea Prediction Score (AUC=0.799, NPTP=1.5%) where sensitivity, specificity, and NPTP were evaluated at optimal thresholds. Therefore, HST combined with clinical data can be useful in identifying s-OSAS in hypertensive outpatients, without incurring greater cost and patient burden associated with in-laboratory PSG. These models were less useful in identifying obstructive sleep apnea syndrome of any severity.

Sleep-disordered breathing and daytime napping are associated with maternal hyperglycemia

OBJECTIVES

Sleep disturbances in pregnancy may impair glucose mechanism. This study aimed to examine associations of sleep-disordered breathing, sleep, and nap duration with 1-h glucose challenge test (GCT) levels in pregnant women after controlling for known risk factors for gestational diabetes.

METHODS

This is a case-control study of 104 pregnant women. All women underwent full polysomnography and a GCT and completed the multivariable apnea prediction and Pittsburgh Sleep Quality indexes. The primary outcome was maternal hyperglycemia measured by GCT. Bivariate and multivariable logistic regression analyses were performed.

RESULTS

Over 13 % subjects reported habitual snoring in the first trimester. Only 9.3 % women with normoglycemia (GCT < 135) were habitual snorers, whereas 45.5 % women with hyperglycemia (GCT ≥ 135) had habitual snoring (p < 0.001). Sleep-disordered breathing symptoms (loud snoring, snorting/gasping, and apneas) (odds ratio (OR) 2.85; 95 % confidence interval (CI) 1.50-5.41; p = 0.001) and total nap duration (OR 1.48; 95 % CI 0.96-2.28; p = 0.08) were associated with hyperglycemia. After adjusting for confounders, sleep-disordered breathing symptoms (OR 3.37; 95 % CI 1.44-8.32; p = 0.005) and nap duration (OR 1.64; 95 % CI 1.00-2.681.02; p = 0.05) continued to be associated with hyperglycemia. However, the primary exposure measure, the apnea/hypopnea index in the first trimester was not significantly associated with hyperglycemia (OR 1.03; 95 % CI 0.83-1.28; p = 0.77).

CONCLUSIONS

Sleep-disordered breathing symptoms and nap duration are associated with hyperglycemia. Sleep duration was not associated with hyperglycemia. Research is needed concerning whether women with sleep-disordered breathing and/or daytime napping are at risk for gestational diabetes.

The association of sleep duration and depressive symptoms in rural communities of Missouri, Tennessee, and Arkansas

PURPOSE

To determine the association between sleep duration and depressive symptoms in a rural setting.

METHODS

We conducted a cross-sectional study using data from Wave 3 of the Walk the Ozarks to Wellness Project including 12 rural communities in Missouri, Arkansas, and Tennessee (N = 1,204). Sleep duration was defined based on average weeknight and weekend hours per day: short (<7), optimal (7-8), and long (>8). The primary outcome was self-reported elevated depressive symptoms. Multivariable logistic regression was used to estimate adjusted prevalence odds ratios (aPOR) and 95% confidence intervals (95% CI).

FINDINGS

Elevated depressive symptoms were common in this rural population (17%). Depressive symptoms were more prevalent among subjects with short (26.1%) and long (24%) sleep duration compared to those with optimal (11.8%) sleep duration. After adjusting for age, gender, race, education, employment status, income, and BMI, short sleep duration was associated with increased odds of elevated depressive symptoms (aPOR = 2.12, 95% CI: 1.49, 3.01), compared to optimal sleep duration. Conversely, the association between long sleep duration and depressive symptoms was not statistically significant after covariate adjustment. Similar findings were observed when we excluded individuals with insomnia symptoms for analysis.

CONCLUSIONS

This study suggests that short sleep duration (<7 hours per night) and depressive symptoms are common among rural populations. Short sleep duration is positively associated with elevated depressive symptoms. The economic and health care burden of depression may be more overwhelming among rural populations, necessitating the need to target modifiable behaviors such as sleep habits to improve mental health.

Update on sleep and its disorders

Inadequate sleep and sleep disorders have important adverse consequences on multiple systems. This review covers three areas: (a) Genetic determinants of sleep disorders. Common gene variants with small effects have been identified for both restless legs syndrome and narcolepsy with cataplexy. Rare variants with large effects have been found in familial phase advance syndrome and in subjects with short sleep durations. (b) Obstructive sleep apnea (OSA). OSA is an oxidative stress disorder. Prospective cohort studies show an increased risk of cardiovascular events in patients with untreated severe OSA. (c) The impact of sleep disorders on obesity and diabetes. Inadequate sleep results in changes in insulin resistance and in hormone levels leading to increases in appetite. Hence, inadequate sleep is associated with development of obesity. OSA is also an independent risk factor for insulin resistance; treatment of OSA can improve insulin sensitivity.

Gender differences in obstructive sleep apnea and treatment response to continuous positive airway pressure

OBJECTIVES

Whether gender differences exist in clinical manifestations of obstructive sleep apnea (OSA) and whether women's responses to continuous positive airway pressure (CPAP) are similar to those of men are critical areas of exploration in sleep disordered breathing. This exploratory analysis addressed these questions by examining gender differences over a wide range of clinical outcomes at baseline and in response to CPAP in participants with severe OSA.

METHODS

Data from 152 men and 24 women who participated in a multicenter CPAP effectiveness study were analyzed. Gender differences in functional status (functional outcomes of sleep questionnaire, sickness impact profile), daytime sleepiness (epworth sleepiness scale, multiple sleep latency test), mood disturbance (profile of mood states), apnea symptoms (multivariable apnea prediction index), and neurobehavioral performance (psychomotor vigilance task) were examined. Treatment response was examined by the change in each outcome from baseline to 3 months after treatment.

RESULTS

Despite similar age, body mass index, and apnea-hypopnea index, women reported significantly lower functional status, more subjective daytime sleepiness, higher frequency of apnea symptoms, more mood disturbance, and poorer neurobehavioral performance compared to men at baseline. CPAP treatment significantly improved functional status and relieved symptoms for both genders. The magnitude of improvement in each clinical outcome did not vary by gender.

CONCLUSIONS

Women with OSA showed greater impairment in daytime functioning and symptoms than men. Both genders benefit from CPAP treatment. Adequately powered studies considering possible referral and response bias are necessary to examine gender differences in OSA clinical manifestations and response to CPAP treatment.

Sleep deprivation during pregnancy and maternal and fetal outcomes: is there a relationship?

Sleep duration in the population has been declining. Women occupy an increasingly prominent place in the work force without reducing most of their responsibilities at home. Consequently, sleep needs are often pushed to the bottom of women's daily priority list. Prior research has indicated that sleep deprivation is associated with higher levels of pro-inflammatory serum cytokines. This is important because higher plasma concentrations of pro-inflammatory serum cytokine levels are associated with postpartum depression and adverse birth outcomes such as preterm delivery. However, little research has directly examined how sleep deprivation may affect maternal and fetal outcomes. This review summarizes the existing data on the effect of sleep deprivation during pregnancy on maternal and fetal outcomes. We review supporting evidence for the hypotheses that sleep deprivation during pregnancy increases the risk of preterm delivery and postpartum depression, and that systemic inflammation is the causal mechanism in the association. Prior research on sleep in pregnancy has been limited by varying data collection methods, subjective self-reported sleep measures, small and non-representative samples, cross-sectional designs; descriptive or non-hypothesis driven studies. Future research with longitudinal study designs is needed to allow examination of the effect of sleep deprivation on adverse maternal and fetal outcomes.

Predictors of sleep quality in women in the menopausal transition

STUDY OBJECTIVES

To determine associations between menopausal status, reproductive hormone levels, menopausal symptoms, and poor sleep quality.

DESIGN

The present study examines subjective sleep quality over an 8-year period in participants in an ongoing longitudinal study of ovarian aging in a randomly identified cohort of African American and Caucasian women.

PARTICIPANTS

The Penn Ovarian Aging Study, a population-based cohort of 436 women from Philadelphia County who were 35 to 47 years of age and had regular menstrual cycles at enrollment.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

The primary outcome measure was the Sleep Quality factor score, derived from the St. Mary's Hospital Sleep Questionnaire, which was adapted for this population and collected at each assessment period over the 8-year follow-up. Associations between menopausal status, reproductive hormone levels, menopausal symptoms, sleep quality, age, and race were examined in multivariable linear mixed regression models for repeated measures. Menopausal status was not significantly associated with sleep quality (P = 0.12). In the adjusted model, independent predictors of sleep quality were hot flashes (P < 0.0001), Center for Epidemiological Studies Depression Scale scores (P < 0.0001) and levels of the reproductive hormone inhibin B (P = 0.05).

CONCLUSIONS

Sleep quality was predicted by hormone levels and symptoms that occur in the menopausal transition but did not worsen with advancing menopausal status alone. Lower inhibin B levels, hot flashes, and symptoms of depression were all strong and independent predictors of difficulty sleeping. Race was not a significant contributor to sleep quality. Together, the findings demonstrate that women who experience other perimenopausal symptoms are likely to experience sleep problems during the menopausal transition.

Symptoms associated with menopausal transition and reproductive hormones in midlife women

OBJECTIVE

To test the hypothesis that prevalence of women with menopausal symptoms of hot flushes; aches, joint pain, and stiffness; depressed mood; poor sleep; decreased libido; or vaginal dryness increases with progression through the menopausal transition.

METHODS

Women in the Penn Ovarian Aging Study were assessed longitudinally for 9 years. Data were obtained from structured interviews, a validated symptom questionnaire, menstrual bleeding dates and early follicular hormone measures (estradiol [E2], follicle-stimulating hormone [FSH], and inhibin b). Menopausal stages were based on menstrual bleeding patterns. Other risk factors included age, race, history of depression, current smoking, body mass index, and perceived stress. Generalized linear regression models for repeated measures were used to estimate associations among the variables with each symptom.

RESULTS

The prevalence of hot flushes; aches, joint pain, and stiffness; and depressed mood increased in the menopausal transition. Menopausal stage was associated with hot flushes (P<.001); aches joint pain, and stiffness (P<.001); and depressed mood (P=.002). Within-woman fluctuations of E2 were associated with hot flushes and aches. Poor sleep, decreased libido, and vaginal dryness were not associated with menopausal stages. There was 80% power to detect an absolute difference of 11% for libido and vaginal dryness and 17% for poor sleep in the prevalence of these symptoms in the late menopausal transition compared with premenopausal status.

CONCLUSION

The study highlights the role of menopausal stages for some symptoms of midlife women and indicates that stages in the transition to menopause are associated with hot flushes; aches, joint pain, and stiffness; and depressed mood. Fluctuations of E2, decreased levels of inhibin b, and increased FSH levels were associated with these symptoms.

LEVEL OF EVIDENCE

II.

Changes in Symptoms of Sleep-Disordered Breathing During Pregnancy

BACKGROUND

Although incident snoring is common in pregnant women and has been proposed as a potential risk factor for adverse maternal-fetal outcomes, the development of sleep-disordered breathing during pregnancy has not been prospectively described.

METHODS

Using the Apnea Symptom Score from the Multivariable Apnea Prediction Index and the Epworth Sleepiness Scale, we prospectively assessed symptoms of sleep-disordered breathing and daytime somnolence in 155 women to determine whether symptoms increased during pregnancy and the characteristics associated with increasing symptoms.

RESULTS

We found that sleep-disordered breathing symptoms (Apnea Symptom Score, 0.44 (SEM 0.58) vs 0.95 (0.09, P < .001) and the degree of daytime somnolence (Epworth Sleepiness Scale, 8.6 (0.3) vs 10.2 (0.4), P = .0003) increased significantly during pregnancy. Women with higher baseline body mass indexes and greater increases in neck circumference during pregnancy reported higher apnea symptom scores. Of the 155 subjects, 11.4% reported an increase in Apnea Symptom Score of 2 units or more, consistent with a clinically significant increase in symptoms; these women experienced a significantly greater increase in subjective sleepiness than other subjects (P = .03). Excessive daytime somnolence (Epworth Sleepiness Scale > 10) was prevalent throughout pregnancy (31.0%-45.5%).

CONCLUSIONS

Our data demonstrate that symptoms of sleep-disordered breathing increase during pregnancy and that more than 10% of our subjects may be at risk for developing sleep apnea during pregnancy. Excessive daytime somnolence was highly prevalent even early in pregnancy and became increasingly common as pregnancy progressed.

Sleep disorders during pregnancy

This paper reviews the topic of sleep disorders in pregnant women. We describe changes in sleep architecture and sleep pattern during pregnancy, discuss the impact of the physical and biochemical changes of pregnancy on sleep in pregnant women and examine whether maternal-fetal outcomes may be adversely affected in women with disordered sleep. The literature on common sleep disorders affecting pregnant women, including insomnia, sleep-disordered breathing and restless legs syndrome, is reviewed and recommendations are made for the management of these disorders during pregnancy.

Use of an implantable pleural catheter for trapped lung syndrome in patients with malignant pleural effusion

STUDY OBJECTIVES

We describe a series of patients with symptomatic, refractory malignant pleural effusion (MPE) and underlying trapped lung syndrome who underwent placement of a small-bore, flexible indwelling pleural catheter for home drainage of recurrent MPE.

DESIGN

The medical records of 11 consecutive patients who underwent pleural catheter placement for MPE with trapped lung syndrome were reviewed retrospectively.

SETTING

Patients were evaluated and followed up in the Pulmonary Outpatient Practice at the Hospital of the University of Pennsylvania.

PATIENTS

Nine men and two women with underlying malignancies including lung cancer, lymphoma, and mesothelioma underwent pleural catheter placement.

INTERVENTIONS

Thirteen pleural catheters were placed in 11 patients, all under local anesthesia. Patients received detailed instructions for drainage and catheter care. They were reevaluated weekly for the first 2 weeks, and then as clinically indicated. Patients typically performed pleural drainage at home up to 1,000 mL two or three times weekly.

MEASUREMENTS AND RESULTS

All patients reported symptomatic benefit, defined as improved dyspnea and exercise tolerance, except for one patient. In 10 patients, the pleural catheters remained in place until death, for 15 to 234 days. The mean length of placement was 115 days. One patient required revision after catheter occlusion. Other complications included catheter infection, localized skin breakdown, and possible cellulitis.

CONCLUSION

We have described a series of patients with MPE and trapped lung syndrome for whom placement of a permanent pleural catheter provided a convenient, effective alternative to the procedures currently in use. Our patients reported good symptomatic relief following catheter placement with few major complications.