A systematic review and quantitative assessment of sleep-disordered breathing during pregnancy and perinatal outcomes

Application of portable sleep monitoring devices in pregnancy: a comprehensive review

Objective.The physiological, hormonal and biomechanical changes during pregnancy may trigger sleep disordered breathing (SDB) in pregnant women. Pregnancy-related sleep disorders may associate with adverse fetal and maternal outcomes including gestational diabetes, preeclampsia, preterm birth and gestational hypertension. Most of the screening and diagnostic studies that explore SDB during pregnancy were based on questionnaires which are inherently limited in providing definitive conclusions. The current gold standard in diagnostics is overnight polysomnography (PSG) involving the comprehensive measurements of physiological changes during sleep. However, applying the overnight laboratory PSG on pregnant women is not practical due to a number of challenges such as patient inconvenience, unnatural sleep dynamics, and expenses due to highly trained personnel and technology. Parallel to the progress in wearable sensors and portable electronics, home sleep monitoring devices became indispensable tools to record the sleep signals of pregnant women at her own sleep environment. This article reviews the application of portable sleep monitoring devices in pregnancy with particular emphasis on estimating the perinatal outcomes.Approach.The advantages and disadvantages of home based sleep monitoring systems compared to subjective sleep questionnaires and overnight PSG for pregnant women were evaluated.Main Results.An overview on the efficiency of the application of home sleep monitoring in terms of accuracy and specificity were presented for particular fetal and maternal outcomes.Significance.Based on our review, more homogenous and comparable research is needed to produce conclusive results with home based sleep monitoring systems to study the epidemiology of SDB in pregnancy and its impact on maternal and neonatal health.

Sleep quality during pregnancy and fetal growth: A prospective cohort study

The aim of this study is to investigate the association between sleep quality during pregnancy and fetal growth. Pregnant women and their fetuses at 16-20 gestational weeks in Nantong Maternal and Child Health Hospital were recruited. Women were classified as having "good sleep quality" (Pittsburgh Sleep Quality Index score ≤ 5) and "poor sleep quality" (Pittsburgh Sleep Quality Index score > 5) according to the Pittsburgh Sleep Quality Index scores. The fetal growth was evaluated by three ultrasonographic examinations, birth weight and birth length. We used general linear model and multiple linear regression models to estimate the associations. A total of 386 pairs of mother and infant were included in the data analysis. After adjusting for gestational weight gain, anxiety and depression, fetuses in the good sleep quality group had greater abdominal circumference (p = 0.039 for 28-31+6 weeks gestation, p = 0.012 for 37-40+6 weeks gestation) and femur length (p = 0.014 for 28-31+6 weeks gestation, p = 0.041for 37-40+6 weeks gestation) at 28-31+6 weeks gestation and 37-40+6 weeks gestation, and increased femur length (p = 0.007) at 28-31+6 weeks gestation. Birth weights (p = 0.018) were positively associated with sleep quality. Poor sleep quality was associated with poor intrauterine physical development, decreased abdominal circumference and femur length, and lower birth weight after adjusting for confounding factors. Attention to the fetal growth of pregnant women with poor sleep quality has the potential to decrease the risk of adverse fetal outcomes.

Obstructive Sleep Apnea in Pregnancy: A Comprehensive Review of Maternal and Fetal Implications

Obstructive sleep apnea (OSA) is a prevalent yet underdiagnosed condition in pregnancy, associated with various maternal and fetal complications. This review synthesizes the current evidence on the epidemiology, pathophysiology, and neurological consequences of OSA in pregnancy, along with the potential management strategies. Articles were sourced from the PubMed, EMBASE, and Cochrane databases until 2023. Our comprehensive review highlights that the incidence of OSA increases during pregnancy due to physiological changes such as weight gain and hormonal fluctuations. OSA in pregnancy is linked with gestational hypertension, pre-eclampsia, gestational diabetes, and potential adverse fetal outcomes such as intrauterine growth restriction and preterm birth. Continuous positive airway pressure (CPAP) therapy remains the most effective management strategy for pregnant women with OSA. However, adherence to CPAP therapy is often suboptimal. This comprehensive review underscores the importance of the early recognition, timely diagnosis, and effective management of OSA in pregnancy to improve both maternal and fetal outcomes. Future research should focus on enhancing screening strategies and improving adherence to CPAP therapy in this population.

Association between Sleep Disordered Breathing and Neonatal Outcomes in Nulliparous Individuals

OBJECTIVE

Our objective was 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.

STUDY DESIGN

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/h at either time point. The 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, 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 (CIs) representing the association.

RESULTS

Among 2,106 participants, 3% (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 the offspring of individuals with early (29.3%) and new onset mid-pregnancy SDB (30.3%) compared with individuals with no SDB (17.8%). After adjustment for maternal age, chronic hypertension, pregestational diabetes, and body mass index, new onset mid-pregnancy SDB conferred increased risk (RR = 1.43, 95% CI: 1.05, 1.94), 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.

KEY POINTS

· SDB is a common condition impacting pregnancy with known maternal risks.. · Objectively defined SDB in pregnancy was associated with a composite of adverse neonatal outcomes.. · New onset SDB in mid pregnancy conferred statistically significant increased risk..

The effect of maternal sleep quality in late pregnancy on prenatal, birth and early postnatal outcomes

This cross-sectional study investigated the effect of maternal sleep quality in late pregnancy on prenatal, birth and early postnatal outcomes. The research was conducted in three parts with women at 28 or more weeks of gestation. In the first part, pregnant women admitted for delivery were evaluated in terms of eligibility criteria. Pregnant women in the latent phase of labour completed the Prenatal Questionnaire. In the second part, labour follow-up was performed. The researchers completed the Birth Follow-up Questionnaire based on observations and hospital birth records. In the third part, mothers were interviewed between the 12th and 24th hour of postnatal. Participants filled out the Postnatal Questionnaire, the Childbirth Experience Questionnaire, and the Pittsburgh Sleep Quality Index (n = 385). The data were analysed using the chi-square independence test, Fisher test, independent samples t-test, effect sizes, and binary logistic regression analysis. Participants had a mean maternal sleep quality score of 4.00 ± 1.38. They slept for 7.53 ± 0.92 hr on average. One-third of the participants were poor sleepers (32.2%). Employed participants were 71.6% less likely to have poor maternal sleep quality than their non-employed counterparts (odds ratio = 0.29, 95% confidence interval: 0.13-0.62; p = 0.002). The odds of poor maternal sleep quality increased by 13.7% when maternal weight gain during pregnancy increased by 1 kg (odds ratio = 1.14, 95% confidence interval: 1.03-1.26; p = 0.014). Increased maternal sleep quality positively affected the birth process (p < 0.05). Healthcare professionals should routinely screen the maternal sleep quality of pregnant women and increase their sleep hygiene.

Vision-based detection and quantification of maternal sleeping position in the third trimester of pregnancy in the home setting-Building the dataset and model

In 2021, the National Guideline Alliance for the Royal College of Obstetricians and Gynaecologists reviewed the body of evidence, including two meta-analyses, implicating supine sleeping position as a risk factor for growth restriction and stillbirth. While they concluded that pregnant people should be advised to avoid going to sleep on their back after 28 weeks' gestation, their main critique of the evidence was that, to date, all studies were retrospective and sleeping position was not objectively measured. As such, the Alliance noted that it would not be possible to prospectively study the associations between sleeping position and adverse pregnancy outcomes. Our aim was to demonstrate the feasibility of building a vision-based model for automated and accurate detection and quantification of sleeping position throughout the third trimester-a model with the eventual goal to be developed further and used by researchers as a tool to enable them to either confirm or disprove the aforementioned associations. We completed a Canada-wide, cross-sectional study in 24 participants in the third trimester. Infrared videos of eleven simulated sleeping positions unique to pregnancy and a sitting position both with and without bed sheets covering the body were prospectively collected. We extracted 152,618 images from 48 videos, semi-randomly down-sampled and annotated 5,970 of them, and fed them into a deep learning algorithm, which trained and validated six models via six-fold cross-validation. The performance of the models was evaluated using an unseen testing set. The models detected the twelve positions, with and without bed sheets covering the body, achieving an average precision of 0.72 and 0.83, respectively, and an average recall ("sensitivity") of 0.67 and 0.76, respectively. For the supine class with and without bed sheets covering the body, the models achieved an average precision of 0.61 and 0.75, respectively, and an average recall of 0.74 and 0.81, respectively.

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.

Society of Anesthesia and Sleep Medicine and the Society for Obstetric Anesthesia and Perinatology Consensus Guideline on the Screening, Diagnosis, and Treatment of Obstructive Sleep Apnea in Pregnancy

The Society of Anesthesia and Sleep Medicine and the Society for Obstetric Anesthesia and Perinatology tasked an expert group to review existing evidence and to generate recommendations on the screening, diagnosis, and treatment of patients with obstructive sleep apnea during pregnancy. These recommendations are based on a systematic review of the available scientific evidence and expert opinion when scientific evidence is lacking. This guideline may not be appropriate for all clinical situations and patients, and physicians must decide whether these recommendations are appropriate for their patients on an individual basis. We recognize that not all pregnant people may identify as women. However, data on non-cisgendered pregnant patients are lacking, and many published studies use gender-binary terms; therefore, depending on the study referenced, we may refer to pregnant individuals as women. This guideline may inform the creation of clinical protocols by individual institutions that consider the unique considerations of their patient populations and the available resources.

Obstructive Sleep Apnea Among Gravidas With Chronic Hypertension Compared to Matched Controls: A Prospective Cohort Study

BACKGROUND

Previous studies of obstructive sleep apnea (OSA) risk in gravidas with chronic hypertension (cHTN) did not control for obesity as a risk factor for OSA. We therefore performed this study to evaluate whether OSA is more prevalent among gravidas with cHTN compared to normotensive gravidas matched for body mass index (BMI) and gestational age (primary outcome). We also assessed whether OSA is more severe when comorbid with cHTN in pregnancy (secondary outcome).

METHODS

This was a single-center, prospective cohort study. Adult gravidas at 10-20 weeks of gestation, with and without cHTN, were enrolled and BMI matched. All subjects answered OSA screening questionnaires and underwent a home sleep test when they were between 10 and 20 weeks of gestation. Pregnancy outcomes were followed for all subjects. We performed univariable and multivariable logistic regression to model the relationship between cHTN status and OSA.

RESULTS

A total of 100 pregnant subjects (50 with cHTN and 50 normotensive) completed a home sleep test of 2 hours or more. There were no differences in demographic variables between the 2 groups, except that gravidas with cHTN were significantly older than normotensive subjects (mean ± standard deviation [SD] 34 ± 4 vs 30 ± 6 years; P < .001). OSA was more prevalent (64% vs 38%; P = .009; odds ratio [95% confidence interval (CI)] 2.90 [1.30-6.65]; P = .01) and more severe in gravidas with cHTN (moderate or severe OSA 59% vs 21%; P = .009). After controlling for age, we found no overall association between cHTN on OSA risk (adjusted odds ratio [95% CI] 2.22 [0.92-5.40]; P = .076). However, among gravidas older than 25 years of age, cHTN was associated with higher odds of OSA (adjusted odds ratio [95% CI], 2.64 [1.06-6.71], P = .038).

CONCLUSIONS

cHTN and age are important risk factors for OSA in gravidas. Gravidas with cHTN should be screened for OSA in early pregnancy. Future studies may validate screening tools that include cHTN and age, and investigate the role of OSA therapy in blood pressure control.

Longitudinal Sleep Study in Pregnancy: Cohort Profile and Prevalence and Risk Factors for Sleep Symptoms in the First Trimester

Sleep disorders could influence pregnancy outcomes but evidence for longitudinal associations is scarce. We established a prospective cohort of women to determine incident sleep issues and their adverse health outcomes during pregnancy and beyond, and present here the baseline cohort profile. Antenatal women in gestational weeks 8-12 were recruited (n = 535) and followed-up in each trimester and at 5-6 weeks postpartum (no attrition). Sleep symptoms and disorders were measured using STOP-Bang and Berlin questionnaires and Pittsburgh Sleep Quality Index. Incident health outcomes were extracted from clinical records. At the time of recruitment, habitual snoring was present in 13.8% of participants; "excessive sleepiness during the day" (EDS) in 42.8%; short (<7 h) sleep duration in 46.4%; "having trouble sleeping" in 15.3%; and "poor subjective sleep quality" in 8.6%. Habitual snoring was strongly associated with irregular menstrual periods for one year preceding pregnancy (p = 0.014) and higher BMI (p < 0.001). Higher age was associated with less "trouble sleeping" (OR 0.9, p = 0.033) and longer sleep duration was associated with better "subjective sleep quality" (OR 0.8, p = 0.005). Sleep issues were highly prevalent at baseline and associated with age, irregular menstruation, and obesity. This cohort will provide a robust platform to investigate incident sleep disorders during pregnancy and their effects on adverse pregnancy outcomes and long-term health of women and their offspring.

The role of melatonin in pregnancies complicated by placental insufficiency: A systematic review

Placental insufficiency affects about 10% of pregnancies and can lead to pre-eclampsia, fetal growth restriction, and preterm birth. Despite significant advances in early prediction and prevention of preterm pre-eclampsia with aspirin, the effects of prophylaxis on fetal growth restriction are less certain, and the rates of late-onset pre-eclampsia are not influenced by aspirin treatment. Pregnancies complicated by placental insufficiency are characterized by increased oxidative stress, and recent studies suggest that melatonin has antioxidant properties and contributes to maintaining placental homeostasis. We aimed to systematically review the available literature about melatonin in pregnancies complicated by placental insufficiency, specifically preeclampsia and fetal growth restriction, exploring three different aspects: 1) maternal melatonin levels; 2) expression and activity of melatonin placental receptors; 3) effects of maternal melatonin administration. PubMed (Medline) and Scopus were searched until December 2020. Identified studies were screened and assessed independently by two authors. Data were extracted and compiled in qualitative evidence synthesis. The circadian pattern of melatonin secretion seems to be altered in pregnancies complicated by placental insufficiency reflected by lower production of melatonin, with consequent lower systemic and placental concentrations and lower expression of melatonin receptors, thus reducing the local release of the indole and its autocrine function. Small intervention studies also suggest that treatment is safe and may lead to prolongation of pregnancy and better outcomes, but double-blind, randomized placebo-controlled trials are lacking.

Cardio-Obstetrics: the Next Frontier in Cardiovascular Disease Prevention

Purpose of Review

Internationally, cardiovascular disease (CVD) is the leading cause of death in women. With risk factors for CVD continuing to rise, early identification and management of chronic diseases such as hypertension, diabetes, and obstructive sleep apnea is necessary for prevention. Pregnancy is a natural stress test for women with risk factors who may be predisposed to CVD and offers a unique opportunity to not only recognize disease but also implement effective and long-lasting strategies for prevention.

Recent Findings

Prevention begins before pregnancy, as preconception screening, counseling, and optimization of chronic diseases can improve maternal and fetal outcomes. Throughout pregnancy, women should maintain close follow-up, continued reevaluation of risk factors, with counseling when necessary. Continued healthcare engagement during the “fourth trimester,” 3 months following delivery, allows clinicians to continue monitoring the evolution of chronic diseases, encourage ongoing lifestyle counseling, and connect women with primary care and appropriate specialists if needed. Unfortunately, this postpartum period represents a major care gap, as a significant proportion of most women do not attend their scheduled visits. Social determinants of health including decreased access to care and economic instability lead to increased risk factors throughout pregnancy but particularly play a role in poor compliance with postpartum follow-up. The use of telemedicine clinics and remote monitoring may prove to be effective interventions, bridging the gap between physicians and patients and improving follow-up for at-risk women.

Summary

While many clinicians are beginning to understand the impact of CVD on women, screening and prevention strategies are not often implemented until much later in life. Pregnancy creates an opportunity to begin engaging women in cardiovascular protective strategies before the development of the disease.

Gestational Intermittent Hypoxia Induces Sex-Specific Impairment in Endothelial Mechanisms and Sex Steroid Hormone Levels in Male Rat Offspring

Obstructive sleep apnea (OSA) is highly prevalent during gestation and is linked with adverse fetal outcomes. We examined whether gestational intermittent hypoxia (GIH), the main feature of OSA, leads to sex-specific alterations in cardiovascular function and vascular mechanisms in the offspring. Pregnant rats exposed to intermittent hypoxia or ambient air from gestation days 10 to 21 and their offspring were used for the study. GIH exposure did not affect water and food intake in dams. Compared to controls, the male and female offspring born to GIH dams were smaller in weight by 14% and 12%, respectively, and exhibited catch-up growth. Cardiac function was not affected in either GIH males or females. At 12 weeks of age, blood pressure was increased in GIH males, but not GIH females, compared to their control counterparts. While mesenteric arterial contractile responses to phenylephrine and endothelin were unaffected in GIH males and females, relaxation response to acetylcholine was reduced in GIH males but not GIH females. Relaxation to sodium nitroprusside was unaffected in both GIH males and females. Total eNOS expression was not affected, but phospho(Ser1177)-eNOS levels were decreased in GIH males. eNOS expression and its phosphorylation status were unaffected in GIH females. Serum testosterone and estradiol levels were higher in GIH males but were unaltered in GIH females. Together, these findings suggest that GIH leads to a sex-specific increase in blood pressure in adult male offspring with blunted endothelium-mediated relaxation, decreased eNOS activity, and elevated sex steroid hormone levels.

A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy

OBJECTIVE

In pregnancy melatonin regulates circadian rhythms, induce sleep, and has a neuroprotective positive effect on fetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus, we investigated the effect of blocking blue light on the melatonin profile.

METHODS

A randomized controlled trial (n=30 blue-blocking glasses vs. n=30 control glasses with partial blue-blocking effect) including healthy nulliparous pregnant women in the beginning of the third trimester. Salivary melatonin and subjective sleep were measured before and after two weeks of intervention/control condition. Saliva was sampled at 30-min intervals from 3 h before normal bedtime. Melatonin onset was set at 4.0 pg/ml.

RESULTS

Due to missing data melatonin onset was estimated for 47 participants. At posttreatment, melatonin onset advanced by 28 min in the blue-blocking group compared with the control condition (p=.019). Melatonin levels were significantly higher, favoring the blue-blocking glass condition, at clock time 20:00, 21:00 and 22:00 h, and for sample number 3 and 4. The phase angle (time interval) between melatonin onset and sleep bedtime and sleep onset time increased within the blue blocking group (+45 min and +41 min, respectively), but did not reach statistical significance compared to control condition (+13 min and +26 min, respectively).

CONCLUSION

Blocking blue light in the evening had a positive effect on the circadian system with an earlier onset and rise of melatonin levels in healthy nulliparous pregnant women. This demonstrated the effectiveness and feasibility of a simple non-pharmacological chronobiological intervention during pregnancy.

Obstructive sleep apnea in pregnant women

The prevalence of OSA in the low-risk obstetric population is thought to be low; best estimates have been extrapolated from the one available large prospective study and likely range between 3–8%.1 OSA prevalence in high-risk pregnant women such as those with obesity and chronic hypertension is significantly higher as extrapolated from several smaller prospective studies which have reported a prevalence as high as 37% in obese women.2 –6 Despite the high prevalence of OSA in high-risk pregnant women, it remains underdiagnosed due to several factors.

An emerging body of literature suggests that OSA may also have serious implications for the health of mothers and fetuses during and beyond pregnancy, but there is still no data to determine if OSA treatment mitigates these adverse outcomes. In this review, we will examine this body of literature from the perspective of the anesthesiologist: the association between pregnancy and the development or worsening of OSA; OSA as it relates to adverse maternal and fetal outcomes; antepartum and screening considerations for OSA in pregnant women; and recommendations regarding the peripartum management of OSA.

A feature of maternal sleep apnea during gestation causes autism-relevant neuronal and behavioral phenotypes in offspring

Mounting epidemiologic and scientific evidence indicates that many psychiatric disorders originate from a complex interplay between genetics and early life experiences, particularly in the womb. Despite decades of research, our understanding of the precise prenatal and perinatal experiences that increase susceptibility to neurodevelopmental disorders remains incomplete. Sleep apnea (SA) is increasingly common during pregnancy and is characterized by recurrent partial or complete cessations in breathing during sleep. SA causes pathological drops in blood oxygen levels (intermittent hypoxia, IH), often hundreds of times each night. Although SA is known to cause adverse pregnancy and neonatal outcomes, the long-term consequences of maternal SA during pregnancy on brain-based behavioral outcomes and associated neuronal functioning in the offspring remain unknown. We developed a rat model of maternal SA during pregnancy by exposing dams to IH, a hallmark feature of SA, during gestational days 10 to 21 and investigated the consequences on the offspring's forebrain synaptic structure, synaptic function, and behavioral phenotypes across multiples stages of development. Our findings represent a rare example of prenatal factors causing sexually dimorphic behavioral phenotypes associated with excessive (rather than reduced) synapse numbers and implicate hyperactivity of the mammalian target of rapamycin (mTOR) pathway in contributing to the behavioral aberrations. These findings have implications for neuropsychiatric disorders typified by superfluous synapse maintenance that are believed to result, at least in part, from largely unknown insults to the maternal environment.

A randomized controlled trial on the effects of blue-blocking glasses compared to partial blue-blockers on sleep outcomes in the third trimester of pregnancy

OBJECTIVE

Sleep disturbances are common in pregnancy. Blocking blue light has been shown to improve sleep and may be a suitable intervention for sleep problems during pregnancy. The present study investigated the effects of blue light blocking in the evening and during nocturnal awakenings among pregnant women on primary sleep outcomes in terms of total sleep time, sleep efficiency and mid-point of sleep.

METHODS

In a double-blind randomized controlled trial, 60 healthy nulliparous pregnant women in the beginning of the third trimester were included. They were randomized, using a random number generator, either to a blue-blocking glass intervention (n = 30) or to a control glass condition constituting partial blue-blocking effect (n = 30). Baseline data were recorded for one week and outcomes were recorded in the last of two intervention/control weeks. Sleep was measured by actigraphy, sleep diaries, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale.

RESULTS

The results on the primary outcomes showed no significant mean difference between the groups at posttreatment, neither when assessed with sleep diary; total sleep time (difference = .78[min], 95%CI = -19.7, 21.3), midpoint of sleep (difference = -8.9[min], 95%CI = -23.7, 5.9), sleep efficiency (difference = -.06[%], 95%CI = -1.9, 1.8) and daytime functioning (difference = -.05[score points], 95%CI = -.33, .22), nor by actigraphy; total sleep time (difference = 13.0[min], 95%CI = -9.5, 35.5), midpoint of sleep (difference = 2.1[min], 95%CI = -11.6, 15.8) and sleep efficiency (difference = 1.7[%], 95%CI = -.4, 3.7). On the secondary outcomes, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale the blue-blocking glasses no statistically significant difference between the groups were found. Transient side-effects were reported in both groups (n = 3).

CONCLUSIONS

The use of blue-blocking glasses compared to partially blue-blocking glasses in a group of healthy pregnant participants did not show statistically significant effects on sleep outcomes. Research on the effects of blue-blocking glasses for pregnant women with sleep-problems or circadian disturbances is warranted.

TRIAL REGISTRATION

The trial is registered at ClinicalTrials.gov (NCT03114072).

Sleep quality and health among pregnant smokers

STUDY OBJECTIVES

We aimed to examine 1) sleep quality trends of pregnant smokers and 2) their associations with health outcomes.

METHODS

A secondary analysis of 88 participants from the University at Buffalo Pregnancy and Smoking Cessation Study (non-randomized clinical study) was performed. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI) (higher scores, worse quality) and sleep duration was self-reported repeatedly during pregnancy at pre-intervention, post-intervention, and end-of-pregnancy visits. Participants were divided into 3 groups (until pre-intervention, until post-intervention, until end-of-pregnancy). Maternal outcomes included gestational weight gain (GWG) and smoking cessation. Infant outcomes included birth weight, gestational age, and APGAR score.

RESULTS

There was a significant increase (P= 0.046) in PSQI score from post-intervention (mean, 5.5 [SD, 2.6]) to end-of-pregnancy (6.6 [SD, 2.8]). Mean GWG was significantly lower for participants with poor sleep quality than those with good sleep quality (19.0 kg [SD, 21.3] vs. 36.1 kg [SD, 22.8]; P=0.008). Newborns with poor maternal sleep quality had a significantly lower mean 5-minute APGAR score (8.1 [SD, 1.3] vs. 9.0 [SD, 0.0]; P=0.021) than newborns with good maternal sleep quality. Pre-intervention sleep quality was not associated with smoking cessation, birth weight, or gestational age. Smoking cessation was almost half as prevalent in participants with insufficient sleep (<7 hours/night) vs. sufficient sleep duration (47.4% vs. 92.3%, P=0.011).

CONCLUSIONS

Sleep quality worsened towards the end-of-pregnancy among smokers. Poor sleep might negatively influence GWG and APGAR score. Insufficient pre-intervention sleep might negatively influence smoking cessation.

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.

Maternal and fetal outcomes in pregnancies with obstructive sleep apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is linked to many health comorbidities. We aimed to ascertain if OSA correlates with a rise in poor obstetrical outcomes.

METHODS

Employing the United States' Healthcare Cost and Utilization Project - National Inpatient Sample, we performed our retrospective cohort study including all women who delivered between 2006 and 2015. ICD-9 codes were used to characterize women as having a diagnosis of OSA. Temporal trends in pregnancies with OSA were studied, baseline features were evaluated among gravidities in the presence and absence of OSA, and multivariate logistic regression analysis was utilized in assessing consequences of OSA on patient and newborn outcomes.

RESULTS

Of a total 7,907,139 deliveries, 3,115 belonged to patients suffering from OSA, resulting in a prevalence of 39 per 100,000 deliveries. Rates rose from 10.14 to 78.12 per 100,000 deliveries during the study interval (p<0.0001). Patients diagnosed with OSA were at higher risk of having pregnancies with preeclampsia, OR 2.2 (95% CI 2.0-2.4), eclampsia, 4.1 (2.4-7.0), chorioamnionitis, 1.4 (1.2-1.8), postpartum hemorrhage, 1.4 (1.2-1.7), venous thromboembolisms, 2.7 (2.1-3.4), and to deliver by caesarean section, 2.1 (1.9-2.3). Cardiovascular and respiratory complications were also more common among these women, as was maternal death, 4.2 (2.2-8.0). Newborns of OSA patients were at elevated risk of being premature, 1.3 (1.2-1.5) and having congenital abnormalities, 2.3 (1.7-3.0).

CONCLUSIONS

Pregnancies with OSA were linked to an elevated risk of poor maternal and neonatal outcomes. During pregnancy, OSA patients should receive attentive follow-up care in a tertiary hospital.

Early developmental outcome in children born to mothers with obstructive sleep apnea

Obstructive sleep apnea (OSA) during pregnancy leads to adverse maternal and perinatal outcomes. There have been limited studies evaluated the effect of intrauterine exposure to maternal OSA on childhood developmental outcomes. This study was aimed to evaluate the early development of children born to mothers with gestational OSA and the impact of continuous positive airway pressure (CPAP) treatment. METHODS: Children aged 6-36 months, born to high risk pregnant mothers who had overnight polysomnography performed, were invited to participate. The Ages and Stages Questionnaires, third edition (ASQ-3), age-specific parent-completed questionnaires determining five developmental domains (communication, gross motor, fine motor, problem-solving, and personal-social) were used for developmental screening. Children who had a score of at least one domain less than -1 SD of age cut-off were determined as having a risk of developmental delay (RDD). RESULTS: There were 159 children (47% male, mean age 18 months) enrolled. The maternal PSG showed non-OSA, mild OSA, and moderate OSA in 14%, 46%, and 40%, respectively. Forty-two children (26%) had RDD, and the most affected domains were fine motor and problem-solving. Maternal moderate OSA was significantly associated with RDD (adjusted OR 5.39, 95%CI 1.11-26.12, P 0.037). Subgroup analysis showed that maternal moderate OSA with no CPAP treatment was significantly associated with RDD (OR 6.43, 95%CI 1.34-30.89, P = 0.020) CONCLUSION: Gestational moderate OSA in high-risk pregnancy mothers likely had a negative effect on early childhood developmental outcomes, particularly the mothers who did not have appropriate CPAP treatment.

Effect of Maternal Obstructive Sleep Apnea-Hypopnea on 24-Hour Blood Pressure, Nocturnal Blood Pressure Dipping and Arterial Stiffness in Hypertensive Disorders of Pregnancy

Rationale: Maternal obstructive sleep apnea-hypopnea (OSAH) is associated with hypertensive disorders of pregnancy (HDP). Attenuation of the normal nocturnal blood pressure (BP) decline (non-dipping) is associated with adverse pregnancy outcomes. OSAH is associated with nocturnal non-dipping in the general population, but this has not been studied in pregnancy. We therefore analyzed baseline data from an ongoing RCT (NCT03309826) assessing the impact of OSAH treatment on HDP outcomes, to evaluate the relationship of OSAH to 24-h BP profile, in particular nocturnal BP dipping, and measures of arterial stiffness.

Methods: Women with a singleton pregnancy and HDP underwent level II polysomnography. Patients with OSAH (apnea-hypopnea index (AHI) ≥ 5 events/h) then underwent 24-h ambulatory BP monitoring and arterial stiffness measurements (applanation tonometry, SphygmoCor). Positive dipping was defined as nocturnal systolic blood pressure (SBP) dip ≥ 10%. The relationships between measures of OSAH severity, measures of BP and arterial stiffness were evaluated using linear regression analyses.

Results: We studied 51 HDP participants (36.5 ± 4.9 years, BMI 36.9 ± 8.6 kg/m²) with OSAH with mean AHI 27.7 ± 26.4 events/h at 25.0 ± 4.9 weeks’ gestation. We found no significant relationships between AHI or other OSA severity measures and mean 24-h BP values, although BP was generally well-controlled. Most women were SBP non-dippers (78.4%). AHI showed a significant inverse correlation with % SBP dipping following adjustment for age, BMI, parity, gestational age, and BP medications (β = −0.11, p = 0.02). Significant inverse correlations were also observed between AHI and DBP (β = −0.16, p = 0.01) and MAP (β = −0.13, p = 0.02) % dipping. Oxygen desaturation index and sleep time below SaO₂ 90% were also inversely correlated with % dipping. Moreover, a significant positive correlation was observed between carotid-femoral pulse wave velocity (cfPWV) and REM AHI (β = 0.02, p = 0.04) in unadjusted but not adjusted analysis.

Conclusion: Blood pressure non-dipping was observed in a majority of women with HDP and OSAH. There were significant inverse relationships between OSAH severity measures and nocturnal % dipping. Increased arterial stiffness was associated with increasing severity of OSAH during REM sleep in unadjusted although not adjusted analysis. These findings suggest that OSAH may represent a therapeutic target to improve BP profile and vascular risk in HDP.

The association between obstructive sleep apnea and the risk of poor delivery events in women: A population-based nested case-control study

Purpose

To investigate the risk of poor delivery events (PDEs; premature delivery, abortion, and stillbirth) in female subjects with obstructive sleep apnea (OSA).

Methods

The study identified 8346 female subjects with PDEs as cases between January 1, 2000 and December 31, 2015 from the Longitudinal Health Insurance Database 2005 in Taiwan. A total of 33,384 controls were also identified based on frequency matching for age and year of index date. Diagnoses of OSA and PDEs were determined according to the International Classification of Diseases, 9th Revision. The risk of PDEs in female subjects with OSA was estimated with conditional logistic regression analyses.

Findings

The mean age of the 41,730 female subjects was 35.53 years. The overall incidence rate of PDEs was 506.22 per 100,000 person‐years for subjects with OSA, which was significantly higher than that for the controls (501.95 per 100,000 person‐years). The risk of PDEs was higher in subjects with OSA than in controls (adjusted odds ratio [AOR] = 1.19; 95% confidence interval [CI] [95% CI]: 1.08–1.43), including for premature delivery (AOR = 1.20; 95% CI: 1.16–1.50), and abortion (AOR = 1.19; 95% CI: 1.09–1.47). OSA showed no relation to stillbirth (AOR = 1.04; 95% CI: 0.99–1.31). The findings indicate that the longer a subject has been experiencing OSA, the higher the probability of PDEs.

Conclusions

The risk of PDEs associated with OSA was found in this study. In particular, the longer a subject has OSA, the higher the likelihood of PDEs, exhibiting a dose–response effect.

Clinical relevance

To effectively promote maternal health in clinical practice, health providers need to recognize OSA as a risk factor associated with negative pregnancy outcomes. Furthermore, OSA symptoms should be assessed and managed in all pregnant women to enable more comprehensive maternal care.

Predicting perinatal outcomes with an obstructive sleep apnea screening tool

The objective was to determine if a screening tool for obstructive sleep apnea could be used to predict adverse perinatal outcomes. This was a prospective observational study of patients receiving prenatal care and universally screened for obstructive sleep apnea with the STOP Questionnaire (four questions related to Snoring, Tiredness during daytime, Observed apnea, and high blood Pressure). Confounding variables were included in a backwards logistic regression model to predict adverse perinatal outcomes. The study population of 442 women had positive STOP screens (64; 14.5%) associated with preterm delivery and neonatal intensive care unit admissions. For preterm delivery, history of preterm delivery was the strongest predictor with odds ratios of 4.2 (95% confidence interval 2.0-8.8; p < 0.001), followed by STOP, odds ratios 2.8 (95% confidence interval 1.4-5.8; p = 0.004) and nulliparity, odds ratios 2.3 (95% confidence interval 1.2-4.4; p = 0.013). A positive STOP was the only significant predictor for neonatal intensive care unit admissions, odds ratios 2.5 (95% confidence interval 1.1-5.7; p = 0.036). STOP screening test performance indicated low sensitivity but high specificity: preterm delivery (28.3%, 87.4%), neonatal intensive care unit admissions (27.3%, 86.6%), low birth weight (25.0%, 86.9%), and preeclampsia (16.7%, 85.6%). As a stand-alone tool, the STOP Questionnaire has limited performance, but could be explored in combination with other factors that might increase sensitivity to predict preterm delivery and neonatal intensive care unit admission.

Poor sleep is associated with higher blood pressure and uterine artery pulsatility index in pregnancy: a prospective cohort study

OBJECTIVE

To elucidate the association between sleep disturbances and blood pressure as well as uterine artery Doppler during pregnancy in women with no pre-existing hypertension.

DESIGN

Prospective cohort study.

SETTING

Outpatient specialist clinics at KK Women's and Children's Hospital, Singapore.

POPULATION

Women with viable singleton pregnancies confirmed by ultrasonography at less than 14 weeks of amenorrhoea at first visit.

METHODS

In all, 926 subjects were recruited for this study in the outpatient specialist clinics at KK Women's and Children's Hospital, Singapore, between 1 September 2010 and 31 August 2014. They were followed up throughout pregnancy with sleep quality, blood pressure and uterine artery Doppler assessed at each visit.

MAIN OUTCOME MEASURES

Sleep quality, blood pressure and uterine artery Doppler.

RESULTS

Sleep progressively worsened as pregnancy advanced. Shorter sleep duration and poorer sleep efficiency were associated with higher blood pressure, especially in the first trimester. Mixed model analysis demonstrated an overall positive association between sleep quality represented by Pittsburgh Sleep Quality Index (PSQI) score and diastolic blood pressure (DBP) (P < 0.001) and mean arterial pressure (MAP) (P = 0.005) during pregnancy after considering all trimesters. Sleep duration was found to be negatively associated with both systolic blood pressure (SBP) (P = 0.029) and DBP (P = 0.002), whereas sleep efficiency was negatively correlated with DBP (P = 0.002) only. Overall poor sleep during pregnancy was also found to be associated with a higher uterine artery pulsatility index.

CONCLUSION

Our prospective study demonstrated that poor sleep quality is significantly associated with higher blood pressure and uterine artery pulsatility index during pregnancy.

TWEETABLE ABSTRACT

Poor sleep quality is significantly associated with higher blood pressure and higher uterine artery pulsatility index during pregnancy.

The level of depression, anxiety, and sleep quality in pregnancy during coronavirus disease 2019 pandemic

Aim

We aimed to evaluate the mental health and sleep quality of pregnant women in different trimesters during coronavirus disease 2019 (COVID‐19) pandemic and investigate the effect of quarantine and new lifestyle changes that come into our lives with pandemic with on this subject.

Methods

It was conducted on pregnant women (n = 149) who attended routine pregnancy prenatal visit during their pregnancy weeks. The data were collected using sociodemographic and clinical data form, Pittsburgh Sleep Quality Index (PSQI) to evaluate sleep quality, Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI) to evaluate maternal depression and anxiety.

Results

A significant correlation was observed between the week of gestation and depression, anxiety, and defective sleep scores (p < 0.001). A moderate positive correlation was found between the week of gestation and depression (r: 0.628). A high level of positive correlation was found between the week of gestation and defective sleep quality and anxiety scores (r: 0.858, r: 0.754). A statistically significant increase in depression, anxiety, and defective sleep quality was found in the group staying in home quarantine (p = 0.002).

Conclusion

This study showed that the COVID‐19 pandemic can cause depression, anxiety, and serious sleep disorders in pregnant women. The depression and anxiety scores of pregnant women in home quarantine were also found to be higher than the group not in quarantine. As the week of gestation progresses, mental health symptoms worsen and sleep quality deteriorates.

Impact of Obstructive Sleep Apnea on Gestational Diabetes Mellitus

INTRODUCTION

Obstructive sleep apnea (OSA) increases the risk of type 2 diabetes, and hyperinsulinemia. Pregnancy increases the risk of OSA; however, the relationship between OSA and gestational diabetes mellitus (GDM) is unclear. We aimed (1) to evaluate OSA prevalence in GDM patients; (2) to assess the association between OSA and GDM; and (3) to determine the relationships between sleep parameters with insulin resistance (IR).

METHODS

A total of 177 consecutive women (89 with GDM, 88 controls) in the third trimester of pregnancy underwent a hospital polysomnography. OSA was defined when the apnea-hypopnea index (AHI) was ≥5h-1.

RESULTS

Patients with GDM had higher pregestational body mass index (BMI) and neck circumference than controls, but no differences in snoring or OSA-symptoms, or AHI (3.2±6.0 vs. 1.9±2.7h-1, p=.069). OSA prevalence was not significantly different in both groups. We did not identify OSA as a GDM risk factor in the crude analysis 1.65 (95%CI: 0.73-3.77; p=.232). Multiple regression showed that total sleep time (TST), TST spent with oxygen saturation<90% (T90), and maximum duration of respiratory events as independent factors related with homeostasis model assessment of IR, while T90 was the only independent determinant of quantitative insulin sensitivity check index.

CONCLUSION

OSA prevalence during the third trimester of pregnancy was not significantly different in patients with GDM than without GDM, and no associations between OSA and GDM determinants were found. We identified T90 and obstructive respiratory events length positive-related to IR, while TST showed an inverse relationship with IR in pregnant women.

Sleep-disordered breathing in pregnancy: a developmental origin of offspring obesity?

Sleep-disordered breathing (SDB) worsens over pregnancy, and obstructive sleep apnea is associated with serious maternal complications. Intrauterine exposures that provoke insulin resistance (IR), inflammation, or oxidative stress may have long-term offspring health consequences. In obesity, worsening maternal SDB appears to be an exposure that increases the risk for both small- or large-for-gestational-age (SGA, LGA, respectively), suggesting distinct outcomes linked to a common maternal phenotype. The aim of this paper is to systematically review and link data from both mechanistic rodent models and descriptive human studies to characterize the impact of maternal SDB on fetal development. A systematic review of the literature was conducted using PubMed, Embase, and CINAHL (01/2000-09/2019). Data from rodent (9 studies) and human models (48 studies, 5 meta-analyses) were included and reviewed using PRISMA guidelines. Evidence from rodent models suggests that intermittent maternal hypoxia results in mixed changes in birth weight (BW) followed by accelerated postnatal growth, while maternal sleep fragmentation results in normal BW followed by later metabolic derangement. Human studies support that maternal SDB is associated with both SGA and LGA, both of which may predispose offspring to later obesity. Evidence also suggests a link between SDB, inflammation, and oxidative stress that may impact maternal metabolism and/or placental function. SDB is common in pregnancy and affects fetal growth and development. Given that SDB has significant potential to adversely influence the intrauterine metabolic environment, larger, prospective studies in humans are urgently needed to fully elucidate the effects of this exposure on offspring metabolic risk.

Associations of Sleep With Sedentary Behavior and Physical Activity Patterns Across Pregnancy Trimesters

INTRODUCTION

Sleep, sedentary behavior, and moderate-to-vigorous physical activity (MVPA) are altered in pregnancy and may affect pregnancy health; however, how these behaviors are associated with each other is unclear.

METHODS

Pregnant women (N = 120) completed the Pittsburgh Sleep Quality Index and wore an activPAL3 micro and ActiGraph GT3X for 7 days in each trimester to assess sleep, sedentary behavior, and MVPA, respectively. Latent trajectories described patterns of sleep duration, efficiency, and quality as well as sedentary behavior and MVPA. Multinomial logistic regression examined associations of sleep patterns with sedentary behavior and MVPA patterns and, in exploratory analyses, with adverse pregnancy outcomes.

RESULTS

Trajectories were identified for sleep duration (consistently short, 20.7% of sample; consistently adequate, 79.3%), efficiency (consistently low, 17.5%; consistently high, 82.5%), and quality (consistently poor, 15.1%; worsening, 23.5%; and consistently good, 61.5%). Compared with those in more optimal sleep groups, women in the short duration, low efficiency, and worsening quality groups had lower odds of being in the moderate and/or high sedentary behavior group (odds ratio range, 0.21-0.31; 95% confidence interval range, 0.09-0.65). Women in the worsening quality group had greater odds of being in the low MVPA group (odds ratio, 2.51; 95% confidence interval, 1.18-5.38). Trends were observed with women in less optimal sleep groups having greater odds of adverse pregnancy outcomes and lower odds of excessive gestational weight gain.

CONCLUSIONS

Less optimal sleep patterns in pregnancy are associated with less sedentary behavior and MVPA; additional research is needed to confirm associations between sleep and pregnancy outcomes.

Is snoring during pregnancy a predictor of later life obstructive sleep apnoea? A case-control study

BACKGROUND

Obstructive sleep apnoea (OSA) appears common in pregnancy. Complications of pregnancy such as gestational diabetes and hypertension predispose women to cardiometabolic disease in later life. It is unknown if snoring during pregnancy is a risk marker for later-life OSA.

METHODS

We analysed data from N = 897 women in the Sleep Apnea Global Interdisciplinary Consortium (SAGIC), which recruited patients attending sleep clinics at 11 sites. There were 577 cases with current OSA and 320 controls. Cases were further categorised into mild, moderate, and severe OSA based on apnoea-hypopnoea index. Retrospective self-report of snoring during pregnancy was the exposure of interest and was reported by 2.9% of cases and 3.4% of controls.

RESULTS

Multinomial regression demonstrated that snoring during a previous pregnancy was not significantly associated with mild (OR 0.34, 95% CI 0.09-1.25, p = 0.10), moderate (OR 0.69, 95% CI 0.21-2.19, p = 0.52), or severe OSA (OR 1.86, 95% CI 0.77-4.48, p = 0.17) compared to no snoring during pregnancy. Results were unchanged after adjustment for age, body mass index, and ethnicity. 79% of women reported current snoring but all who snored during pregnancy reported current snoring.

CONCLUSIONS

Women who snore during pregnancy continue snoring in later-life but do not appear more likely to develop OSA. These findings are limited by self-reported data, recall bias, and small numbers of women who reported snoring during pregnancy. A prospective study with objective measurement of sleep and snoring during pregnancy is needed to examine the links between sleep disorders in pregnancy with health in later life.

Evaluation of obstructive sleep apnea prevalence in mothers of infants with low birth weight and its relationship with serum uric acid levels as a hypoxia marker

OBJECTIVE

Serum uric acid level, which is an oxidative stress marker, may increase in some conditions that lay the ground for the hypoxia. However, recent literature lacks studies with large series on this subject. We aimed to examine the incidence of OSAS in mothers who delivered a low birth weight baby and its association with serum uric acid levels as a hypoxia marker.

METHODS

We enrolled 143 pregnant women, 44 of whom delivered a low birth weight (LBW) baby. We made a face-to-face interview in which we asked the questions in the patient follow-up form, comprising three sections. The form included questions regarding the sociodemographic features and obstetric history of the participant women, besides the Berlin Questionnaire and the Epworth Sleepiness Scale. We recorded the blood test parameters that are obtained from patient records in the last section.

RESULTS

Mean uric acid (UA) levels of mothers with a LBW baby (n = 44, birth weight below 2500 g) were 4.51 ± 1.23 mg/dL (min-max = 2.7-8.0) while the UA levels in mothers of normal weighted (NBW) babies (n = 99, birth weight is 2500 g or above) were 4.08 ± 0.75 (min-max = 2.6-6.1 mg/dL). The UA levels of mothers who delivered LBW infants were significantly higher compared with the mothers of NBW babies (p = .010).

CONCLUSION

Uric acid levels can be used as a prognostic parameter for the closer monitoring of pregnant women who have been diagnosed with small-for-gestational-age babies during pregnancy.

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 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.

The effect of sleep impairment on gestational diabetes mellitus: a systematic review and meta-analysis of cohort studies

OBJECTIVE

This systematic review and meta-analysis evaluated the influence of sleep duration or impairment (poor sleep quality, snoring, and obstructive sleep apnea [OSA]) on gestational diabetes mellitus (GDM) risk.

METHODS

PubMed, Embase, EBSCO, and WOS databases were searched up to March 4th, 2019. Cohort studies were included and relative risk (RR) with 95% confidence interval (CI) were used as the measure of effects. Heterogeneity was assessed by the Chi-squared and I² tests. Subgroup analyses, sensitivity analysis, and dose-response analysis were performed. The overall quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

A total of 16 studies with 2,551,017 pregnant women and 142,103 GDM cases were included in this study. Both short and long sleep duration were associated with increased risk of GDM. There was a U-shaped relationship between sleep duration and GDM risk (P_{-nonlinearity} < 0.001), and pregnant women with 8 h of sleep presented lower GDM risk. Poor sleep quality, snoring and OSA also increased the subsequent risk of GDM.

CONCLUSIONS

Pregnant women should be made aware of the benefits of proper sleep, and those with poor sleep quality, snoring, and OSA should be screened for GDM.

The effect of maternal obstructive sleep apnea on the placenta

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) during pregnancy has been associated with adverse maternal outcomes. However, the effect of maternal OSA on fetal growth is less clear. The placenta is a critical organ for fetal growth and development and the principal determinant of birthweight. We aimed to investigate the effect of maternal OSA on placental growth and function.

METHODS

Placentas of women recruited to a prospective longitudinal study were consecutively obtained immediately after delivery. Each placenta was measured for length, width, and thickness. Total RNA was isolated for gene expression analysis of VEGF, VEGF receptor, PIGF, and leptin. Histological and morphometric evaluations of the placenta were performed.

RESULTS

A total of 53 placentas were investigated. Ten women (19%) had OSA, and the weight of their placentas was significantly higher compared with the placentas of the controls (526.1 ± 83.9 vs. 425.7 ± 95.5 g, p = 0.004). There was a significant positive correlation between placental weight and the log apnea-hypopnea index even after controlling for maternal body mass index (BMI; r = 0.31, p = 0.04). The birthweight/placental weight ratio was significantly lower in women with OSA compared with controls (p = 0.03). Placental weight and newborn triceps adiposity thickness correlated positively after controlling for maternal BMI (r = 0.29, p = 0.04). Leptin expression was 1.8-fold higher in placentas of women with OSA compared with controls (p = 0.02). No histological differences were found between the groups.

CONCLUSIONS

Maternal OSA is associated with increased placental weight that correlated with OSA severity and neonatal adiposity independently of maternal BMI. Placental leptin overexpression may mediate/underlie the above findings.Trial Registration: Clinical Trials NCT00931099.

Intermittent Hypoxia Impairs Trophoblast Cell Viability by Triggering the Endoplasmic Reticulum Stress Pathway

Intermittent hypoxia (IH) is a prominent characteristic of many clinical complications such as obstructive sleep apnea syndrome (OSAS). OSAS is related to a higher incidence of adverse pregnancy outcomes, and IH has been suggested as the preliminary physiological etiology. However, further studies remain to be performed on the underlying cellular and molecular pathogenic mechanisms of OSAS-related IH on adverse pregnancy outcomes. Here, we used a trophoblast cell line (HTR8/SVneo), primary extravillous trophoblast cells (EVTs), and a normal-term placenta villi explant culture model in vitro in this research. The effects and possible molecular mechanisms of IH on trophoblast motility, cell cycle progression, and apoptosis were investigated. IH reduced HTR8/SVneo cell and EVT motility significantly, which could be partially attributed to the reduced secretion of matrix metalloproteinase 2. IH treatment blocked HTR8/SVneo cell proliferation significantly by modulating the expression of D-type Cyclins. IH also induced significant trophoblast cell apoptosis. Moreover, our study supports the premise that IH attenuates trophoblast cell motility and proliferation and induces excessive trophoblast cell apoptosis by specifically triggering the endoplasmic reticulum (ER) stress signaling pathway. Briefly, differing from the mechanism of trophoblast motility and proliferation inhibition, and apoptosis induction by hypoxia, IH is apt to weaken trophoblast viability mainly by activating the ER stress signaling pathway with a time-dependent pattern, which is further implicated in OSAS-associated adverse pregnancy outcomes.

Impact of inflammation on developing respiratory control networks: rhythm generation, chemoreception and plasticity

The respiratory control network in the central nervous system undergoes critical developmental events early in life to ensure adequate breathing at birth. There are at least three "critical windows" in development of respiratory control networks: 1) in utero, 2) newborn (postnatal day 0-4 in rodents), and 3) neonatal (P10-13 in rodents, 2-4 months in humans). During these critical windows, developmental processes required for normal maturation of the respiratory control network occur, thereby increasing vulnerability of the network to insults, such as inflammation. Early life inflammation (induced by LPS, chronic intermittent hypoxia, sustained hypoxia, or neonatal maternal separation) acutely impairs respiratory rhythm generation, chemoreception and increases neonatal risk of mortality. These early life impairments are also greater in young males, suggesting sex-specific impairments in respiratory control. Further, neonatal inflammation has a lasting impact on respiratory control by impairing adult respiratory plasticity. This review focuses on how inflammation alters respiratory rhythm generation, chemoreception and plasticity during each of the three critical windows. We also highlight the need for additional mechanistic studies and increased investigation into how glia (such as microglia and astrocytes) play a role in impaired respiratory control after inflammation. Understanding how inflammation during critical windows of development disrupt respiratory control networks is essential for developing better treatments for vulnerable neonates and preventing adult ventilatory control disorders.

Sleep in Pregnancy and Maternal Hyperglycemia: a Narrative Review

PURPOSE OF REVIEW

Prevalence of gestational diabetes is increasing globally and sleep may be a modifiable lifestyle factor associated with it. However, existing findings have been inconsistent.

RECENT FINDINGS

Majority of studies reviewed found a link between extreme sleep durations and elevated risk of maternal hyperglycemia. The findings with sleep-disordered breathing are less consistent. Methodological differences across studies, in terms of sleep assessment methods (subjective vs. objective), study population (low vs. high risk), classification of gestational diabetes and sleep problems, may have contributed to the inconsistent findings. Some studies also suggest the possibility of trimester-specific association between sleep and maternal hyperglycemia. Large-scale prospective studies comprising objective measurements of sleep, preferably over three trimesters and preconception, are needed to better evaluate the relationship between sleep and maternal hyperglycemia.

Obstructive Sleep Apnea in Pregnant Women: A Review of Pregnancy Outcomes and an Approach to Management

Among obese pregnant women, 15%-20% have obstructive sleep apnea (OSA) and this prevalence increases along with body mass index and in the presence of other comorbidities. Prepregnancy obesity and pregnancy-related weight gain are certainly risk factors for sleep-disordered breathing in pregnancy, but certain physiologic changes of pregnancy may also increase a woman's risk of developing or worsening OSA. While it has been shown that untreated OSA in postmenopausal women is associated with a range of cardiovascular, pulmonary, and metabolic comorbidities, a body of literature is emerging that suggests OSA may also have serious implications for the health of mothers and fetuses during and after pregnancy. In this review, we discuss the following: pregnancy as a vulnerable period for the development or worsening of OSA; the associations between OSA and maternal and fetal outcomes; the current screening modalities for OSA in pregnancy; and current recommendations regarding peripartum management of OSA.

Prediction of pre-eclampsia: review of reviews

OBJECTIVE

Primary studies and systematic reviews provide estimates of varying accuracy for different factors in the prediction of pre-eclampsia. The aim of this study was to review published systematic reviews to collate evidence on the ability of available tests to predict pre-eclampsia, to identify high-value avenues for future research and to minimize future research waste in this field.

METHODS

MEDLINE, EMBASE and The Cochrane Library including DARE (Database of Abstracts of Reviews of Effects) databases, from database inception to March 2017, and bibliographies of relevant articles were searched, without language restrictions, for systematic reviews and meta-analyses on the prediction of pre-eclampsia. The quality of the included reviews was assessed using the AMSTAR tool and a modified version of the QUIPS tool. We evaluated the comprehensiveness of search, sample size, tests and outcomes evaluated, data synthesis methods, predictive ability estimates, risk of bias related to the population studied, measurement of predictors and outcomes, study attrition and adjustment for confounding.

RESULTS

From 2444 citations identified, 126 reviews were included, reporting on over 90 predictors and 52 prediction models for pre-eclampsia. Around a third (n = 37 (29.4%)) of all reviews investigated solely biochemical markers for predicting pre-eclampsia, 31 (24.6%) investigated genetic associations with pre-eclampsia, 46 (36.5%) reported on clinical characteristics, four (3.2%) evaluated only ultrasound markers and six (4.8%) studied a combination of tests; two (1.6%) additional reviews evaluated primary studies investigating any screening test for pre-eclampsia. Reviews included between two and 265 primary studies, including up to 25 356 688 women in the largest review. Only approximately half (n = 67 (53.2%)) of the reviews assessed the quality of the included studies. There was a high risk of bias in many of the included reviews, particularly in relation to population representativeness and study attrition. Over 80% (n = 106 (84.1%)) summarized the findings using meta-analysis. Thirty-two (25.4%) studies lacked a formal statement on funding. The predictors with the best test performance were body mass index (BMI) > 35 kg/m² , with a specificity of 92% (95% CI, 89-95%) and a sensitivity of 21% (95% CI, 12-31%); BMI > 25 kg/m² , with a specificity of 73% (95% CI, 64-83%) and a sensitivity of 47% (95% CI, 33-61%); first-trimester uterine artery pulsatility index or resistance index > 90^th centile (specificity 93% (95% CI, 90-96%) and sensitivity 26% (95% CI, 23-31%)); placental growth factor (specificity 89% (95% CI, 89-89%) and sensitivity 65% (95% CI, 63-67%)); and placental protein 13 (specificity 88% (95% CI, 87-89%) and sensitivity 37% (95% CI, 33-41%)). No single marker had a test performance suitable for routine clinical use. Models combining markers showed promise, but none had undergone external validation.

CONCLUSIONS

This review of reviews calls into question the need for further aggregate meta-analysis in this area given the large number of published reviews subject to the common limitations of primary predictive studies. Prospective, well-designed studies of predictive markers, preferably randomized intervention studies, and combined through individual-patient data meta-analysis are needed to develop and validate new prediction models to facilitate the prediction of pre-eclampsia and minimize further research waste in this field. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Obstructive Sleep Apnea Is Associated With Altered Glycemic Patterns in Pregnant Women With Obesity

OBJECTIVE

Often unrecognized, obstructive sleep apnea (OSA) worsens over pregnancy and is associated with poorer perinatal outcomes. The association between OSA in late pregnancy and metabolic biomarkers remains poorly understood. We tested the hypothesis that OSA in pregnant women with obesity is positively correlated with 24-hour patterns of glycemia and IR despite controlling for diet.

DESIGN

Pregnant women (32 to 34 weeks' gestation; body mass index, 30 to 40 kg/m2) wore a continuous glucose monitor for 3 days. OSA was measured in-home by WatchPAT 200™ [apnea hypopnea index (AHI), oxygen desaturation index (ODI; number per hour)]. Fasting blood was collected followed by a 2-hour, 75-g, oral glucose tolerance test to measure IR. Association between AHI and 24-hour glucose area under the curve (AUC) was the powered outcome.

RESULTS

Of 18 women (29.4 ± 1.4 years of age [mean ± SEM]), 12 (67%) had an AHI ≥5 (mild OSA). AHI and ODI were correlated with 24-hour glucose AUC (r = 0.50 to 0.54; P ≤ 0.03) and mean 24-hour glucose (r = 0.55 to 0.59; P ≤ 0.02). AHI and ODI were correlated with estimated hepatic IR (r = 0.59 to 0.74; P < 0.01), fasting free fatty acids (fFFAs; r = 0.53 to 0.56; P < 0.05), and waking cortisol (r = 0.49 to 0.64; P < 0.05).

CONCLUSIONS

Mild OSA is common in pregnant women with obesity and correlated with increased glycemic profiles, fFFAs, and estimates of hepatic IR. OSA is a potentially treatable target to optimize maternal glycemia and metabolism, fetal fuel supply, and pregnancy outcomes.

An Epworth Sleep Score ≥11 is associated with emergency operative birth and poor neonatal composite outcome at term

BACKGROUND

During pregnancy, the Epworth Sleepiness Scale can be used as a surrogate marker for maternal sleep-disordered breathing, a condition that is becoming increasingly prevalent in obstetric populations and is associated with a multitude of pregnancy complications.

AIMS

The aim of this observational study was to investigate the relationship between the Epworth Sleepiness Scale score and indication and mode of delivery during pregnancy.

MATERIALS AND METHODS

The Epworth Sleepiness Scale was completed by 178 women at Mater Mothers' Hospital, Brisbane, Australia.

RESULTS

Women with a score ≥11 were less likely to achieve a spontaneous vaginal delivery (aOR 0.43, 95% CI 0.21-0.88, P = 0.02), and were more likely to have an instrumental (aOR 2.81, 95% CI 1.30-6.08, P = 0.01) or any operative birth (instrumental and caesarean section aOR 2.32, 95% CI 1.14-4.71, P = 0.02). These women were also more likely to have an operative birth for intrapartum fetal compromise (aOR 2.62, 95% CI 1.21-5.69, P = 0.015), as well as an infant with poor neonatal outcomes (aOR 2.77, 95% CI 1.09-7.03, P = 0.03).

CONCLUSIONS

These results show that symptoms of sleep-disordered breathing are associated with emergency operative birth, particularly when the indication for operative birth was intrapartum fetal compromise.

The STOP-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea in Pregnancy

STUDY OBJECTIVES

We examined the validity of the STOP-Bang questionnaire and a modified STOP-Bang questionnaire to screen for obstructive sleep apnea (OSA) in women with obesity during the second trimester of pregnancy.

METHODS

Ninety-nine pregnant women age 18 years or older with body mass index ≥ 40 kg/m² completed the STOP-Bang questionnaire during their second trimester. The number of oxygen desaturation events (≥ 4% from baseline) was measured using overnight pulse oximetry, with OSA defined as ≥ 5 events/h. A Modified STOP-Bang score was derived by replacing the "Tired" item with Epworth Sleepiness Scale score ≥ 10. Seven candidate models were compared using information theoretic criteria: STOP-Bang, Modified STOP-Bang, and individual STOP-Bang items (Snore, Tired, Observed to stop breathing, high blood Pressure and Neck circumference). We used penalized logistic regression and negative binomial regression to derive predicted probabilities of having OSA and the predicted total event counts.

RESULTS

The predicted probability of meeting oximetry criteria for OSA increased with higher STOP-Bang scores, from < 10% for a score < 3 to 68% with a score of 6. The total number of disordered breathing events was 1.26 (95% confidence interval 1.06 to 1.50) times greater for a 1-unit increase in STOP-Bang. Of the candidate models, the best relative fit was the Snore item followed by STOP-Bang score (essentially equivalent). The predicted probability of having OSA was 5.0% for no snoring and 26.4% for snoring.

CONCLUSIONS

STOP-Bang has been shown to be a useful screening tool for OSA in pregnant women with obesity; however, the snoring question alone might be a simpler, effective predictor.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: STOPBANG As A Screening Tool for Obstructive Sleep Apnoea in Pregnancy; URL: https://clinicaltrials.gov/ct2/show/NCT02542488; Identifier: NCT02542488.

The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight

OBJECTIVE

To evaluate the effect, on birth weight and birth weight centile, of use of the PrenaBelt, a maternal positional therapy device, during sleep in the home setting throughout the third trimester of pregnancy.

DESIGN

A double-blind, sham-controlled, randomised clinical trial.

SETTING

Conducted from September 2015 to May 2016, at a single, tertiary-level centre in Accra, Ghana.

PARTICIPANTS

Two-hundred participants entered the study. One-hundred-eighty-one participants completed the study. Participants were women, 18 to 35 years of age, with low-risk, singleton, pregnancies in their third-trimester, with body mass index <35 kg/m² at the first antenatal appointment for the index pregnancy and without known foetal abnormalities, pregnancy complications or medical conditions complicating sleep.

INTERVENTIONS

Participants were randomised by computer-generated, one-to-one, simple randomisation to receive either the PrenaBelt or sham-PrenaBelt. Participants were instructed to wear their assigned device to sleep every night for the remainder of their pregnancy (approximately 12 weeks in total) and were provided a sleep diary to track their use. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants and the outcomes assessor were blinded to allocation.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes were birth weight and birth weight centile. Secondary outcomes included adherence to using the assigned device nightly, sleeping position, pregnancy outcomes and feedback from participants and maternity personnel.

RESULTS

One-hundred-sixty-seven participants were included in the primary analysis. The adherence to using the assigned device nightly was 56%. The mean ±SD birth weight in the PrenaBelt group (n=83) was 3191g±483 and in the sham-PrenaBelt group (n=84) was 3081g±484 (difference 110 g, 95% CI -38 to 258, p=0.14). The median (IQR) customised birth weight centile in the PrenaBelt group was 43% (18 to 67) and in the sham-PrenaBelt group was 31% (14 to 58) (difference 7%, 95% CI -2 to 17, p=0.11).

CONCLUSIONS

The PrenaBelt did not have a statistically significant effect on birth weight or birth weight centile in comparison to the sham-PrenaBelt.

TRIAL REGISTRATION NUMBER

NCT02379728.

Screening extremely obese pregnant women for obstructive sleep apnea

BACKGROUND

Obesity is prevalent among pregnant women in the United States; obstructive sleep apnea is highly comorbid with obesity and is associated with adverse pregnancy outcomes. Screening for obstructive sleep apnea in pregnant women has remained a challenge because of a lack of validated screening tools.

OBJECTIVE

The purpose of this study was to evaluate established obstructive sleep apnea screening tools, a sleepiness scale, and individual component items in a cohort of pregnant women with extreme obesity in mid pregnancy with the use of objective testing to determine obstructive sleep apnea status and to describe the prevalence of obstructive sleep apnea among women with extreme obesity.

STUDY DESIGN

Adult pregnant subjects, between 24 and 35 weeks gestation, with a body mass index ≥40 kg/m² at the time of enrollment completed obstructive sleep apnea screening tools (Berlin Questionnaire, American Society of Anesthesiologists checklist, and STOP-BANG questionnaire) and the Epworth Sleepiness Scale; they also underwent physical examination of the neck, mouth, and airway. The published obstructive sleep apnea in pregnancy prediction score was calculated for each subject. Obstructive sleep apnea status for each subject was determined by the results of an overnight, unattended type III home sleep apnea test.

RESULTS

Twenty-four percent of pregnant women with extreme obesity had obstructive sleep apnea on home sleep apnea testing in mid pregnancy (Apnea-Hypopnea Index, ≥5 events per hour]. Established obstructive sleep apnea screening tools performed very poorly to screen for obstructive sleep apnea in this cohort. Age, body mass index, neck circumference, frequently witnessed apneas, and highly likely to fall asleep while driving were associated most strongly with obstructive sleep apnea status in this cohort.

CONCLUSION

We found that 24% of pregnant women with body mass index ≥40 kg/m² between 24 and 35 weeks gestation have obstructive sleep apnea, defined as Apnea-Hypopnea Index ≥5 events per hour on an overnight type III home sleep apnea test. We found the Berlin Questionnaire, American Society of Anesthesiologists checklist, STOP-BANG, obstructive sleep apnea in pregnancy score by Facco et al, and the Epworth Sleepiness Scale were not useful screening tools for obstructive sleep apnea in a cohort of obese pregnant women. However, age, body mass index, neck circumference, frequently witnessed apneas, and likely to fall asleep while driving were associated with obstructive sleep apnea in this cohort. Further studies are needed to adjust the criteria and thresholds within the available screening tools to better predict obstructive sleep apnea in pregnant women with obesity.