Psychiatric Annals

CME Article 

Obstructive Sleep Apnea in Pregnancy

Sarah Rizvi, MD; Mahdi Awwad, MD; Numan Choudhry, MD; Safia S. Khan, MD

Abstract

Obstructive sleep apnea (OSA) is often undiagnosed and undertreated in women, particularly in women who are pregnant, as the physiologic changes of pregnancy overlap with symptoms of OSA and sleep-disordered breathing, including excessive sleepiness, tiredness, headaches, and gastroesophageal reflux. Pregnant women with sleep apnea have a higher chance of developing high blood pressure, preeclampsia, and gestational diabetes, as well as having a higher chance of premature birth. Treatment with continuous positive airway pressure can effectively reduce blood pressure within a single night, generally by reducing circulating stress hormone levels. Women who have had prior pregnancies with complications should be evaluated for OSA, preferably prior to or in early subsequent pregnancies to reduce maternal-fetal complications. [Psychiatr Ann. 2019;49(12):524–528.]

Abstract

Obstructive sleep apnea (OSA) is often undiagnosed and undertreated in women, particularly in women who are pregnant, as the physiologic changes of pregnancy overlap with symptoms of OSA and sleep-disordered breathing, including excessive sleepiness, tiredness, headaches, and gastroesophageal reflux. Pregnant women with sleep apnea have a higher chance of developing high blood pressure, preeclampsia, and gestational diabetes, as well as having a higher chance of premature birth. Treatment with continuous positive airway pressure can effectively reduce blood pressure within a single night, generally by reducing circulating stress hormone levels. Women who have had prior pregnancies with complications should be evaluated for OSA, preferably prior to or in early subsequent pregnancies to reduce maternal-fetal complications. [Psychiatr Ann. 2019;49(12):524–528.]

Clinically, obstructive sleep apnea (OSA) is recognized as a syndrome that is defined by the occurrence of repetitive episodes of complete or partial upper airway obstruction during sleep. These episodes usually occur in association with loud snoring and daytime sleepiness;1 however, operationally, there is much variability in how specific events are identified.2 Tiredness, fatigue, and, in an evolved disease, sleepiness, are common daytime complaints in patients with OSA.1 Sleep fragmentation and deprivation, and the cerebral hemodynamic changes secondary to the apneas, can lead to personality changes with bursts of jealousy, suspicion, anxiety, bouts of deep depression, automatic behavior, recurrent morning headaches, or morning nausea1 (Table 1). These symptoms are commonly seen in the first and second trimester of pregnancy. A small minority of pregnant patients are essentially evaluated for OSA based on these complaints.

Signs and Symptoms and Screening Tools for Diagnosis of OSA

Table 1:

Signs and Symptoms and Screening Tools for Diagnosis of OSA

Multiple studies suggest that the most commonly used screening tools for OSA (the Epworth Sleepiness Scale and Berlin Questionnaire) are likely poor predictors of diagnosis in women who are pregnant.3 Objectively measured short sleep duration has been associated with a higher risk of requiring a cesarean delivery and longer duration of labor.4

Sleep-disordered breathing (SDB) is another sleep condition that has been associated with adverse pregnancy outcomes.4 For instance, SDB increases the risk of gestational diabetes, even after adjusting for body habitus.4

Therefore, it is imperative for the physicians caring for pregnant patients to have a high suspicion for sleep-related breathing disorders from early in the pregnancy. Testing with home-based or laboratory-based polysomnogram can lead to diagnosis and intervention depending on severity of the disorder.

Prevalence

According to a recent report by American Academy of Sleep Medicine, OSA affects 12% of the US adult population (29.4 million people), and 80% of these people are undiagnosed.5 In pregnant women, the prevalence of OSA has been noted to be as high as 20%,6 with increasing incidence as the pregnancy progresses.7

Women are more likely to be underdiagnosed with OSA as they do not present with the classic symptoms of snoring, daytime sleepiness, witnessed apneas, and nocturnal gasping. Instead, they report symptoms of daytime fatigue, morning headaches, and mood disorders, which could mislead clinicians to a different diagnosis8 such as hypothyroidism, endocrine disorders, headache disorders, chronic fatigue syndrome, and mood disorders. Large-scale population studies may be needed to calculate the true prevalence, as population-based estimates are inferred from previous studies.

Pathophysiology of OSA in Pregnancy

Estrogen and progesterone levels rise steadily with each trimester of pregnancy. Progesterone has significant impact on SDB, as it directly stimulates medullary chemoreceptors and, in turn, respiratory drive and alveolar ventilation.9 Oxygen consumption and minute ventilation progressively increase during pregnancy by 20% and 30% to 50%, respectively.9 The increased ventilatory drive may induce obstructive respiratory events by increasing diaphragmatic effort, which creates negative inspiratory pressure on the hyperemic upper airway.9 There is increased risk of airway collapse due to increased ventilatory drive and diaphragmatic elevation secondary to an enlarging uterus. Respiratory changes in pregnancy include a 20% reduction in functional residual capacity,9 similar to volumes seen in patients with restrictive lung disease.

Anatomical narrowing and increased resistance within the respiratory system may occur because increased levels of estrogen and progesterone induce capillary engorgement, hypersecretion, and mucosal edema of the upper airway.3,9 Higher Mallampati scores due to airway narrowing have also been correlated with increased apnea-hypopnea index (AHI) scores during the different trimesters of pregnancy. Pregnancy rhinitis is seen starting in the second trimester in up to 40% of women, with nasal mucosal congestion contributing to reduced airway size, and such findings are consistent on histological examination.9 Congestion and rhinitis, along with fetal movement, heartburn, position and musculoskeletal discomfort, leg cramps, and even uterine contractions are all pregnancy-associated factors that disrupt sleep.3

Finally, frequent awakenings due to pregnancy-related discomfort may cause respiratory instability and periodic breathing at sleep onset.9 The resulting sleep deprivation can also increase arousal threshold, impair upper airway muscle activity, and increase upper airway collapsibility.9

Screening and Diagnostics

A thorough history from patient and partner, physical examination (including screening neck circumferences, Mallampati class, and truncal obesity), questionnaires (Berlin Questionnaire, Epworth Sleepiness Scale, STOP-BANG [snoring, tiredness, observed apneas, high blood pressure, body mass index, age, neck size, gender]), and presence of comorbid conditions or sleepiness and fatigue will indicate if sleep study evaluation is warranted.

The Epworth Sleepiness Scale is a brief self-administered questionnaire used to assess tendency to fall asleep in certain situations (eg, sitting, reading, as a passenger in a car).4 Excessive or abnormal sleepiness is defined as a total score of >10 in clinical practice. The Berlin Questionnaire assess snoring, sleepiness, and fatigue to evaluate the risk of having OSA. The scoring algorithm of the Berlin Questionnaire is not straight-forward and is somewhat time consuming for the clinician. The STOP-BANG risk evaluation for sleep apnea is a fairly easy tool, conducted by the clinician, shown to have a high sensitivity of 93% to 100% for moderate to severe OSA when the STOP-BANG score is >3.10 Patients with a STOP-BANG score of 0 to 2 are considered at low risk for having moderate to severe OSA.10

Table 1 summarizes the symptoms and assessments recommended by the American Academy of Sleep Medicine for evaluation of OSA. Features to be evaluated that may suggest the presence of OSA include increased neck circumference (>17 inches in men, >16 inches in women), body mass index ≥30 kg/m2, a modified Mallampati score of 3 or 4, the presence of retrognathia, lateral peritonsillar narrowing, macroglossia, tonsillar hypertrophy, elongated/enlarged uvula, high arched/narrow hard palate, nasal abnormalities (polyps, deviation, valve abnormalities, turbinate hypertrophy), and/or overjet.11

The gold standard test for diagnosis of OSA is an overnight laboratory polysomnography,8 although home-based testing may be the preferred alternative for most of these otherwise healthy pregnant women. The diagnosis of OSA is confirmed if the number of obstructive events (apneas + hypopneas + respiratory event-related arousals) divided by total sleep time in hours on polysomnogram is greater than 15 events per hour or greater than 5 per hour in a patient who reports any of the following: unintentional sleep episodes during wakefulness; daytime sleepiness; unrefreshing sleep; fatigue; insomnia; waking up breath holding, gasping, or choking; or the bed partner describing loud snoring, breathing interruptions, or both during the patient's sleep.11 Definitions of apnea, hypopnea, and respiratory-effort related arousals (RERAs) are listed in Table 2. The respiratory disturbance index includes apneas, hypopneas, and RERAs in calculation of severity of SDB. OSA severity is defined as mild for AHI ≥5 and <15 per hour, moderate for AHI ≥15 and ≤30 per hour, and severe for AHI >30 per hour.11

Definitions of Sleep-Related Breathing Events

Table 2:

Definitions of Sleep-Related Breathing Events

Polysomnogram involves an overnight sleep study done in a laboratory while electroencephalographic evidence of sleep stages is monitored and correlated with respiratory events (apneas, hypopneas, RERAs, or central apneas), leg and body movements, pulse oximetry, and limited electrocardiogram. Total sleep time, sleep efficiency, wakefulness after sleep onset, sleep latency, rapid eye movement sleep latency, arousal index, AHI, periodic leg movement index, and abnormalities of electrocardiogram and electroencephalogram are reported. Video monitoring detects presence of abnormal body movements or parasomnias including bruxism, somniloquy, dream enactment behavior, or somnambulism.

At-home sleep apnea tests are used to identify breathing-related events (apneas or hypopneas), heart rate, pulse oximetry, body position, and respiratory effort. AHI, heart rate, oxygen saturation, and body position are reported. Some devices are able to report with fair accuracy the sleep stages and sleep efficiency. The discussion of the various technologies used in these in-laboratory or at-home studies is beyond the scope of this article.

Maternal and Fetal Complications Due to OSA

There is an increased association of maternal hypertension, gestational diabetes, preterm births, and lower birthweights seen in patients with OSA.12–14 Patients at high risk of OSA are at increased risk for preeclampsia/eclampsia in comparison to those at low risk.15 Also, the associations between OSA and preeclampsia are greater in women with comorbid obesity than in women without comorbid obesity.13

The most significant association is the increase in maternal mortality. Women with excessive sleep fragmentation and less than 6 hours of sleep per night during the last trimester are at higher risk of having prolonged labor and increased risk of requiring cesarean delivery. Shorter duration of sleep may lead to decreased leptin and increased ghrelin levels, whereas fragmentation results in increased cortisol release, increasing risk for gestational diabetes, hypertension, preeclampsia, and eclampsia16 (Table 3).

Maternal and Fetal/Neonatal Consequences of Untreated OSA in Pregnancy

Table 3:

Maternal and Fetal/Neonatal Consequences of Untreated OSA in Pregnancy

Women with OSA have an approximately 5-fold increased risk of mortality prior to discharge from the hospital in comparison to women without OSA, regardless of obesity status, even after adjusting for serious cardiovascular, renal, and metabolic settings that affect mortality.17 There is also the increased risk of anesthesia complications in patients with OSA; specifically, there is noted increased risk of postoperative hypoxemia, hypercapnia, and sudden death.18

Management of OSA in Pregnancy

Once the diagnosis of OSA is established, the patient should be included in deciding on an appropriate treatment strategy that may include positive airway pressure devices, oral appliances, behavioral treatments, surgery, and/or adjunctive treatments.11 OSA should be approached as a chronic disease requiring long-term, multidisciplinary management.11

In the general population, CPAP is the preferred treatment for mild, moderate, and severe OSA.11 In singleton (and multiple) pregnancies, CPAP has been shown to reduce hypertension and improve symptoms of OSA.19,20 In patients with severe cases and intolerance to CPAP, tracheostomy is an option to improve management of OSA.21 Despite the fact that it may help, surgery is not recommended for treatment as it increases the risk of adverse outcomes.22

Patients with mild position-dependent OSA without complications may benefit from sleeping in the lateral recumbent or head-elevated position.11 Patients with OSA need to be cautious during intrapartum and postpartum management, mainly related to avoiding respiratory depression. During intrapartum management, it is important to bring their CPAP, other positive pressure devices, or oral appliances with them to be used at the time of somnolence to maintain adequate oxygenation. Pain management during labor and delivery is important to address, mainly administration of early regional anesthesia, to avoid using opioids for labor pains and general anesthesia in the setting of a possible emergency cesarean delivery.23 Postoperative opioids should also be used with caution to avoid respiratory depression.24 Risk of anesthesia complications is relatively higher in patients with OSA. When cesarean delivery is planned or anticipated in patients with OSA or SDB, a “pre-labor” anesthesia consultation may be beneficial to discuss this management with the patient and obstetrician.25

Treatment with CPAP can effectively reduce blood pressure within 1 night,26 generally by reducing circulating stress hormone levels. Patients with mild OSA and increased glycemic profiles may potentially benefit from treatment to help improve maternal glycemia and pregnancy outcomes.27 Improvement in sleep maintenance, quality of sleep, and mood disorders has been elicited in multiple studies in nonpregnant patients; therefore, the benefits in pregnancy are inferred.

Conclusion

Pregnant women and those of reproductive age tend to be healthy overall. Screening for OSA during preconception counseling and routine obstetric visits may lead to earlier diagnosis and prevention of complications. The effects of OSA on pregnancy, delivery, and postpartum outcomes are vast, ranging from maternal complications and increased mortality to multiple adverse childbirth and neonatal outcomes. Management of OSA should not end with delivery of the child. The “fourth” trimester and the preconception period are some of the most crucial times to screen for and treat OSA. Despite the fact that pregnant women may be predisposed to OSA caused by the normal physiological changes associated with the gravid state, the impact of SDB on pregnancy remains undetermined28 and should be the subject of future studies.

References

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Signs and Symptoms and Screening Tools for Diagnosis of OSA

Signs and Symptoms Screening Tools Evaluation and Diagnosis
BMI >30–35 kg/m2 Neck circumference >16 inches in women Snoring Chronic hypertension Advanced maternal age Daytime sleepiness/tired Morning headache Mallampati score of 3 or 4 Witnessed apneas Smoking Snoring, HTN, age, BMIa STOP-BANG Questionnaire Epworth Sleepiness Scaleb Berlin Questionnaireb PSG (gold standard) Home sleep apnea testing Out of center/other overnight sleep testing

Definitions of Sleep-Related Breathing Events

Event Definition
Apnea Peak signal excursions drop ≥90% of pre-event baseline with duration of ≥10 seconds
Hypopnea Peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), positive airway pressure device flow (titration study), or an alternative hypopnea sensor with duration of ≥10 seconds
Respiratory effort-related arousals Air flow reduction not meeting the criteria for apneas or hypopneas, and leads to an arousal

Maternal and Fetal/Neonatal Consequences of Untreated OSA in Pregnancy

<list-item>

■ Maternal complications of untreated OSA <list-item>

Gestational diabetes/insulin resistance

Hypertension

Preeclampsia

Depression

Anxiety

Insomnia

Longer hospital stays

Increased maternal mortality

Increased risk for cesarean delivery

</list-item>

</list-item><list-item>

■ Fetal/neonatal complications of exposure to maternal untreated OSA <list-item>

Low birth weight

Preterm birth

Fetal respiratory distress

Increased risk for cesarean delivery

Longer hospital stays

</list-item>

</list-item>
Authors

Sarah Rizvi, MD, is a Postgraduate Year-3 Resident, Department of Family and Community Medicine. Mahdi Awwad, MD, is an Assistant Professor and the Maternal Care Coordinator, Department of Family and Community Medicine. Numan Choudhry, MD, is a Postgraduate Year-3 Resident, Department of Family and Community Medicine. Safia S. Khan, MD, is an Assistant Professor, Sleep Medicine and Family Medicine, and the Director, Didactics Sleep Medicine Fellowship, University of Texas (UT) Southwestern Medical Center.

Address correspondence to Safia S. Khan, MD, Sleep Medicine and Family Medicine, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390; email: safia.khan@utsouthwestern.edu.

Grant: Safia S. Khan received a grant (FP00012281) for obesity and obstructive sleep apnea in pregnancy research from the National Institutes of Health National Heart, Lung and Blood Institute.

Disclosure: The authors have no relevant financial relationships to disclose.

10.3928/00485713-20191107-01

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