Diagnosis of Obstructive Sleep Apnea During Pregnancy

By Ahizechukwu C. Eke, MD, PhD, MPH

Associate Professor in Maternal Fetal Medicine, Division of Maternal Fetal Medicine, Department of Gynecology & Obstetrics, Johns Hopkins University School of Medicine, Baltimore

SYNOPSIS: Obstructive sleep apnea is associated with several adverse maternal and fetal outcomes.

SOURCE: Frappaolo AM, Linder AH, Wen T, et al. Trends in and outcomes associated with obstructive sleep apnea during deliveries in the United States, 2000-2019. Am J Obstet Gynecol MFM 2022; Nov 16:100775. doi: 10.1016/j.ajogmf.2022.100775. [Online ahead of print].

Obstructive sleep apnea (OSA), defined as a sleep disorder characterized by recurrent episodes of partial or complete obstruction of the upper respiratory airways during sleep that results in a temporary cessation of breathing and airway exchange, is increasingly becoming diagnosed during pregnancy.^1,2 Respiratory obstruction related to OSA typically occurs from relaxation of the muscles of the posterior neck and pharynx. As the result of several issues, such as lack of optimal OSA screening instruments validated for use during pregnancy and lack of proper understanding of the effect of OSA on maternal and perinatal outcomes, OSA has received little attention and has been an understudied risk factor for adverse pregnancy complications.^2,3

OSA has been associated with several adverse maternal, neonatal, and infant outcomes, including gestational diabetes, preeclampsia, maternal excessive weight gain, preterm labor, preterm delivery, low birth weight, small for gestational age, intrauterine fetal growth restriction, and increased risk for cesarean delivery.^2-4 Although older studies suggest that the prevalence of OSA in the United States is increasing, these studies were limited by small sample sizes.^5,6 Very few studies have used population-level data to describe the prevalence of OSA in pregnant individuals in recent times. In light of this, Frappaolo and colleagues designed this study to determine the trends in OSA diagnoses and to analyze the association between OSA and adverse pregnancy and neonatal outcomes during delivery hospitalizations in the United States.⁷

This study had a cross-sectional design using data from the National Inpatient Sample (NIS). The NIS is a 20% stratified sample of all delivery hospitalizations and discharges from U.S. acute care hospitals. The database is managed by the Agency for Healthcare Research and Quality. The sample reflects 97% of the U.S. population and all NIS admissions are fully de-identified. Using the International Classification of Diseases, Ninth Revision (ICD-9) and 10th Revision (ICD-10) codes, the authors included all pregnant persons between 15 and 45 years of age who were hospitalized with OSA between 2000-2019 in the United States captured within the NIS. The primary outcome of interest was OSA prevalence and trend during delivery hospitalization (2000-2019). Secondary outcomes were adverse maternal and fetal outcomes in pregnant individuals with OSA (compared to pregnant individuals without OSA). These secondary outcomes evaluated include peripartum hysterectomy, acute respiratory distress syndrome (ARDS), hypertensive disorders of pregnancy, need for mechanical ventilation or tracheostomy, cardiac failure/pulmonary edema, preterm birth, and stillbirth.

Demographics and maternal outcomes were analyzed using standard statistical tests. To calculate the trend of OSA during the study period (2000-2019), trend analyses were done on the proportion of deliveries by year with an OSA diagnosis using the average annual percentage change (AAPC). Multivariable regression models accounting for potential confounders were created for the outcomes and were adjusted for demographic, clinical, and obstetrical covariates. Unadjusted odds ratios (ORs) and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were used as measures of association.

From 2000 to 2019, 176,753,013 delivery hospitalizations were recorded, of which 54,238 (0.07%) had a diagnosis of OSA. During the study period, the prevalence of OSA during delivery hospitalizations increased from 0.4 to 20.5 cases/10,000 delivery hospitalizations (AAPC, 20.6%; 95% CI, 19.1 to 22.2) between 2000-2019. The prevalence of obesity also increased from 0.5% to 9.8% between 2000-2019. Adverse obstetric outcomes were greater in pregnant individuals with OSA compared to those without OSA. These include risks for mechanical ventilation or tracheostomy (aOR, 21.9; 95% CI, 18.0 to 26.7; P < 0.05), ARDS (aOR, 5.9; 95% CI, 5.4 to 6.5; P < 0.05), hypertensive disorders of pregnancy (aOR, 1.6; 95% CI, 1.6 to 1.7; P < 0.05), peripartum hysterectomy (aOR, 1.66; 95% CI, 1.23 to 2.23; P < 0.05), acute heart failure/pulmonary edema (aOR, 3.71; 95% CI, 2.93 to 4.71; P < 0.05), preterm birth (aOR, 1.2; 95% CI, 1.1 to 1.2; P < 0.05), and stillbirth (aOR, 1.2; 95% CI, 1.0 to 1.4; P < 0.05) after accounting for obesity, demographics, and hospital characteristics.

COMMENTARY

Over the course of 19 years (2000-2019), Frappaolo and colleagues demonstrated that OSA diagnoses at delivery hospitalization increased greater than 50-fold (0.4 to
20.5 cases/10,000 deliveries).⁷ In line with earlier research, the authors also demonstrated that hospitalizations for OSA were linked to advanced maternal age, maternal obesity, asthma, chronic hypertension, and pregestational diabetes mellitus. The authors demonstrated that there was a rise in the risk for peripartum hysterectomy, ARDS, heart failure/pulmonary edema, mechanical ventilation or tracheostomy, hypertensive disorders of pregnancy, preterm birth, and stillbirth between 2000 and 2019. The authors did observe, however, that their findings could have been limited by their use of administrative hospital discharge data, which could have been inaccurate because of under-ascertainment and misclassification. This is compounded by the absence of laboratory evidence that could confirm or refine diagnoses, such as OSA severity.

The gold standard for the diagnosis of OSA is an overnight in-laboratory sleep study polysomnogram (PSG).^1-3 During a sleep study, the PSG monitors, observes, and records numerous bodily functions that take place while the pregnant individual is asleep, including maternal heart rate, breathing, leg movements, and serum oxygen concentration. These are used to establish a diagnosis and, subsequently, to determine the next stages of treatment. Usually, a single night PSG is sufficient to assess whether OSA is present and how severe the problem is.

The apnea-hypopnea index (AHI) measures the extent of OSA and is used to classify the severity of OSA as normal (AHI of < 5 events/hour), mild OSA (AHI of 5-14 events/hour), moderate OSA (AHI of 15-29 events/hour), and severe OSA (AHI of ≥ 30 events/hour).^1,8 Pregnant individuals tend to have a higher AHI score compared to nonpregnant individuals (attributed to physiological changes that occur during pregnancy), but variations in laboratory diagnoses, differences in OSA screening questionnaires, and interscorer reliability also might potentially affect AHI scoring in pregnant individuals.^2,3,6

Early diagnosis of OSA during pregnancy has been demonstrated to be beneficial in the short term (reduction in the risk of hypertension, diabetes) and long term (reduction in the risk of renal and cardiovascular disease).^2,3 Treatment of OSA in pregnancy involves a multidisciplinary approach with OB/GYNs, sleep medicine specialists, and obstetric anesthesia. Management involves behavior modification (avoiding alcohol, anxiolytics, continuous opioid infusions, and sleep aid medications such as melatonin during pregnancy); patient education, such as proper sleeping hygiene; and the use of positive airway pressure (PAP) therapy. The same indications for PAP therapy in nonpregnant individuals (moderate to severe OSA, mild OSA with persistently low partial pressure of oxygen) also apply to pregnant people. However, auto-adjusting positive airway pressure (APAP) is preferred to continuous positive airway pressure (CPAP) in pregnant individuals with mild OSA who develop adverse pregnancy outcomes.⁹

Although there are no particular recommendations for screening or treating OSA during pregnancy by the American College of Obstetricians and Gynecologists, the American Society of Anesthesiologists (ASA), the Society for Obstetric Anesthesia, and the American Society for Sleep Medicine practice guidelines all recommend treatment of OSA during pregnancy, including an Anesthesiology consultation for airway examination and discussion of other intraoperative and peripartum complications in advance of delivery.^10-12 According to the ASA guideline, postoperative continuous pulse oximetry monitoring is advised for patients with known or suspected OSA.

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