Obstructive Sleep Apnea During Pregnancy

by Snigdhasmrithi Pusalavidyasagar, MD, FAASM

The prevalence of obstructive sleep apnea (OSA) during pregnancy is increasing worldwide. Pre-pregnancy obesity and the gestational weight gain increase the risk for OSA in pregnant women. In a recent meta-analysis, the estimated prevalence of OSA in pregnant women was 15%.¹ Pregnancy associated hormonal, physiological, and physical changes can all impact OSA. In a large cohort study using level 3 home sleep apnea testing, the prevalence of OSA increased from 3.6% in early pregnancy to 8.3% in mid-pregnancy.² A prospective study of 105 pregnant patients who completed polysomnography showed an increase in the prevalence of OSA from 10.5% in the first trimester to 26.7% in the third trimester.³ Despite the increasing prevalence, OSA during pregnancy is underdiagnosed due to barriers in identifying OSA.⁴ Sensitivity and specificity of the screening tools (Berlin questionnaire, Epworth Sleepiness Scale, and STOP-BANG) are suboptimal for pregnant women.⁵ Variables such as advanced maternal age, higher BMI, and frequent snoring can be used to predict OSA.⁶

OSA involves repetitive episodes of complete and partial upper airway obstruction, with intermittent hypoxemia/reoxygenation, causing sleep fragmentation, oxidative stress, increase in sympathetic activity, and endothelial dysfunction. All these factors increase risk for cardiovascular disease and can adversely impact maternal and fetal health. Hypertensive disorders of pregnancy (gestational hypertension, chronic hypertension, pre-eclampsia, and eclampsia), cardiomyopathy, gestational diabetes, and preterm delivery are maternal complications associated with OSA.⁷ Moderate to severe OSA is one of the risk factors for maternal cardiovascular disease. OSA has been shown as a risk factor for anesthesia-related maternal complications.⁸ Delivery rates by cesarean section are higher in pregnant patients with OSA compared to pregnant patients without OSA.⁹ OSA during pregnancy has been associated with growth retardation, pre-term birth, congenital anomalies, and small for gestational age.¹⁰

There are no current guidelines from the American Academy of Sleep Medicine for optimal timing of screening for OSA and management of OSA during pregnancy. Some researchers recommend prenatal OSA screening between 12 and 18 weeks. Facco and colleagues found a dose response between AHI severity and cardiometabolic risk at both early and mid-pregnancy indicating that OSA evaluation should be considered as early as the first trimester.¹¹ Women with suspected OSA during pregnancy should be referred to a sleep clinic for further evaluation and management. While polysomnography (PSG) remains the gold standard test for diagnosing OSA, testing is expensive, and scheduling can be delayed in some centers due to capacity and demand. Home sleep apnea testing (HSAT) is convenient, less expensive and can be helpful in diagnosing OSA in pregnant women, who are at moderate to high risk.¹² If the HSAT does not show evidence of OSA, PSG must be considered in pregnant women with high clinical suspicion.

Continuous positive airway pressure (CPAP) is the best treatment option for OSA during pregnancy and is safe. Women with a history of previously diagnosed OSA managed with CPAP should continue CPAP therapy during their pregnancy. Auto titrating CPAP therapy is more practical and helpful for treating OSA during pregnancy compared to CPAP with fixed pressure settings, since the severity of the OSA is subject to increase as the pregnancy progresses with gradual weight gain and hormonal changes.¹³ Close follow up after initiating CPAP therapy is important to assess the adherence to treatment. CPAP therapy has been shown to be helpful in specific high-risk obstetric populations. CPAP treated OSA women had lower incidence of severe forms of hypertensive disorders of pregnancy.¹⁴ Oral appliance therapy is often not practical for OSA during pregnancy, because it can take a few months to achieve adequate adjustment of the appliance to control the OSA.

OSA can persist in some women who do not return to their pre-pregnancy weight. CPAP therapy should continue until their BMI returns to 10% to 15% of their baseline BMI. A prospective observational study by Street and colleagues identified gestational OSA continued 2-3 months after delivery and estimated postpartum OSA prevalence at 20% at 6-8 months after delivery.¹⁵ Given the continuation of OSA in a subset of this population and the potential adverse effects to women’s overall health, effective OSA screening and treatment modalities for postpartum women need to be identified. OSA can be associated with postpartum depression (PPD). In a prospective study, Bourjeily et al showed a higher prevalence of PPD in women with OSA.¹⁶ Sleep apnea treatment can improve depression in postpartum women. However, adherence to CPAP therapy can be difficult for some new mothers attending to an infant. In these cases, positional therapy or mandibular advancement device may be considered. Further research is needed to develop screening tools and treatment guidelines for OSA during pregnancy and postpartum periods to improve both maternal and fetal outcomes.