Sleep apnea is a disorder marked by repeated interruptions in breathing during sleep, where the airway either partially closes or completely collapses. This condition, known as Obstructive Sleep Apnea (OSA), is a recognized health concern for all individuals, but pregnancy significantly increases the risk of developing or worsening it due to profound physiological and hormonal shifts. The prevalence of OSA in pregnant individuals is notably higher than in non-pregnant women of similar age, with estimates suggesting that up to 27% of women in the third trimester may be affected. Recognizing and addressing sleep apnea when pregnant is important because it can lead to serious health complications for both the mother and the developing fetus.
Physiological Changes and Warning Signs
The unique physiological state of pregnancy creates several mechanisms that predispose an individual to obstructive sleep apnea. Hormonal changes play a large role, as increased levels of estrogen and progesterone cause the mucous membranes lining the nose and throat to swell, leading to nasal congestion and narrowing of the upper airway. This swelling, known as pregnancy rhinitis, makes the airway more susceptible to collapse during sleep when muscle tone naturally relaxes.
Physical changes further compound this issue, particularly in the later stages of gestation. As the uterus expands, it pushes the diaphragm upward, which reduces the lung’s functional capacity by as much as 20%. This mechanical restriction, combined with the body’s increased oxygen consumption, means the respiratory system is under greater strain, especially when lying down.
The most common signs of sleep apnea are often noticed by a sleeping partner, such as loud, persistent snoring or observed episodes of gasping, snorting, or choking during sleep. Although some fatigue is expected during pregnancy, excessive daytime sleepiness (hypersomnia) that is not relieved by rest can be a warning sign. Morning headaches, forgetfulness, and difficulty concentrating are also subtle indicators that the quality of nighttime breathing is compromised.
Maternal and Fetal Health Consequences
Untreated obstructive sleep apnea during pregnancy is linked to a higher incidence of serious maternal health complications. The repeated cycles of oxygen desaturation and reoxygenation place stress on the cardiovascular system, increasing sympathetic nervous system activity and systemic inflammation. This contributes to an elevated risk of developing hypertensive disorders of pregnancy.
Individuals with OSA face an increased risk of gestational hypertension and preeclampsia, a condition characterized by high blood pressure and signs of damage to another organ system, often the kidneys. The metabolic stress from sleep fragmentation and intermittent hypoxia also raises the likelihood of developing gestational diabetes mellitus.
When maternal oxygen levels drop repeatedly, the fetus’s oxygen supply is reduced, which can negatively impact development. Maternal sleep apnea is associated with adverse fetal outcomes, including fetal growth restriction (FGR), where the baby does not grow to its expected size. Reduced oxygen and nutrient exchange across the placenta can also lead to an increased risk of preterm birth. Additionally, these risks may contribute to a higher rate of cesarean delivery, as the mother’s and baby’s health may necessitate surgical intervention.
Identifying Sleep Apnea
Identifying sleep apnea during pregnancy often begins with screening tools due to the overlapping nature of OSA symptoms and common pregnancy discomforts. Healthcare providers may use questionnaires like the STOP-BANG tool to assess risk factors such as loud snoring, tiredness, observed apneas, and high blood pressure. Screening is suggested for those with pre-existing conditions like obesity or hypertension, or those reporting new or worsening symptoms.
While screening questionnaires can raise suspicion, the definitive diagnosis of Obstructive Sleep Apnea relies on a formal sleep study, known as polysomnography (PSG). This test requires the individual to sleep overnight, usually in a specialized lab, while sensors monitor breathing, oxygen saturation, and sleep stages.
Sometimes, a home sleep apnea test may be used initially, which measures breathing and oxygen levels in the patient’s home environment. However, in pregnant individuals, in-lab polysomnography is often preferred for a more comprehensive and accurate assessment. The diagnosis is confirmed when the Apnea-Hypopnea Index (AHI)—the number of breathing pauses or shallow breathing events per hour—reaches five or more events.
Treatment Options and Monitoring
The primary intervention for managing obstructive sleep apnea in pregnant individuals is Continuous Positive Airway Pressure (CPAP) therapy. CPAP is safe for use throughout pregnancy because it is a mechanical, non-invasive treatment that does not involve medication. The device delivers pressurized air through a mask worn during sleep, which keeps the upper airway open, preventing collapse.
Consistent CPAP use is important, as it helps maintain stable oxygen levels for both the mother and the fetus, mitigating the risks associated with intermittent hypoxia. CPAP treatment can reduce the risk of developing gestational hypertension and preeclampsia in affected individuals. Improving sleep quality also reduces daytime fatigue and improves overall well-being.
Ancillary strategies complement CPAP therapy, including positional adjustments to improve airflow. Sleeping on the side, particularly the left side, can help alleviate pressure on the major blood vessels and the airway. Weight management, if medically appropriate and supervised, may also be discussed. Once sleep apnea is diagnosed, continuous monitoring of maternal blood pressure and fetal growth is often incorporated into prenatal care to ensure the best possible outcomes.