Obstructive Sleep Apnea (OSA) involves repeated episodes where the upper airway partially or completely collapses, causing pauses in breathing that last ten seconds or longer. Pregnancy can significantly increase the likelihood of developing or worsening sleep apnea due to profound physiological changes in the body. While less common in women of childbearing age, the prevalence of OSA can rise sharply as gestation advances, affecting up to 27% of high-risk pregnant individuals by the third trimester. This temporary or newly induced condition warrants attention because it can introduce significant health concerns for both the expecting parent and the developing fetus.
The Physiological Links
The increased risk of sleep apnea during pregnancy is rooted in hormonal shifts and mechanical pressures. Elevated levels of hormones like estrogen cause the mucous membranes lining the nasal passages and throat to swell. This mucosal edema narrows the upper airway, leading to congestion and making the airway more susceptible to collapse during sleep. Progesterone also stimulates the respiratory drive, but this enhanced breathing effort can sometimes create a “vacuum effect” that contributes to airway instability and collapse.
Weight gain, which is a normal part of gestation, contributes to the accumulation of soft tissue around the neck and throat, adding external pressure on the upper airway. Furthermore, the growing uterus pushes upward on the diaphragm, especially when the individual is lying on their back. This mechanical compression reduces the functional residual capacity, which in turn increases the collapsibility of the smaller airways.
Fluid retention (edema) is common in pregnancy and affects the tissues of the throat. The increased fluid volume in the body can lead to upper airway congestion and pharyngeal narrowing. These combined hormonal, mechanical, and fluid-related changes create a physical environment that predisposes the pregnant body to obstructive sleep apnea.
Risks to Mother and Baby
The repeated episodes of oxygen deprivation and sleep fragmentation characteristic of untreated sleep apnea pose risks for the pregnant individual. One significant maternal risk is the increased chance of developing gestational hypertension and preeclampsia, a condition involving high blood pressure and organ damage. The intermittent drops in blood oxygen levels associated with OSA are thought to trigger oxidative stress and increased sympathetic nervous system activity, which are underlying factors in these hypertensive disorders.
The condition is also associated with an elevated risk of gestational diabetes, reflecting a link between poor sleep quality, inflammation, and insulin resistance. Individuals with untreated sleep apnea may also face higher rates of operative delivery, including unplanned cesarean sections, and prolonged labor.
For the developing fetus, untreated maternal sleep apnea can restrict growth and development. The recurring periods of low oxygen saturation can lead to intermittent fetal hypoxia, which impairs the delivery of necessary oxygen and nutrients through the placenta. Consequences of this impaired environment include:
- Increased risk of preterm birth.
- Low birth weight and fetal growth restriction.
- Higher chance of requiring admission to the neonatal intensive care unit (NICU).
- Exhibiting low Apgar scores immediately after birth.
Recognizing and Diagnosing
Recognizing sleep apnea during pregnancy can be challenging because some symptoms overlap with common pregnancy discomforts. The most telling sign is loud, habitual snoring, particularly if it is a new development or has worsened since becoming pregnant. Other key symptoms include witnessed apneas (pauses in breathing observed by a partner) or gasping and choking sounds during sleep.
Excessive daytime fatigue that goes beyond the usual tiredness of pregnancy, morning headaches, and non-refreshing sleep should raise suspicion. Since many pregnant individuals experience fatigue and disrupted sleep, objective testing is often necessary for an accurate diagnosis. The definitive diagnostic test is Polysomnography (PSG), which is typically performed in a sleep lab.
This overnight study safely monitors breathing patterns, heart rate, blood oxygen levels, and brain activity to quantify the severity of the sleep disorder. Healthcare providers should consider screening for sleep apnea, especially in individuals with risk factors like pre-pregnancy obesity, chronic hypertension, or gestational diabetes. Early identification is helpful for managing the condition and mitigating potential risks.
Safe Management Strategies
The treatment for obstructive sleep apnea during pregnancy is Continuous Positive Airway Pressure (CPAP) therapy. This involves wearing a mask over the nose or mouth while sleeping, which delivers a constant stream of pressurized air to keep the airway open. CPAP is non-invasive and has been shown to reduce the risk of hypertensive disorders like preeclampsia when used consistently.
Positional therapy is another simple yet effective management strategy, as sleep apnea often worsens when lying on the back. Healthcare providers recommend sleeping on the side, ideally the left side, which also helps optimize blood flow to the fetus. Elevating the head of the bed can also help reduce airway congestion and improve breathing mechanics.
Maintaining a healthy weight gain pattern, as advised by a physician, supports overall maternal health and can help minimize added pressure on the airways. After delivery, the sleep apnea that developed during pregnancy often resolves, which is likely due to the reversal of hormonal and mechanical changes. However, approximately half of those diagnosed during pregnancy may continue to have the condition, making a follow-up sleep study a few months postpartum a necessary step to confirm resolution.