About one in three pregnant women snore, and for most of them, snoring is something that started only after they became pregnant. In a study of over 1,700 pregnant women, 25% reported pregnancy-onset snoring, while only 9% had snored before conceiving. The causes are a combination of hormonal shifts, increased blood volume, and physical changes to the airway and chest cavity that all converge as pregnancy progresses.
Hormones Swell Your Nasal Passages
Rising estrogen levels during pregnancy trigger a chain reaction inside the nose. Estrogen increases parasympathetic nerve activity, which dilates blood vessels in the nasal lining and causes the tissue to swell. At the same time, estrogen ramps up protein and mucus production in the nasal membranes, thickening secretions and slowing the nose’s natural self-clearing process. The result is chronic stuffiness that has nothing to do with a cold or allergies.
This condition, known as pregnancy rhinitis, affects roughly 20 to 30% of pregnant women and can persist for weeks or months. When nasal passages narrow, air has to squeeze through a tighter space, and the soft tissues of the throat vibrate more easily. That vibration is snoring. For many women it appears in the second trimester and worsens steadily through the third.
More Blood, More Congestion
Blood volume increases by about 40 to 50% during pregnancy to support the growing baby. That extra blood flow reaches the nasal veins too, enlarging them and further crowding an already swollen airway. Think of it as adding more water to an already full sponge: the nasal tissues become engorged, and breathing through the nose gets harder, especially when lying down. Gravity pulls extra fluid into the head and neck at night, making congestion and snoring worse during sleep.
A Growing Belly Changes How You Breathe
As the uterus expands, it pushes the diaphragm upward by 4 to 5 centimeters by the end of pregnancy. This shift reduces the amount of air your lungs can hold at rest, particularly from the end of the second trimester onward. Although total lung capacity stays roughly the same (the rib cage widens to compensate), the reserve air you normally keep in your lungs after a relaxed exhale drops significantly.
With less reserve air and swollen upper airways, the body has to work harder to move air in and out. That increased effort, combined with the narrowed nasal passages, makes the soft palate and surrounding tissue more prone to vibrating during sleep. Weight gain during pregnancy adds to this: extra tissue around the neck and throat further narrows the airway.
When Snoring Signals Something More Serious
Most pregnancy snoring is harmless, but new-onset snoring is linked to higher risks for two major pregnancy complications. Women who begin snoring during pregnancy have roughly 2.4 times the odds of developing gestational hypertension (high blood pressure) and about 1.6 times the odds of preeclampsia compared to non-snorers, even after accounting for other risk factors. Women who snored before pregnancy did not show the same increased risk, suggesting that the new snoring itself may reflect underlying vascular changes that matter.
Sleep-disordered breathing during pregnancy is also tied to gestational diabetes. A large meta-analysis pooling nearly 10,000 pregnant women found that those with disordered breathing during sleep had roughly two to three times the odds of developing gestational diabetes after adjusting for body weight. Habitual snoring alone, without a formal sleep apnea diagnosis, was enough to raise the risk.
The concern is that repeated partial airway obstruction during sleep can lower blood oxygen levels, trigger stress hormones, and raise blood pressure. Over time, these disruptions may contribute to the inflammation and insulin resistance that underlie preeclampsia and gestational diabetes.
Snoring vs. Sleep Apnea in Pregnancy
Not all snoring means sleep apnea, but distinguishing the two during pregnancy is tricky. Standard screening tools perform poorly in pregnant women because so many pregnancy symptoms overlap with sleep apnea symptoms. Fatigue, poor sleep quality, and daytime sleepiness are nearly universal in late pregnancy, so they lose their value as warning signs. In one study of obese pregnant women, 35% reported significant fatigue and 47% had poor sleep quality regardless of whether they had sleep apnea.
Red flags that suggest something beyond simple snoring include gasping or choking during sleep (often noticed by a partner), pauses in breathing, waking with headaches, and excessive daytime sleepiness that goes beyond normal pregnancy tiredness. Women with higher body weight, high blood pressure, and signs of insulin resistance before or during pregnancy appear to be at the greatest risk for actual sleep apnea rather than just snoring.
What Actually Helps
Sleeping on your side, particularly the left side, is one of the most effective and simplest changes you can make. Side sleeping keeps the airway more open than back sleeping and also improves blood flow to the baby and kidneys. Placing a pillow between your knees and another under your belly can create a comfortable tilt that keeps you from rolling onto your back during the night. A pillow behind your back adds extra insurance.
Elevating the head of the bed by a few inches (using a wedge pillow or blocks under the headframe) can reduce the amount of fluid that pools in the nasal passages overnight. A cool-mist humidifier in the bedroom helps keep nasal membranes from drying out and cracking, which can worsen congestion.
Adhesive nasal strips are popular, but the evidence for them in pregnancy is weak. A study specifically testing nasal dilator strips in pregnant women found they did not significantly improve measures of sleep-disordered breathing. They may offer mild comfort if your main issue is nasal congestion, but they are not a reliable solution for snoring itself.
Saline nasal rinses or sprays are generally considered safe during pregnancy and can temporarily clear thick mucus. Avoiding known nasal irritants, staying hydrated, and keeping weight gain within recommended ranges all help reduce the severity of snoring. If snoring is loud, frequent, or accompanied by breathing pauses, a sleep study can determine whether treatment for sleep apnea is needed.
Snoring Usually Stops After Delivery
For the majority of women, pregnancy-onset snoring resolves within a few weeks of giving birth. As estrogen levels drop, blood volume returns to normal, and the diaphragm moves back into position, the airway opens up again. Women who snored before pregnancy are more likely to continue afterward. If snoring persists beyond a couple of months postpartum, it may be worth investigating independently of pregnancy, since it could indicate sleep apnea unrelated to the hormonal and physical changes of carrying a baby.