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Sleep Apnea During Pregnancy: Everything You Need to Know
Pregnancy is a period of deep physiological change that can bring on or worsen sleep apnoea. The condition is often under-diagnosed in pregnant women, despite consequences that can be serious for both mother and baby. This guide sets out what is known.
Why does pregnancy increase the risk of sleep apnea?
Sleep apnoea is more common during pregnancy than was long believed. Several mechanisms contribute to that increased risk:
- Weight gain: normal gestational weight gain, 10 to 15 kg depending on the starting BMI, increases the fat mass around the neck and the pharynx. The upper airway becomes narrower as a result.
- Nasal congestion: pregnancy rhinitis, a hormonal nasal congestion, is very common and encourages mouth breathing, which in turn makes apnoeas worse.
- Hormonal changes: rising progesterone stimulates breathing, but nasal congestion and anatomical changes offset that protective effect.
- Gastro-oesophageal reflux: common in pregnancy, it can increase airway inflammation.
- Sleeping position: lying on the back, hard to avoid late in pregnancy, makes apnoeas worse.
- Increased blood volume: it can cause swelling of the mucous membranes of the upper airway.
A meta-analysis of 33 studies puts the prevalence of sleep apnoea during pregnancy at 15 % (Sleep and Breathing, 2019). It rises clearly over the trimesters: around 10 % in the first, close to 27 % in the third. In women who are obese or who have pre-eclampsia, it is higher still.
Risk factors specific to pregnancy
- A high pre-pregnancy BMI (obesity)
- A multiple pregnancy (twins, triplets)
- Gestational hypertension
- Pre-eclampsia (high blood pressure with protein in the urine)
- Gestational diabetes
- Older maternal age (35 and above)
- A history of sleep apnoea or of snoring before the pregnancy
Consequences of untreated apnea during pregnancy
For the mother:
- Gestational hypertension and pre-eclampsia: sleep apnoea is strongly associated both with their onset and with their worsening. Pre-eclampsia is a serious complication that can force an early delivery.
- Gestational diabetes: episodes of night-time hypoxia increase insulin resistance and the risk of gestational diabetes.
- Extreme tiredness: pregnancy is already tiring; untreated apnoea makes that tiredness far worse.
- Perinatal depression: sleep disorders are a risk factor for antenatal and postnatal depression.
- Higher cardiovascular risk: arrhythmias, strain on the heart.
For the baby:
- Foetal growth restriction: repeated episodes of night-time hypoxia can reduce the oxygen reaching the foetus and slow its growth.
- Preterm birth: the risk of an early delivery is increased in women with severe untreated apnoea.
- Low birth weight: correlated with episodes of chronic hypoxia.
- Caesarean delivery: rates are higher in women with sleep apnoea.
CPAP therapy during pregnancy
CPAP is the reference treatment for obstructive sleep apnoea and it is safe throughout pregnancy. It is recommended for pregnant women with moderate to severe apnoea, or with mild apnoea together with pregnancy complications (pre-eclampsia, gestational diabetes).
The benefits of CPAP during pregnancy include:
- Fewer episodes of night-time hypoxia, a direct benefit for foetal oxygenation
- Better control of gestational blood pressure
- Improved sleep quality and less daytime tiredness
- A possible reduction in the risk of pre-eclampsia, with studies still under way
Sleep positioning and apnea
Sleeping position plays an important part in apnoeas during pregnancy. Lying on your back makes apnoeas worse. The weight of the uterus compresses the inferior vena cava, and the base of the tongue blocks the airway more easily.
Recommendations for positioning:
- Sleep on your left side as a priority: this is the position that best supports blood flow between the uterus and the placenta and that reduces apnoeas. The left side is preferred because it frees the inferior vena cava, which runs to the right of the spine and which the weight of the uterus compresses as soon as you lie on your back or on your right side.
- Pregnancy pillow: C-shaped or U-shaped pillows help hold the side position all night and avoid rolling over unintentionally.
- The semi-reclined position, with the upper body raised: it can reduce snoring and reflux, but it is hard to hold for a whole night. It complements sleeping on your side, it does not replace it.
After delivery
Sleep apnoea that is specifically linked to the pregnancy can improve markedly after delivery, thanks to weight loss and to less congestion. However:
- Women who had apnoea before the pregnancy must continue their treatment.
- A reassessment (polygraphy or PSG) is recommended 3 to 6 months after delivery, to determine whether CPAP is still needed.
- Breastfeeding is not a contraindication to CPAP.
CPAP devices available at VivaRespire
If your doctor recommends a CPAP during or after your pregnancy, VivaRespire lets you buy your device directly and own it. For the details of the INAMI/RIZIV convention: CPAP reimbursement in Belgium.
See our Auto CPAP devices and CPAP masks.
Frequently asked questions about sleep apnea and pregnancy
Yes. Pregnancy combines several factors that increase apnea risk: weight gain, hormonal nasal congestion, gastroesophageal reflux, forced supine position late in pregnancy, increased blood volume with mucosal oedema. A meta-analysis of 33 studies puts the prevalence at 15% in pregnancy (Sleep and Breathing, 2019), rising markedly from one trimester to the next: around 10% in the first, close to 27% in the third. In obese women or those with pre-eclampsia it is higher still. Consult a sleep physician for an individual diagnosis.
Repeated episodes of nocturnal hypoxia can affect fetal oxygenation. Documented risks include: fetal growth restriction, increased risk of prematurity, low birth weight, and higher cesarean section rate. Maternal apnea is also associated with increased risk of gestational hypertension and pre-eclampsia, complications that can themselves affect the baby. This is why screening and treatment during pregnancy are important.
Yes. CPAP is considered safe throughout pregnancy - it only delivers positive air pressure and has no pharmacological effect on the fetus. It is recommended in pregnant women with moderate to severe apnea, or with mild apnea associated with gestational complications (pre-eclampsia, gestational diabetes). The required pressure may increase over the trimesters due to weight gain - regular follow-up with your sleep physician is recommended.
Yes, it is one of the simplest levers. The supine position worsens apnea and compresses the inferior vena cava (bad for uteroplacental circulation). It is advised to sleep on the left side preferentially, which optimises blood circulation. A C-shaped or U-shaped pregnancy pillow helps maintain lateral position throughout the night. A semi-reclined position with the upper body raised can help against snoring and reflux, but it does not replace sleeping on your side.
Apnea specifically related to pregnancy (with no prior history) can improve significantly after childbirth, alongside weight loss and resolution of congestion. Women with pre-existing apnea must continue treatment. A reassessment by polygraphy or PSG is recommended 3 to 6 months after delivery to determine whether CPAP is still needed. Breastfeeding is not a contraindication.
Report any loud snoring, excessive sleepiness or breathing pauses observed by your partner to your gynaecologist or midwife. On referral, you can be sent to a sleep centre for nocturnal respiratory polygraphy (generally at home). The diagnosis is rapid and the test is safe for the baby. If apnea is confirmed, CPAP treatment can be started without delay. Consult a sleep physician for an individual diagnosis.
Yes, the link is established. Nocturnal hypoxia episodes and sleep fragmentation increase insulin resistance, which is already physiologically heightened in pregnancy. This promotes the onset of gestational diabetes. Conversely, gestational diabetes can worsen apnea risk through weight gain and metabolic changes. If you have gestational diabetes and snore, discuss this with your gynaecologist: apnea screening may be relevant.