Are you snoring during your pregnancy or know someone who is?

Are you tired or frustrated by the snoring?

We agree that this is a problem and we would like to help provide more information.

Snoring is common during pregnancy, especially during the third trimester.[1]

This snoring during pregnancy guide was created over three months with the intent of being a helpful, yet comprehensive resource for women who are pregnant and snore.

This guide may also be helpful for the snorer’s bed partner and for the snorer’s family.

Frequently asked questions and questions posted on the internet were collected and answered.

This information guide helps explain why women snore during pregnancy, what problems the snoring can cause and what can be done to help improve the snoring.

Additionally, references and resources are provided to help provide information for snoring during pregnancy.

Weight gain during pregnancy. Note that the neck is larger, and the inside portion of the throat is also larger, which makes the airway smaller on the inside. BladeMD.com
Weight gain during pregnancy. Note that the neck is larger, and the inside portion of the throat is also larger, which makes the airway smaller on the inside.

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Summary for snoring during pregnancy:

Snoring during pregnancy can be bothersome to the bed partner, and can be a sign of obstructive sleep apnea (OSA). Although a relatively low percentage of women snore, it is more common during pregnancy as women gain weight and their airways narrow. Snoring is due to the vibration of soft tissues in the throat (soft palate and uvula in most cases). A pregnant woman who snores and has pauses in breathing could have OSA. Snoring can be a sign of obstructive sleep apnea, which is a disorder in which patients have decreased airflow or no airflow for 10 seconds or more per episode on a repeated basis during sleep. A sleep study could be ordered to evaluate for snoring and OSA. Treatment is then started based on the patient’s symptoms and the severity of OSA.

If the snoring is concerning at all, then a visit to a healthcare provider is recommended.

Background information about snoring during pregnancy:

Why do pregnant women snore?

Five common reasons for snoring during pregnancy include:

  • Weight gain (fat can deposit into the tongue and throat),
  • Hormone changes (hormones can cause increased nasal congestion),
  • Fluid from the legs can shift to the neck and upper airway while lying down,
  • The abdomen and uterus enlarge and press against the diaphragm, and
  • The overall increase in body mass can cause a smaller space for air to flow from the nose or mouth or throat into the lungs.

Is snoring caused by the vibration of the soft tissues of the upper airway?

Yes, snoring is due to the back and forth movement (vibration) of the soft tissues of the upper airway during sleep.

The most common locations for the vibration includes the soft palate and uvula (tissue that hangs down from the soft palate).[2]

Other tissues that can vibrate include the tonsils, the tongue, the epiglottis (the flap that covers the upper airway when you eat, drink or swallow to protect you from choking) and the supraglottis (soft tissue just above the vocal cords).[2]

It has been demonstrated that even in a non-pregnant woman, sleep-disordered breathing (such as snoring and obstructive sleep apnea) has been associated with high blood pressure, diabetes and cardiovascular disease.[3]

Can pregnancy decrease the size of the upper airway?

Yes, weight gain during pregnancy causes an increase in the body mass index, and the increased body mass can contribute to a smaller upper airway.

If the weight gain includes an increase in the body fat, then the fat storage also can deposit into the throat and tongue, again narrowing the upper airway.

An increase in the size of the neck and mass within the neck can also hypothetically contribute to narrowing the upper airway when she lies on her back as the tissue would push against the front of the neck, and this could potentially make snoring worse.

How common is snoring during pregnancy?

Snoring during pregnancy in early pregnancy (before 20 weeks gestation):

A large study of 1,303 pregnant women found that 7.3% had habitual snoring in early pregnancy.[4]

How does snoring compare in non-pregnant women vs. women in the third trimester of pregnancy?

Another study found that 4% of non-pregnant women snored, while 14% of women in the third trimester of pregnancy snored.[5]

Snoring during pregnancy in the first vs. the second vs. the third trimester:

In a study evaluating snoring during pregnancy, 18.1% of women snored in the first trimester and 25.7%of women snored in the late second trimester and early third trimester. [6]

Are obese women at a higher risk of having sleep-disordered breathing compared to non-obese women?

Yes. Obese women gain weight and mass during their pregnancy, which makes an already narrow airway even narrower as the pregnancy progresses.

A study evaluating obese women and non-obese women found that obese women gained on average 13 kg, while the control women gained 16 kg.[7]

Despite the non-obese women gaining more weight (relatively speaking), when compared to obese women, the non-obese women had significantly less snoring (1% of the night compared to 32% of the night) and had fewer oxygen drops.[7]

Information about diagnosing snoring during pregnancy:

Could snoring during pregnancy be a sign of obstructive sleep apnea?

Yes. Snoring can be present during pregnancy with or without obstructive sleep apnea. If the snoring is nightly and she is awakening throughout the night with choking, gasping or there are pauses in breathing, then there is an increased amount of upper airway blockage or obstruction.

The increased upper airway obstruction could potentially reduce the oxygen that is delivered to the woman and her unborn child when she sleeps.

What is obstructive sleep apnea?

Obstructive sleep apnea is when there is obstruction or blockage of airflow during sleep that can cause the brain to have to repeatedly wake up at night (also known as brain arousal).

These blockages are counted if they last 10 seconds and are associated with a moderate decrease in airflow (hypopneas) or a severe decrease in airflow (apneas).

Upper airway obstruction at the level of the soft palate and the tongue. Note that since the airflow is blocked, the oxygen cannot get into the airway and carbon dioxide cannot leave. The light blue arrow points to the obstructed palate and the obstructed tongue. CamachoMD.com
Upper airway obstruction at the level of the soft palate and the tongue. Note that since the airflow is blocked, the oxygen cannot get into the airway and carbon dioxide cannot leave. The light blue arrow points to the obstructed palate and the obstructed tongue.

What is a respiratory effort related arousal (RERA)?

A respiratory effort related arousal (RERA) is when there is a respiratory event that doesn’t meet the criteria for a hypopnea or an apnea but is associated with brain arousal (brain awakens, but the patient doesn’t necessarily need to awaken to the point of alertness).

Sleep-disordered breathing is a spectrum, with very quiet snoring on one end of the spectrum and severe, repeated blockage of the airway on the other end of the spectrum (severe obstructive sleep apnea).

What are the severity categories for normal breathing compared to obstructive sleep apnea?

  • Normal: 0 to <5 blockages per hour of sleep,
  • Mild: 5 to <15 blockages per hour of sleep,
  • Moderate: 15 to <30 blockages per hour of sleep; and
  • Severe: 30 or more blockages per hour of sleep

How do you treat obstructive sleep apnea?

Generally, obstructive sleep apnea is treated with CPAP (continuous positive airway pressure) machines. The machines blow air into the airway and CPAP masks commonly are in the form of nasal CPAP or full facemask CPAP.

Pregnant woman using CPAP to treat obstructive sleep apnea. The CPAP machine helps to eliminate the problems with snoring and obstructive sleep apnea. The breathing is now quiet. BladeMD.com
Pregnant woman using CPAP to treat obstructive sleep apnea. The CPAP machine helps to eliminate the problems with snoring and obstructive sleep apnea. The breathing is now quiet.

What are the two major categories for sleep studies?

  • A home sleep study, and
  • An in-lab sleep study.

What is a sleep study?

A sleep study is either done at home or in the sleep lab (monitored hotel room, university, or another building).

The goal of a sleep study is to see if there are problems or disorders during sleep to include problems with breathing (i.e. snoring and obstructive sleep apnea), sleepwalking, sleep talking, narcolepsy, seizures, leg movements, arm movements, sleep terrors or other disorders.

If you have obstructive sleep apnea, then the healthcare provider will likely order you a positive airway pressure device that can be used to treat obstructions.

Risk factors and causes for snoring during pregnancy:

How does a growing abdomen worsen snoring and obstructive sleep apnea during pregnancy?

The growing abdomen and uterus can put pressure on the diaphragm.

As the abdomen and uterus grow, there is an increase in the amount of pressure placed onto the diaphragm, thus there is a potential for the lungs to not get as much air as they normally do. This air restriction could hypothetically contribute to the obstruction of airflow during sleep.

How does leg swelling increase snoring and potentially worsen obstructive sleep apnea?

When humans lie down, there is a fluid shift from the legs to the neck and upper airway, known as a rostral fluid shift. Studies have demonstrated that the upper airway can narrow with fluid shifting and therefore there is a predisposition for snoring.[8]

So, it is logical that a woman with increased leg swelling can have an increase in a rostral fluid shift, which could narrow the upper airway and worsen snoring.

Is there a healthy way to manage weight gain during pregnancy?

Yes, a healthcare provider and dietician can help guide weight management during pregnancy.

There is a normal amount of expected weight gain throughout the pregnancy. If there is an excessive amount of weight gain, then the extra weight can potentially worsen snoring and breathing during sleep.

Because of the importance of providing key nutrients to the developing fetus, women should consult their healthcare provider and dietician if they plan to manage their weight.

Woman before pregnancy. BladeMD.com
Woman before pregnancy.
Pregnant woman after gaining weight. The upper airway becomes smaller as the neck becomes larger. BladeMD.com
Pregnant woman after gaining weight. The upper airway becomes smaller as the neck becomes larger.

Can a blocked nose cause snoring in pregnant women?

Yes, in some cases. Although the nose does not generally vibrate during sleep, it is known that hormone changes (such as estrogen, progesterone, and others) during pregnancy can increase nasal congestion and obstruction and that can contribute to snoring.[9]

The theory behind why nasal congestion can worsen snoring is that the smaller nasal airway causes the air coming into the nose to travel at a higher velocity and that causes the vibrations in the upper airway to increase and therefore the snoring sound increases.

Do some women snore only through their noses, but not through their mouths?

One study found that some patients snored exclusively during nasal breathing (patients had primary snoring or mild obstructive sleep apnea) and they had complaints of significant nasal obstruction and has swollen tissues in their nose (inferior turbinate hypertrophy).[10]

Does the nasal blockage go away after delivering the baby?

Generally, if the mother did not have nasal blockage or nasal congestion prior to the pregnancy, then yes, the nasal blockage can go away after delivering the baby. It may take a few weeks for the mother to have an improvement in nasal breathing.

Side effects and complications from snoring during pregnancy:

What are the effects of snoring on the mother and developing baby?

Is snoring during pregnancy harmful to the mother or baby?

The answer as to whether snoring during pregnancy is harmful depends on whether it is causing or worsening other problems such as sleepiness, high blood pressure, diabetes, insomnia or weight gain.

Snoring can be a sign of obstructive sleep apnea, which can cause many problems to include sleepiness, retention of carbon dioxide and a drop in oxygen throughout the night.

Snoring during pregnancy and medical problems:

According to a review of the literature and evaluation of the international data (a meta-analysis)[1], Dr. Li and colleagues evaluated and compared outcomes for women from three groups:

  • those who did not snore or have obstructive sleep apnea,
  • women with snoring alone (no obstructive sleep apnea), and
  • women with obstructive sleep apnea (blocked breathing during sleep) and found:

Women with snoring alone or obstructive sleep apnea (when compared to women without these disorders) had an increased risk of:

  • Gestational diabetes mellitus,
  • Pre-eclampsia, and
  • Pregnancy-induced high blood pressure.[1]

Women with snoring alone or obstructive sleep apnea (when compared to women without these disorders) have no significant differencein:

  • Birthweight,
  • Pre-term birth, and
  • APGAR scores at 5 minutes.[1]

A difference between women with snoring alone when compared to women who have obstructive sleep apnea is that the women with obstructive sleep apnea had an increased risk of pre-term birth.[1]

How does sleep-disordered breathing (snoring and obstructive sleep apnea) affect the developing baby?

The fetus receives oxygen and nutrients from his/her mother. Therefore, the oxygen and nutrients that the mother takes in will affect the fetus.

How does the fetus get oxygen and nutrients?

The mother’s uterus supplies blood and nutrients and hormones to the fetus through the placenta.

How does the mother’s breathing during sleep affect the fetus?

If a pregnant woman has obstructive sleep apnea and drops in her oxygen level, then this can lead to a lower oxygen level in the fetus.[3]

Additionally, during the obstructive breathing events, the mother can also retain carbon dioxide and this can cause increased carbon dioxide in the blood and this can lead to the fetus developing a lower blood pH (respiratory acidosis).[3]

It has been shown that decelerations of the fetal heart can occur during obstructive events when there is a decreased oxygen level.[3]

Does sleep-disordered breathing in the mother affect how a child is delivered?

A review[11] found that sleep-disordered breathing during pregnancy can affect the delivery of the baby.

Women with sleep-disordered breathing during pregnancy were:

  • Less likely to have a vaginal delivery,
  • At higher risk of having an assisted vaginal delivery,
  • At higher risk of having a cesarean delivery.

What is the relationship between snoring during pregnancy and high blood pressure (hypertension)?

High blood pressure during pregnancy is defined by having ≥140 millimeters of mercury for systolic blood pressure and having ≥90 millimeters of mercury for diastolic blood pressure.[12]

Frequent snoring (≥3 nights of snoring per week) has been associated with a two-fold increase in high blood pressure disorders of pregnancy.[12]

What is the relationship between snoring during pregnancy and diabetes?

It has been found that there is an association between habitual snoring during early pregnancy and the risk of:

  • Gestational diabetes, and
  • Impaired glucose tolerance.[13]

A study found that women who snored most of the time or all of the time had a 2.5-fold increase in the odds ratio for having gestational diabetes and a 2.1-fold increase in the odds ratio for having impaired glucose tolerance.[13]

Healthcare providers should perform glucose testing during the pregnancy, and they may select to monitor blood glucose levels on a scheduled basis and should notify the patient of the results, especially if the glucose elevated as this may lead to more testing.

How is an oral glucose tolerance test performed?

The Carpenter and Coustan criteria[14] is the commonly accepted standard for performing the oral glucose tolerance test. The testing includes the following[14]:

  • 1-hour, 50-gram oral glucose loading test is given for screening,
  • After the 1-hour oral glucose loading, a serum glucose value >200 mg/dL is considered positive for gestational diabetes  without the need for an oral glucose tolerance test,[15]
  • If the serum glucose value is 130-200 mg/dL, then: A 3-hour, 100-gram oral glucose tolerance test is given.

When the 3-hour, 100-gram oral glucose tolerance test is used, then two or more values meeting the following criteria are considered positive for gestational diabetes:

  • Fasting glucose >95 mg/dL, or
  • Oral glucose tolerance test values of:  >180 mg/dL at one hour, >155 mg/dL at two hours or >140 mg/dL at 3 hours).[15]

Why is it important for gestational diabetes to be controlled?

For women who have gestational diabetes mellitus, it is important that the glucose is kept in the normal range as much as possible since gestational diabetes mellitus is associated with an increased risk of complications for the baby and the mother.

It is important to work closely with the healthcare provider to ensure the glucose levels don’t go too low (hypoglycemia) as that can also cause problems.

Are pregnant women who snore more likely to have depression than those who don’t snore?

A study comparing pregnant women with habitual snoring to pregnant women who did not have habitual snoring found that pregnant women with habitual snoring had about twice as likely to score high on the depression questionnaire(Edinburgh Postnatal Depression Scale which is a 10 item depressive symptom screening questionnaire for pregnant and post-partum women).[16]

In the study, 43% of women with snoring scored high when compared to 23% of non-snoring women who scored high on the questionnaire.[16]

What are the surgical treatment options for snoring during pregnancy?

Medical management should be exhausted prior to considering any surgery.

It must be remembered that the snoring should get better after the delivery of the baby and that the snoring will likely improve and could go back to the pre-pregnancy frequency and loudness once the woman is back to the pre-pregnancy weight.

But are there barriers to weight loss during pregnancy?

There are barriers to weight loss after the delivery, for example: given the frequent awakenings that newborn babies experience, and the fact that the baby’s mother will likely be feeding the baby every few hours, these make it difficult to diet and exercise.

Despite the challenges that women face with snoring after delivering their baby, it is possible that the snoring will stop once effective treatment is started.

Will snoring while pregnant go away during the pregnancy?

It is difficult to predict if the snoring will go away. If the woman is gaining a significant amount of weight and she is entering the second or third trimester, then the snoring may actually get worse with time.

If there are other causes for the snoring, then they should be explored. A sleep study will help determine the need for treatment.

What are the medical treatment options for snoring during pregnancy?

Medical treatment options for snoring during pregnancy:

General recommendations that can help reduce snoring during pregnancy include:

  • Avoiding sedating medications before sleep,
  • Avoiding alcohol (which should be done regardless during pregnancy),
  • Maintain a healthy weight,
  • Treat nasal blockage,
  • Try to stay off of your back during sleep, and
  • Try to reduce eating foods within 3 hours of going to bed.

How is nasal obstruction treated in pregnancy?

Nasal sinus rinses (lavages) with over the counter and prescribed lavages can be performed.

Two concerns with nasal lavages would be:

  • The buildup of organisms in the bottle and bottle cap used to rinse, and
  • The source(s) of the water.

Cleaning of the bottle and the bottle cap should be performed as directed on the manufacturer’s instructions.

Water placed into the lavage bottle should be distilled as to avoid organisms from the water, especially if the tap water is not filtered.

Can nasal steroids be used during pregnancy?

Nasal medications have been shown to help improve nasal breathing, as with any medication during pregnancy, there are not many studies evaluating the effect of medications in humans.

The United States’ Federal Drug Administration (US FDA) used to have a Pregnancy Risk Category (A, B, C, D or X).

Hasn’t the US FDA removed the Pregnancy Risk Categories?

Yes. The US FDA removed the categories because millions of women take multiple medications and therefore, they switched to Pregnancy and Lactation Labeling Rule

Using the previous US FDA Pregnancy Categories, most intranasal corticosteroids were listed as Category C (animal reproductive studies have shown adverse effects, but there are no adequate or well-controlled studies in humans, and if the benefits from the use of the drug in pregnant women may be acceptable despite its potential risks).[17]

An exception to the FDA Pregnancy Risk Category C is budesonide, which was upgraded from Category C to a Category B (animal reproduction studies have failed to demonstrate a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women) after a Swedish birth registry was studied extensively.[17, 18]

We cannot emphasize this enough:  It is important to discuss the risks, benefits, and alternatives to using nasal medications and any medications with a healthcare professional before starting any medications.

Are there other reasons pregnant women should stay off their backs during pregnancy?

Additionally, because the inferior vena cava is located inside the abdomen and a fetus can compress it when a pregnant woman lies on her back.

Thus, by lying on her back there is the possibility of reduced blood flow; therefore, lying with the left side down can help to increase blood flow and nutrients to the placenta and the fetus.

How can positive airway pressure therapy help a snoring woman?

Snoring with obstructive sleep apnea is commonly treated with positive airway pressure therapy.

If you had a sleep study and were found to have obstructive sleep apnea, then positive airway pressure therapy (PAP) is a good treatment option.

The devices are commonly referred to as CPAP (continuous positive airway pressure) or APAP (auto-titrating positive airway pressure) devices.  PAP treatment needs to be monitored and PAP pressures need to be adjusted appropriately by an experienced healthcare provider.

The sleep healthcare provider will prescribe the PAP treatment according to multiple factors, such as whether there was a titration portion to the sleep study (where the PAP therapy was started at night during the sleep study).

Sometimes the sleep healthcare provider may base your prescription using variables such as your age and size.

Pregnant woman using a CPAP machine. The CPAP machine helps to reduce the obstructions and should eliminate the snoring. BladeMD.com
Pregnant woman using a CPAP machine. The CPAP machine helps to reduce the obstructions and should eliminate the snoring.

Is close follow-up necessary after starting positive airway pressure therapy?

Yes, it is important to follow-up closely after starting PAP therapy in order to ensure it is working well and so that adjustments to the pressures, humidification, mask, etc. can be made in order to improve the overall use and effectiveness of the PAP treatment.

By design, PAP treatment should eliminate snoring, in fact, if it does not eliminate the snoring, then likely the pressure on the device is set to low. This makes sense because if the pressure is too low, then the airway can still obstruct at night and this can allow the snoring to persist.

What if the woman has snoring alone? Can she use PAP therapy?

Generally speaking, insurance doesn’t cover the cost of PAP therapy if the snorer does not have obstructive sleep apnea.

If she wants to try PAP therapy anyway, then she should discuss this with her sleep physician or healthcare provider.

Can a pregnant woman have surgery for snoring?

Surgery during pregnancy is generally avoided because of the potential effects of the medications on the fetus.

Snoring surgery in the operating room:

It is unlikelythat elective surgery for snoring during pregnancy would go to the operating room as this would expose both the mother and the unborn child to general anesthesia.

Snoring surgery in the clinic under local anesthetic:

Snoring surgery in a pregnant woman would more likely take place in a clinic and with the use of local anesthetic.

Considerations regarding the local anesthetic include that the unborn child’s organs are actively being formed in the first trimester and teratogenic effects are a concern.

But if a pregnant woman has local anesthetic, won’t the medication go to the baby too?

Yes. Medications that are in the mother travel through the bloodstream into the placenta and then into the fetus. Therefore, significant caution needs to be exercised; or just wait until after the delivery of the baby.

During the second and third trimesters, the fetus could still have reactions to the local anesthetic, even at low doses.

Additional risks of snoring surgery include the risk of bleeding and infection.

Healing from snoring surgeries can take weeks, and the scar tissue formed after healing can take about 3 months to stiffen, therefore, the beneficial effects of any surgery may not be seen until after the delivery.

So what are the options for surgery vs medical management for snoring?

Because of the potential of the local anesthetic to travel to the fetus and the potential for infection, medical management should be the primary treatment for snoring during pregnancy.

**It is key to note that ultimately, any decision for doing any testing or pursuing any treatment is between the snorer and her healthcare provider.

Other questions:

Does snoring go away after pregnancy? When will the snoring stop?

If the woman had no snoring prior to the pregnancy and she returns to her pre-pregnancy weight, then it is possible that the snoring will go away at that point.

Obesity is a risk factor for sleep-disordered breathing prior to pregnancy, and with additional weight gain during pregnancy can make the snoring worse.

Can snoring during pregnancy predict whether the baby is a boy or girl?

The prediction of gender-based on snoring is a myth. There is no scientific evidence in the literature (PubMed/MEDLINE or Google Scholar) that demonstrates an increased incidence of boy or girl deliveries based on whether the mother snored during pregnancy.

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Thank you.

Resources and references for snoring during pregnancy:

Helpful Online Resources:

What are reliable resources for snoring, sleep apnea, insomnia, and other sleep disorders?

For more information on sleep medicine in general, visit the patient information section at The American Academy of Sleep Medicine at the link:

https://aasm.org/about/patient-info/

For sleep education resource from at The American Academy of Sleep Medicine that describes common sleep disorders, support for patients, videos and sleep products go the link below:

http://sleepeducation.org/

What are the reliable resources for diabetes during pregnancy?

The American Diabetes Association:

http://www.diabetes.org/

What is a good resource for pregnancy information?

The American College of Obstetricians and Gynecologists:

https://www.acog.org/

Government Disclaimer: The views expressed in this website are those of the author(s) and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US Government.

References:

1.            Li, L., et al., Association between Sleep-Disordered Breathing during Pregnancy and Maternal and Fetal Outcomes: An Updated Systematic Review and Meta-Analysis. Front Neurol, 2018. 9: p. 91.

2.            Quinn, S.J., N. Daly, and P.D. Ellis, Observation of the mechanism of snoring using sleep nasendoscopy. Clin Otolaryngol Allied Sci, 1995. 20(4): p. 360-4.

3.            Izci-Balserak, B. and G.W. Pien, Sleep-disordered breathing and pregnancy: potential mechanisms and evidence for maternal and fetal morbidity. Curr Opin Pulm Med, 2010. 16(6): p. 574-82.

4.            Frederick, I.O., et al., The prevalence and correlates of habitual snoring during pregnancy. Sleep Breath, 2013. 17(2): p. 541-7.

5.            Loube, D.I., et al., Self-reported snoring in pregnancy. Association with fetal outcome. Chest, 1996. 109(4): p. 885-9.

6.            Louis, J.M., et al., Predictors of sleep-disordered breathing in pregnancy. Am J Obstet Gynecol, 2018. 218(5): p. 521.e1-521.e12.

7.            Maasilta, P., et al., Sleep-related disordered breathing during pregnancy in obese women. Chest, 2001. 120(5): p. 1448-54.

8.            Saha, S., et al., Effects of changing in the neck circumference during sleep on snoring sound characteristics. Conf Proc IEEE Eng Med Biol Soc, 2015. 2015: p. 2235-8.

9.            Dzieciolowska-Baran, E., et al., Rhinitis as a cause of respiratory disorders during pregnancy. Adv Exp Med Biol, 2013. 755: p. 213-20.

10.          Hsia, J.C., M. Camacho, and R. Capasso, Snoring exclusively during nasal breathing: a newly described respiratory pattern during sleep. Sleep Breath, 2014. 18(1): p. 159-64.

11.          Brown, N.T., J.M. Turner, and S. Kumar, The intrapartum and perinatal risks of sleep-disordered breathing in pregnancy: a systematic review and metaanalysis. Am J Obstet Gynecol, 2018. 219(2): p. 147-161.e1.

12.          Dunietz, G.L., et al., Maternal Weight, Snoring and Hypertension; Potential Pathways of Associations. Am J Hypertens, 2018.

13.          Qiu, C., et al., Risk of glucose intolerance and gestational diabetes mellitus in relation to maternal habitual snoring during early pregnancy. PLoS One, 2017. 12(9): p. e0184966.

14.          Carpenter, M.W. and D.R. Coustan, Criteria for screening tests for gestational diabetes. Am J Obstet Gynecol, 1982. 144(7): p. 768-73.

15.          Köşüş, N., et al., Effect of number of abnormal oral glucose tolerance test (OGTT) values on birthweight in women with gestational diabetes. The Indian Journal of Medical Research, 2013. 137(1): p. 95-101.

16.          O’Brien, L.M., J.T. Owusu, and L.M. Swanson, Habitual snoring and depressive symptoms during pregnancy. BMC Pregnancy Childbirth, 2013. 13: p. 113.

17.          Alhussien, A.H., R.A. Alhedaithy, and S.A. Alsaleh, Safety of intranasal corticosteroid sprays during pregnancy: an updated review. Eur Arch Otorhinolaryngol, 2018. 275(2): p. 325-333.

18.          Norjavaara, E. and M.G. de Verdier, Normal pregnancy outcomes in a population-based study including 2,968 pregnant women exposed to budesonide. J Allergy Clin Immunol, 2003. 111(4): p. 736-42.