Jan. 4, 2000 (New York) -- Women who begin to snore habitually during pregnancy may be at an increased risk for high blood pressure and of delivering smaller babies, according to Swedish researchers. In a study appearing in the January issue of Chest, habitual snorers had a higher incidence of high blood pressure, preeclampsia, abnormal accumulation of fluid in the tissues, and weight gain. The women's infants were smaller and had lower scores of physical condition than did the infants of mothers who snored infrequently during pregnancy. High blood pressure and preeclampsia, a condition associated with pregnancy that involves high blood pressure, protein in the urine and fluid retention, developed in more than twice as many snorers as nonsnorers, report Karl A. Franklin, MD, PhD, and colleagues from Umea University Hospital. The authors say that previous studies have shown an association between pregnancy and increased snoring frequency, but that their study is one of the first to suggest a connection to high blood pressure as well an adverse effect of the mother's snoring on the infant. The study included 502 women and their partners who were questioned on the day they gave birth about incidence of snoring, witnessed sleep apnea (stopping of breathing for short periods during sleep) or disruption in breathing during sleep, and daytime fatigue as well as smoking habits, medication use, and whether they had any medical problems or diseases. Overall, 24% of women reported that they had begun snoring or increased their snoring by the third trimester, and 23% said their snoring was habitual in the week before delivery. Of these women, 10% met the definition of preeclampsia with high blood pressure and protein in the urine compared with 4% of infrequent snorers. Fourteen percent of snorers met the definition for pregnancy-induced high blood pressure compared with 6% of infrequent snorers. Women who reported habitual snoring weighed more prior to pregnancy and gained more weight during pregnancy than infrequent snorers. They also experienced more fluid retention. Among the infants, 7% of those whose mothers were habitual snorers were considered small for gestational age at birth compared with 2.6% of those whose mothers did not snore habitually. Apgar scores, which are a measure of an infant's physical health immediately after birth, were lower than average in 12.4% of infants of snoring mothers compared with 3.6% of infrequent snoring mothers. Witnessed sleep apnea, though higher in snorers than infrequent snorers (11% vs. 2%), was not associated with adverse outcomes in the infant.
According to Franklin and colleagues, the findings indicate "that the consequences of increased upper airway resistance during sleep may affect the fetus and supports the previously suggested relationship between sleep apnea and intrauterine growth retardation." Babies with intrauterine growth retardation have delayed development and are smaller than average. The authors say that all the women in their study who were habitual snorers reported that snoring started prior to any sign of high blood pressure or protein in the urine. The researchers conclude that obstruction of the airways during the night is a likely contributor to the development of high blood pressure and preeclampsia in pregnancy, although the exact mechanisms by which snoring could contribute to high blood pressure are unknown. But a sleep expert who has conducted similar research tells WebMD that while the findings are intriguing, there is little evidence in the general population that snoring alone is associated with any health risks. "Snoring as an indicator of sleep-disordered breathing ... is a different story. That has been noted to be associated in a number of studies with [high blood pressure]," says Daniel Loube, MD. "The frequency of sleep-disordered breathing in a population of pregnant women is going to be relatively low, and to say that snoring by itself is a cause of intrauterine growth retardation is a very long reach."
Loube, who is the director of the Sleep Disorders Center at the Virginia Mason Medical Center in Seattle, says that the use of questionnaires rather than clinical sleep studies that could differentiate snoring from sleep-disordered breathing makes it difficult to put much weight into a connection between snoring in the mother and growth retardation in the fetus.
Loube says about one-third to one-half of pregnant women snore, largely as a result of increasing fluid retention in the nasal passages as pregnancy progresses.
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During your pregnancy, you may find yourself snoring for the first time (Balserak 2015, Facco et al 2010, Sarberg et al 2014). About one in 10 mums-to-be snore regularly in their first trimester, rising to almost half of all pregnant women in the third trimester (Balserak 2015).Unfortunately, snoring and congestion tend to get worse as pregnancy progresses. The good news is that, if you started snoring for the first time in pregnancy, you'll probably stop again after your baby's born (Balserak 2015).
During pregnancy, high levels of the hormones oestrogen and progesterone cause the blood vessels in your nose to open wider, causing congestion (Murray and Hassall 2014). Hormones also cause your nasal tissues to swell, adding to the problem (Bourjeily 2014).There's a link between being pre-pregnancy weight and snoring: the higher your BMI was before you conceived, the more likely you are to snore (Balserak 2015, Sarberg et al 2014). This may be due to extra weight around the soft tissue of your neck. This narrows your airways, affecting how well you breathe during sleep, which may result in snoring (Bourjeily 2014).
Lying on your back can make snoring worse (Harding 2014, NHS 2014). Try sleeping on your side instead, and raising your head slightly with a pillow. Getting into the habit of sleeping on your side is better for your baby too as it reduces the risk of stillbirth (Gordon et al 2015, Heazell et al 2017, McGowan et al 2017, Stacey et al 2011). The following tips may also help to reduce your snoring:- Take regular exercise (Harding 2014, NHS 2014).
- Raise the head end of your mattress (this can also help with heartburn) (Harding 2014, NHS 2015).
- Wear a nasal strip or nasal dilator to keep your nostrils wide open (Harding 2014, NHS 2014). You can buy these at pharmacies.
- If you haven't already, cut out alcohol and tobacco. These are triggers for snoring (NHS 2016a), and both are dangerous for your developing baby. The Department of Health advises against drinking any alcohol during pregnancy (DH 2016), and smoking can cause many health problems for your baby (NHS 2016b).
There isn't much evidence that essential oils can help, but some women swear by them. In particular, eucalyptus oil and menthol are traditionally used to help with congestion, though you should check with your pharmacist before using them while you're pregnant (UKTIS 2014). Learn more about using essential oils in pregnancy. If none of this helps, and your snoring is keeping your partner awake, investing in some earplugs may make sharing a bed easier (Harding 2014, NHS 2014).If you're snoring often and loudly, you may have a condition called obstructive sleep apnoea (OSA) (CKS 2015). OSA happens when your airways become narrower, briefly stopping your breathing in your sleep (CKS 2015). This can happen repeatedly during the night.
Your partner is more likely than you to notice many of the symptoms of OSA (NHS 2016a), which are:
- loud snoring
- noisy and laboured breathing
- repeated gasping or snorting sounds when your breathing is interrupted for short periods
- not feeling refreshed after sleep and being tired during the day (CKS 2015)
When you stop breathing for short spells, the amount of oxygen in your blood falls. Your heart has to work harder than usual just to help you and your baby function normally. So, if you don't get help for sleep apnoea, in time it can take a toll on your health (Carnelio et al 2017, NHS 2016b). Sleep apnoea is linked with the following conditions, though it's not clear if OSA causes them, or if they just tend to happen at the same time:
Sleep apnoea also leaves you feeling worn out. This increases your chances of falling asleep at work, while you're driving, or while you're caring for your other children (CKS 2015). And if you're very tired in the last few weeks of your pregnancy, you may have a longer labour and a higher risk of needing a c-section (Murray and Hassall 2014, NSF nd).
If you think you may have sleep apnoea, see your GP (CKS 2015, NHS 2016b). She may give you a mouth guard to keep your airway open, or a mask to give you a steady flow of air while you sleep (NHS 2016a)
More pregnancy sleep tips
Balserak BI. 2015. Sleep disordered breathing in pregnancy. Breathe (Sheff) 11(4): 268–77. www.ncbi.nlm.nih.gov [Accessed August 2017]
Bourjeily G, Fung JY, Sharkey KM et al. 2014. Airflow limitations in pregnant women suspected of sleep-disordered breathing. Sleep Med 15(5): 550-5. www.ncbi.nlm.nih.gov [Accessed August 2017]
Carnelio S, Morton A, McIntyre HD. 2017. Sleep disordered breathing in pregnancy: the maternal and fetal implications. J Obstet Gynaecol 37(2): 170-8. www.ncbi.nlm.nih.gov [Accessed August 2017]
CKS. 2015. Obstructive sleep apnoea syndrome. Clinical Knowledge Summaries. cks.nice.org.uk [Accessed August 2017]
DH. 2016. UK Chief Medical Officers' low risk drinking guidelines. Department of Health. www.gov.uk [Accessed August 2017]
Facco FL, Kramer J, Ho KH et al. 2010. Sleep disturbances in pregnancy. Obstet Gynecol 115(1): 77-83.
Facco FL, Ouyang DW, Phyllis C, Zee PC et al. 2014. Implications of sleep disordered breathing in pregnancy. Am J Obstet Gynecol 210(6): 559.
Gordon A, Raynes-Greenow C, Bond D, et al. 2015. Sleep position, fetal growth restriction, and late-pregnancy stillbirth. Obstet Gynecol 125(2):347-55
Harding M. 2014. Snoring. patient.info [Accessed August 2017]
Heazell A, Li M, Budd J et al. 2017. Going-to-sleep supine is a modifiable risk factor for late stillbirth – findings from the Midlands and North of England Stillbirth Case-Control Study. BJOG online first: 20 Nov. onlinelibrary.wiley.com [Accessed December 2017]
McGowan LME, Thompson JMD, Cronin RS, et al. 2017. Going to sleep in the supine position is a modifiable risk factor for late pregnancy stillbirth; Findings from the New Zealand multicentre stillbirth case-control study. PloS ONE 12(6):e0179396. journals.plos.org [Accessed December 2017]
Murray I, Hassall J. 2014. Change and adaptation in pregnancy. In: Marshall J, Raynor M. eds. Myles Textbook for Midwives. 16th ed. Edinburgh: Churchill Livingstone, 143-177
NHS. 2014. Snoring – treatment. NHS Choices. Heath A-Z. www.nhs.uk [Accessed August 2017]
NHS. 2015. Tiredness in pregnancy. NHS Choices. Heath A-Z. www.nhs.uk [Accessed August 2017]
NHS. 2016a. Obstructive sleep apnoea. NHS Choices. Heath A-Z. www.nhs.uk [Accessed June 2017]
NHS. 2016b. Stop smoking in pregnancy. NHS Choices. Heath A-Z. www.nhs.uk [Accessed August 2017]
NSF. nd Pregnancy and sleep. National Sleep Foundation. sleepfoundation.org [Accessed July 2017]
Sarberg M, Svanborg E, Wirehn AB et al. 2014. Snoring during pregnancy and its relation to sleepiness and pregnancy outcome – a prospective study. BMC Pregnancy Childbirth 14: 15. bmcpregnancychildbirth.biomedcentral.com [Accessed August 2017]
Stacey T, Thompson JMD, Mitchell EA, et al. 2011. Association between maternal sleep practices and risk of late stillbirth: a case-control study. BMJ 342:d3403. www.bmj.com [Accessed December 2017]
Tommy’s. 2017. Sleep position in pregnancy Q&A. www.tommys.org [Accessed December 2017]
UKTIS. 2014. Essential oils. BUMPS best use of medicines in pregnancy, UK Teratology Information Service. www.medicinesinpregnancy.org [Accessed August 2017]
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