Pregnancy and Positional Therapy

A significant proportion of non-pregnant people with sleep-disordered breathing (SDB) are classified as position-dependent, which means that they experience most of their breathing abnormalities while lying supine. Positional therapy (PT) is a simple, non-invasive, inexpensive, long-established, safe, and effective intervention for preventing people with positional-dependent SDB from sleeping on their back and thereby prevents exacerbation of their condition, improves it or totally eliminates it [1-6]. PT helps a person avoid an undesired sleeping position through the use of physical barriers (e.g., pillows, wedges) to prevent achieving the position or by use of pressure points (e.g., tennis ball technique) or alarms (e.g., vibration, sound) when in the position in order to precipitate a change to a more desired position.
There are several commercially available PT products for people with positional-dependent SDB. Despite their effectiveness, these devices universally focus on the position of the thorax, neck, and head, which make them of doubtful utility for pregnant women when it is important that the maternal pelvis is not supine. In large studies of positional dependency of SDB in the general population, positional dependency has been shown to be inversely related to BMI [7,8]; therefore, in pregnancy, a state accompanied by rapid weight gain and increased airway edema [9,10], SDB, if present, may be less likely to be dependent on body position. In addition, pregnant women are also significantly different from the general population in various aspects such as anatomy (e.g., gravid uterus, widened subcostal angle, increased thoracic diameter, elevated diaphragm, decreased chest wall compliance), physiology (e.g., increased metabolism, increased oxygen consumption, increased carbon dioxide production) and nocturnal behaviour (e.g., rising up more often during the night to void due to compression of the bladder from the gravid uterus).  An issue particularly specific to pregnancy is that of the impact of the position of the maternal pelvis on maternal, placental, and fetal hemodynamics. No clinically tested PT devices to date, besides the PrenaBelt™, have taken this important factor into account.


Further, vibrational stimuli have been previously demonstrated to have a deleterious effect on sleep quality in individuals without SDB [14,15]. The impact of PT on sleep quality and quantity is of critical importance as poor sleep quality and quantity in pregnancy have been directly linked to adverse outcomes such as postpartum depression [16–18]. Although there are some PT devices that help pregnant women sleep on their side, these devices are characteristically limited in that they inherently ignore the position of the pelvis, are not clinically tested or validated, and/or are prohibitively expensive.

The simplest method of PT is to simply instruct pregnant women to avoid sleeping supine, and anecdotally, when so instructed, most pregnant women respond that they do not sleep supine. However, we have published data indicating that pregnant women do spend a significant proportion of the night sleeping supine [19], they also underestimate this proportion [20], and when asked to maintain a lateral sleeping position, they can do so moderately well but at the cost of reduced sleep quality [21].


[1] M. J. L. Ravesloot, J. P. van Maanen, L. Dun, and N. de Vries, “The undervalued potential of positional therapy in position-dependent snoring and obstructive sleep apnea-a review of the literature,” Sleep Breath., vol. 17, no. 1, pp. 39–49, 2013.

[2] A. Oksenberg and N. Gadoth, “Are we missing a simple treatment for most adult sleep apnea patients? The avoidance of the supine sleep position,” J. Sleep Res., vol. 23, no. 2, pp. 204–210, 2014.

[3] H. Gastaut, C. A. Tassinari, and B. Duron, “Polygraphic study of the episodic diurnal and nocturnal (hypnic and respiratory) manifestations of the Pickwick syndrome,” Brain Res., vol. 1, no. 2, pp. 167–186, 1966.

[4] R. D. Cartwright, “Effect of sleep position on sleep apnea severity,” Sleep, vol. 7, no. 2, pp. 110–114, 1984.

[5] A. Oksenberg, “Positional and non-positional obstructive sleep apnea patients,” Sleep Med., vol. 6, no. 4, pp. 377–378, 2005.

[6] I. G. Robin, “Snoring,” Proc. R. Soc. Med., vol. 41, no. 3, pp. 151–153, 1948.

[7] A. Oksenberg, E. Arons, S. Greenberg-Dotan, K. Nasser, and H. Radwan, “The significance of body posture on breathing abnormalities during sleep: data analysis of 2077 obstructive sleep apnea patients,” Harefuah, vol. 148, no. 5, pp. 304–9, 351, 350, 2009.

[8] M. J. L. Ravesloot, M. H. Frank, J. P. van Maanen, E. A. Verhagen, J. de Lange, and N. de Vries, “Positional OSA part 2: retrospective cohort analysis with a new classification system (APOC),” Sleep Breath., vol. 20, no. 2, pp. 881–888, 2016.

[9] S.-Y. Lee, D.-K. Chien, C.-H. Huang, S.-C. Shih, W.-C. Lee, and W.-H. Chang, “Dyspnea in pregnancy,” Taiwan. J. Obstet. Gynecol., vol. 56, no. 4, pp. 432–436, 2017.

[10] H. Toppozada, L. Michaels, M. Toppozada, I. El-Ghazzawi, M. Talaat, and S. Elwany, “The human respiratory nasal mucosa in pregnancy. An electron microscopic and histochemical study,” J. Laryngol. Otol., vol. 96, no. 7, pp. 613–626, 1982.

[11] M. J. L. Ravesloot, D. White, R. Heinzer, A. Oksenberg, and J.-L. Pépin, “Efficacy of the new generation of devices for positional therapy for patients with positional obstructive sleep apnea: A systematic review of the literature and meta-analysis,” J. Clin. Sleep Med., vol. 13, no. 06, pp. 813–824, 2017.

[12] J. P. van Maanen et al., “The sleep position trainer: a new treatment for positional obstructive sleep apnoea,” Sleep Breath., vol. 17, no. 2, pp. 771–779, 2013.

[13] M. M. Eijsvogel et al., “Sleep position trainer versus tennis ball technique in positional obstructive sleep apnea syndrome,” J. Clin. Sleep Med., vol. 11, no. 2, pp. 139–147, 2015.

[14] P. W. Arnberg, O. Bennerhult, and J. L. Eberhardt, “Sleep disturbances caused by vibrations from heavy road traffic,” J. Acoust. Soc. Am., vol. 88, no. 3, pp. 1486–1493, 1990.

[15] M. G. Smith, I. Croy, M. Ögren, O. Hammar, E. Lindberg, and K. Persson Waye, “Physiological effects of railway vibration and noise on sleep,” J. Acoust. Soc. Am., vol. 141, no. 5, p. 3262, 2017.

[16] L. M. O’Brien, “Sleep disruption and adverse pregnancy outcomes,” BMC Pregnancy Childbirth, vol. 12, no. S1, 2012.

[17] J. J. Chang, G. W. Pien, S. P. Duntley, and G. A. Macones, “Sleep deprivation during pregnancy and maternal and fetal outcomes: is there a relationship?,” Sleep Med. Rev., vol. 14, no. 2, pp. 107–114, 2010.

[18] Y. Yang et al., “Prevalence of poor sleep quality in perinatal and postnatal women: A comprehensive meta-analysis of observational studies,” Front. Psychiatry, vol. 11, p. 161, 2020.

[19] L. M. O’Brien and J. Warland, “Typical sleep positions in pregnant women,” Early Hum. Dev., vol. 90, no. 6, pp. 315–317, 2014.

[20] A. J. Kember et al., “Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial,” BMJ Open, vol. 8, no. 8, p. e020256, 2018.

[21] J. Warland and J. Dorrian, “Accuracy of self-reported sleep position in late pregnancy,” PLoS One, vol. 9, no. 12, p. e115760, 2014.

[22] J. Warland et al., “Modifying maternal sleep position in late pregnancy through positional therapy: A feasibility study,” J. Clin. Sleep Med., vol. 14, no. 8, pp. 1387–1397, 2018.

[23] J. Coleman et al., “The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight,” BMJ Open, vol. 9, no. 4, p. e022981, 2019.

© 2021