A Comprehensive Look at Barriers to Sleep in Pregnancy

Getting a good night’s sleep is a constant imperative across all genders, ages, and walks of life. But perhaps it is even more critical for someone “sleeping for two.”¹ The literature supports that, during pregnancy, the need for sleep is increased. Further, a lack of sleep can result in negative pregnancy-related outcomes, like the need for C-Section or prolonged labor.¹

Unfortunately, it is also the case that the greater need for sleep during pregnancy is usually not met with a greater capacity to obtain it. This article will explore some of the many physiologic and psychological obstacles which can result in poor sleep and what can be done to intervene.

Hormonal Drivers of Nocturnal Sleep Fragmentation

While it varies throughout pregnancy, estrogen generally rises during pregnancy.² While not shown in human research, rat studies indicate that estrogen tends to reduce REM sleep.³ The effects of oxytocin have also been attributed to fragmented sleep.¹

One should also be wary of the first trimester – while hypersomnolence is, of course, not a barrier to sleep, it may persist despite additional sleep time. Further, the shortened latency is often attributed to this time period, the progesterone that is likely causing it has been attributed to increasing NREM sleep.⁴

Asthma During Pregnancy

Asthma is famous for its nighttime awakenings, and while pregnancy does not appear to actually cause asthma, it is recognized as the most common chronic illness during the pregnancy period and a time when asthma severity worsens.⁵

The mechanisms for this are poorly understood, and there is some debate on whether it is due to changes in physiology or other factors like non-adherence to asthma medication due to maternal suspicions over harm to the baby.⁵

From a physiologic perspective, oxygen demand increases during pregnancy, the enlarged uterus exerts pressure on the diaphragm, estrogen effects a laryngeal edematous response, and maternal immunity changes in ways that may further predispose to asthma exacerbation.

Increased Incidence of Sleep Disorders

There are a few sleep-specific conditions that pregnant women are often more susceptible to:

1. Obstructive Sleep Apnea (OSA)

Pregnancy sees a lot of women develop sleep apnea. Much of this has been attributed to pregnancy-related weight gain leading to upper airway resistance. Some develop it only during pregnancy, but around 30% of women who become pregnant are already overweight, likely indicating a higher predisposition to OSA. with one study finding that “by the third trimester, 26.7% of women had OSA.”⁶

Another element is educating pregnant women regarding the dangers of untreated sleep apnea during pregnancy, like hypertension, preeclampsia, diabetes, and cardiomyopathy, along with an increase in mortality associated with developing this condition during pregnancy.⁷

Consider a rigorous screening program for pregnant patients, establishing networks with local OB/GYN clinics, and creating additional community outreach programs to increase the awareness of sleep apnea during pregnancy.

2. Insomnia

During pregnancy, insomnia is typically secondary – not only to physiological changes, but also to many of the other conditions currently being discussed, such as OSA, GERD/Nausea, Asthma, Nocturia, Back Pain, etc. One systematic literature review, however, encourages providers to not only treat the primary cause of the insomnia, but also the insomnia itself. This is because insomnia during pregnancy is typically multi-factorial and the likelihood of addressing each etiology entirely is unlikely.⁸

3. Restless Leg Syndrome (RLS)

It’s commonly known in the sleep community that pregnancy tends to cause or exacerbate RLS, particularly in the third trimester – a recent 2023 literature review indicates a pooled prevalence of roughly 13%.⁹ While RLS is still not fully understood, dopaminergic pathways have been identified as contributing to the condition, and, during pregnancy, they may be affected by alterations in iron metabolism.⁸ RLS can contribute to difficulty falling asleep due to the nature of the condition. Assessment of ferritin levels should be performed in symptomatic patients and addressed with iron supplementation if levels are low.⁸ Remember that RLS may not be considered outside of the sleep community, so community networking and relationships with local OB/GYN offices may help to increase awareness and establish referral pathways that support effective screening for a variety of sleep conditions.

GERD and Nausea

Anyone who’s ever met a pregnant person knows of the all-too-familiar nausea and heartburn is very common in pregnancy: it’s been suggested that heartburn affects up to 80% of pregnancies and may be another sequela of hormonal-related changes to progesterone and estrogen.¹⁰ Heartburn itself is often worse at night due to horizontal positioning and is classically associated with frequent awakenings.

Despite nausea and vomiting during pregnancy being so common, mechanisms are still poorly understood, but research hints at the effects of human chorionic gonadotropin (hCG), genetic factors, the influence of thyroid hormone, TNF-alpha, and gastrointestinal motility, among others. In up to 10% of cases, nausea and vomiting progresses in severity to hyperemesis gravidarium, which is associated with poor maternal and fetal outcomes and can influence a great negative effect on sleep.¹¹

Nocturia

Nocturia may affect up to 46-86% of pregnancies, and its origins relate to the increase in plasma and the biomechanical pressure exerted by the growing uterus on the bladder. Several studies indicate it may be the most common urinary complaint faced by pregnant women.¹²

Back Pain

The biomechanics of pregnancy might make it obvious as to why many women develop back pain, but clinicians may not be considering the impact on sleep. In one large cross sectional study, it was found that disturbed sleep and awakenings due to pain was highly associated with back pain.¹³ While many pregnant women may be hesitant to resort to pharmacological intervention, more conservative measures have been recommended as first-line, including massage, training on posture, core stabilization, and TENS unit stimulation for pain relief, potentially in concert with a physical therapist.¹³

Psychogenic Causes of Poor Sleep

Depression and anxiety have often been found alongside poor sleep and insomnia in pregnant women.¹⁴ Despite the availability of antidepressants approved for use during pregnancy, pregnant women may be hesitant regarding pharmacotherapy. Alternatively, consider offering therapy and identify opportunities for lifestyle changes that benefit mental health, like physical activity and maintaining a healthy diet.

The Verdict

When caring for a pregnant patient, do not just assume that sleeplessness is part of the deal. A thorough history will help providers to determine the cause of sleep issues and appropriately screen and guide patients to better nights of rest. Do not just focus on one etiological source for poor sleep but consider them together holistically.

Nathan is a nurse practitioner and freelance writer based in West Palm Beach, Florida. He sees disabled veterans struggling with sleep disturbances in the context of multiple comorbidities. You can find him at clinicious.com or on his LinkedIn profile.

References

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