Insomnia is a frequent sleep alteration in pregnancy. It may be primary or due to some underlying medical condition, such as anxiety, mood disorders, sleep apnea and restless legs syndrome.
About 80% of pregnant women experience insomnia at some point, and this is worst in the third trimester.
Most researchers think that pregnancy-related insomnia is due to hormonal fluctuations and changes, metabolic alterations, physiological changes, such as frequent bladder filling, and psychological problems. Muscle tone is lower than normal, sleep apnea is more likely, as is snoring because of the high progesterone levels in the body.
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Bladder pressure due to the growing fetus, with nausea and vomiting due to the hCG increases, back pain, fetal movements sometimes interpreted as painful or uncomfortable sensations, the occurrence of leg cramps, and heartburn due to increased gastroesophageal reflux, are all factors that affect sleep in pregnancy especially in the first trimester.
Women who have a tendency to worry or become anxious easily are more prone to insomnia, as are those with increased sensitivity to hormonal changes.
Increased estrogen and progesterone during pregnancy can result in other hormonal fluctuations as well, such as increased free cortisol by competition for the corticosteroid-binding globulin by progesterone. Cortisol is known to increase the state of arousal in some individuals.
Risks of Insomnia in Pregnancy
Pregnancy is a time of anxiety for the expectant mother in many cases, and this may be exacerbated by poor sleep. This causes the quality of life to slip, is a risk factor for mood disorders, and has been found to have a negative impact upon labor duration and mode of delivery.
Insomnia in pregnancy can result in daytime sleepiness, tiredness, mood changes, negative feelings towards the partner, and even towards the baby following birth. The possibility of depression in late pregnancy or postpartum is also more likely in these women.
Difficult Delivery and Low Birth Weight
C-sections were performed 4.5 times more often in women who slept less than 6 hours a night. Babies born to mothers who had less than 8 hours of sleep had low birth weights more often, on average.
These adverse effects are possibly related to an elevated level of pro-inflammatory cytokines, interleukin 6, and C-reactive protein. It has been found that oxytocin levels increase just before labor and this is related to increased insomnia at this time.
Blood Glucose Levels
Blood glucose levels increase by about 4% per hour of lost sleep in pregnancy. Late rises in blood pressure in the third trimester are also noted, as is the risk of gestational diabetes. An increase of one point on the PSQI in early and late pregnancy is associated with a 25% and 18% increase in the risk of preterm birth, respectively.
Sleep disturbances in pregnancy should diagnosed early in order to institute early treatment so as to avoid unnecessary adverse outcomes as the above. Diagnosis is usually based on the clinical history, which means keeping a sleep diary, noting times, such as last meal, bedtime, exercise workout time, times of waking, and nap times if any. The quality of sleep is also noted. The precise nature of the problem, such as difficulty in initiating, or maintaining sleep, or waking too early, should be noted by specific questioning. The environment and emotional makeup of the patient should also be understood.
A reliable sleep questionnaire may be used to document sleep in a comparable and accurate fashion especially in a research setting. One such is the Pittsburgh Sleep Quality Index. Others include the insomnia severity index and the insomnia symptoms questionnaire. Polysomnography is rarely required.
It is necessary to screen such women for anxiety disorders, mood disorders and other sleep disorders. The other disorders include obstructive sleep apnea-hyperpnea, restless legs syndrome (which is in turn linked to labor aberrations, increased sensitivity to labor pain, higher incidence of C-section and preterm labor, and a proinflammatory state if left untreated).
Both non-pharmacologic and pharmacologic measures may be used to help overcome sleep disturbances.
Behavioral therapy is the leading nonpharmacologic modality for insomnia, and includes:
Sleep hygiene: This should be taught to the patient, such as a dark environment, avoiding all triggers for arousal, napping only before noon if required, and exercising at least 4 hours before bedtime, as well as limiting fluids after 5 pm to avoid having to visit the bathroom too often during sleep hours.
Stimulus control is another technique, comprising keeping the bed only for sleep, and in case of insomnia, getting out of bed to do some mild non-arousing activity until one feels sleepy.
Sleep restriction: This refers to charting the actual time spent in sleep and not going to sleep until the hours to projected waking are equal to the actual sleep time. This is thought to help correct circadian cycle shifts and improve sleep efficiency. Once one is actually asleep for 85% or more of the time spent in bed, the bedtime may be shifted back in increments of 15-30 minutes.
Relaxation techniques may help to get one in the right frame of mind, such as progressive muscle relaxation or abdominal breathing, or focusing on relaxing thoughts.
Cognitive therapy: This intervention aims at recognizing catastrophic thinking in relation to insomnia, and encouraging the development of right thoughts about the amount of sleep the patient actually needs, using data gathered through research and the patient’s actual requirement of sleep in the past in order to function properly.
Cognitive behavioral therapy: In the case of insomnia, this includes sleep education, stimulus control, sleep restriction, cognitive therapy, sleep hygiene, and integrating all of these into a functional approach to handling insomnia.
Many physicians are hesitant to prescribe drugs for the management of insomnia in pregnancy, because of various reasons. Restless legs syndrome is one major cause of insomnia and may be treated to some extent by supplementing with vitamins and iron, especially folate-fortified grains. Folate and iron deficiency increases the risk of this condition in pregnancy. Sleep apnea should be treated if present by continuous positive airway pressure (CPAP).
Antihistamines may be the first line, because of their safety in pregnancy. This may be followed by appropriate antidepressant or anxiolytic therapy despite the low risk of teratogenicity, to avoid the greater risk that arises from not treating psychiatric illness in pregnancy. Yet, these should be used only when absolutely required and in the lowest effective doses. Benzodiazepines could cause neonatal hypotonia, sedation, or respiratory problems. However, maternal depression could also cause fetal ill-health.
The use of mood stabilizers is more controversial and must be decided on a case-by-case basis considering the risk of acute mania or depression in pregnancy.