This month, our Ask the Experts topic is sleep.Today in the first of a two-part series, Dr. Michele Brown, board certified OB/GYN, discusses the importance of sleep during pregnancy and the issues pregnant women may face when hitting the hay.
“Sleep is the golden chain that ties health and our bodies together.” —Thomas Dekker
Obstetricians are familiar with their pregnant patients complaints of difficulties with sleep. Sleep disturbances occur throughout the night resulting in fatigue during the day. The causes for sleep disturbances are attributable to hormonal, vascular, and physical changes that occur in pregnancy.
Why are sleep disturbances important in pregnancy?
Sleep disturbances are associated with increased morbidity and mortality. Deficient sleep has been associated with decreased learning, motor, and cognitive functioning, poor job performance, poor social relationships, deficits in glucose and fat metabolism and mental health issues. It affects overall quality of life by negatively impacting mood, motivation, and performance. Impaired sleep is also a common element in patients who are depressed and patients who have psychological and behavioral problems.
In pregnancy, there are additional significant impacts on maternal/fetal health such as:
- Prenatal and postpartum depression
- Premature birth rate is two fold greater
- Prolonged labors
- Increased cesarean section rates
- Gestational hypertension
- Intrauterine growth retardation
How prevalent is sleep deprivation in pregnancy and the postpartum period?
The sleep requirement specified by the National Sleep Foundation is quoted as 7 to 8 hours per 24 hour period. We spend one third of our lives sleeping. Women in general, have a higher level of sleep deprivation than men. Women are increasingly found to work outside the home while still maintaining the responsibilities of balancing the household needs and children’s needs. Sleep deprivation occurs in 52% percent of all women. In pregnancy, sleep deprivation is even more frequent, with approximately 75% of women experiencing problems with sleep. Difficulties start in the first trimester and tend to worsen as the pregnancy progresses.
What type of sleep problems occur in pregnancy and postpartum?
EEG sleep tracings in pregnant women have shown profound sleep changes with decreasing sleep duration and reductions in deep and REM sleep. Sleep disturbances worsen with each trimester. Pregnant women have frequent nocturnal awakenings. Postpartum, the need for frequent infant care also disrupts the normal sleep pattern. This often results in frequent daytime napping which disrupts the circadian cycle causing an altered sleep-wake cycle. This normalizes several weeks after delivery.
First trimester—There is an increased requirement for sleep with sleep durations increased by about .7 hours with increased daytime sleepiness. At 11 to 12 weeks, there was an average increase of approximately 30 minutes of nocturnal sleep. However, sleep efficiency and the amount of slow-wave sleep decreased significantly compared to the non-pregnant state.
Second trimester—Total nocturnal sleep time decreases further, however, there is a greater amount of slow wave sleep compared to first trimester.
Third trimester—98 percent of women experience nocturnal awakenings and there is a decrease in the amount of slow-wave sleep (stage 4 sleep) and REM sleep. Most women take daytime naps.
Postpartum—the greatest amount of sleep disturbance occurs in the first month after delivery with an average sleep time of less than 6 hours. Sleep time and efficiency will gradually increase as the baby sleeps more with resumption of uninterrupted sleep occurring at about the 12th week.
Breastfeeding women tend to have greater deep sleep time compared to bottle feeding women, due to the higher circulating levels of prolactin.
What are some of the causes of sleep deprivation in pregnancy?
Physical discomfort from the rapidly expanding gravid abdomen, back pain, nocturia (frequent urination at night), hormonal fluctuations, heartburn, restless legs, leg cramps, stress and anxiety relating to childbirth, pregnancy employment issues and chronic fatigue all contribute to compromised sleep.
What are some of the mechanisms causing adverse pregnancy outcomes due to sleep deprivation?
Pregnancy is marked by elevated estrogen and progesterone levels, which generate sedation and a decrease in rapid eye movement sleep. Hormonal metabolites act by binding on the GABA receptors in the brain causing this effect.
Sleep deprivation has been known to alter immune response. In particular, higher circulating levels of inflammatory markers such as interleukin-1, 2, and 6, tumor necrosis factor, serum cytokine, and C-reactive protein. It is postulated that elevated serum cytokines cause an elevation of prostaglandins which are associated with initiating contractions and causing preterm labor.
Increased inflammation also prevents normal trophoblast invasion which prevents placental perfusion by the spiral arteries. This is commonly found in pregnancies complicated by preeclampsia, and intrauterine growth retardation. In addition, increases in cytokines may result in disturbances in neurochemical transmissions which modulate the hypothalamic-pituitary-adrenal axis. This, in turn, may increase levels of serotonin and catecholamines (norepinepherine, epinephrine, dopamine, and cortisol). Higher levels of these same inflammatory chemicals have been found in patients who have depression. Higher levels of these hormones, caused by the inflammatory response, may also cause decreased glucocorticoid sensitivity resulting in increased obesity and diabetes.
In summary, women need to be informed about the detrimental effects of sleep deprivation on pregnancy. Obstetricians should ask questions pertaining to the quantity and patterns of sleep their patients are experiencing. The majority of women do not proactively report their complaints of sleep deprivation to their physicians. Sleep disturbances could be a prognostic indicator for patients who will be at greater risk of developing emotional disturbances and depression and who should be observed more carefully postpartum. Focusing on remedies for severe sleep deprivation promotes the health and well being of both infant and mother which can improve along with mood and likewise improve performance of the mom-to-be at home and in the workplace.
Stay tuned for next week’s follow up, where Dr. Brown will discuss solutions to your prenatal sleep problems.