Sleep During Pregnancy
How Pregnancy Affects Sleep
Sleep disturbance is a common complaint of pregnancy. Beginning almost immediately upon conception, pregnant women complain of disrupted nocturnal sleep and daytime fatigue. Data indicate that up to 75% of pregnant women experience some form of sleep disruption during pregnancy, with about 25% reporting significant sleep complaints in the first trimester. Sparse data are available that indicate what to expect regarding the timing, degree, frequency, and/or severity of a specific pregnancy-related sleep disturbance.
Sleep by trimester
Sleep disturbances occurring during normal pregnancy are typically described separately for each of the three trimesters, often for the sake of simplicity. Initially in the first trimester women complain of increased fatigue and report taking more naps; however, it does not appear that women sleep fewer total hours, take longer to fall asleep once they turn off the lights or have poorer sleep efficiency (defined as the total amount of time a person slept divided by the total amount of time spent in bed) during the nocturnal sleep period.
During the second trimester, sleep patterns improve slightly compared to those from the first trimester. Women report an improvement in energy and less fatigue. Sleep quality remains disturbed due to continued changes in the body as the baby grows.
It is during the third trimester that the majority of sleep disturbances occur. Again, physical size and increases in steroid hormones are the primary contributors. Progesterone increases your respiratory rate, which, in addition to increased blood volume and a restricted diaphragm, is responsible for increased heart rate and complaints of shortness of breath. Meanwhile, low estrogen can increase your fatigue and daytime sleepiness. Women complain of esophageal reflux and heartburn, especially during sleep. Lastly, the risk of restless legs syndrome is particularly increased during this period. The prevalence in the first trimester is about 12% increasing to approximately 25% in the third trimester.
Common Pregnancy-Related Sleep Disturbances
There are various methods to classify and measure sleep disturbances. Sleep disturbances relevant to pregnancy are typically classified as: disturbed sleep quality, poor sleep continuity, short/long sleep duration, restless legs syndrome, and sleep disordered breathing. The subjective perception of poor sleep is the most commonly assessed sleep disturbance during pregnancy, with sleep quality typically declining as pregnancy progresses. Sleep continuity, another measure of sleep, is the degree of interruption in a sleep period. Several measures describe how continuous sleep is, including how long it takes you to fall asleep, the number of awakenings and total minutes spent awake each night. Women often complain that sleep is interrupted and fragmented during pregnancy. A frequent need to urinate, physical discomfort, leg and back pain, and heartburn are cited as reasons for poor sleep quality and poor continuity.
Determining the length of the sleep period is also a common measure. Sleep duration varies throughout pregnancy, decreasing slightly by term. Women often increase time spent in bed to try to preserve sleep duration across pregnancy. Restless leg syndrome is a sleep disorder that typically begins in the evening and often prevents a person from falling asleep. It is characterized by an irresistible desire to move the legs that is accompanied by an uncomfortable or “creepy-crawly” sensation in the legs. It can contribute to poor sleep continuity and quality. It is common during pregnancy with rates reaching 27% by the third trimester. Finally, snoring and sleep disordered breathing increase, particularly during the third trimester with a return to normal rates after delivery. Snoring occurs in up to 40% of pregnant women and is a risk factor for sleep apnea. Sleep disordered breathing includes pauses in breathing or the amount of air breathed in during sleep. It can greatly disturb sleep quality, continuity and duration. Sleep disordered breathing occurs in about 14% of pregnant women compared to 4% in non-pregnant women.
Sleep and Adverse Outcomes
Sleep disturbances among women who are not pregnant are associated with increased risk for disease. Poor sleep quality is associated with increased risk for depression and insulin resistance and Type 2 diabetes, while short sleep duration is associated with increased incidence of cardiovascular disease, diabetes, obesity, as well as increased all-cause mortality.
We have limited data linking sleep disturbances and adverse pregnancy outcomes. Shorter sleep duration in late pregnancy is associated with longer labor times and increased cesarean section rates. Women with preeclampsia (in which a woman has very high blood pressure and protein in her urine) have poorer sleep quality and continuity than women without preeclampsia. Sleep disordered breathing and snoring are linked with increased risk for preeclampsia, gestational hypertension, and small-for-gestational-age infants.
Conclusions
Pregnancy is a period during which you may experience sleep disturbance and daytime fatigue. Decrements in sleep quality, continuity and duration, as well as increased prevalence of certain sleep disorders, may have consequences for pregnancy outcomes. In spite of the high rates of sleep disturbance, little is known about the possible adverse effects of sleep disturbance on maternal-fetal health. The emerging evidence suggests that significant sleep disturbance may elevate risk of pregnancy complications. Early identification of problematic sleep disturbance during pregnancy may assist in preventing adverse outcomes.
We suggest speaking to your physician if you are experiencing any of the mentioned problems.
Reference List
Brunner,D.P., Munch,M., Biedermann,K., Huch,R., Huch,A., Borbély,A.A., 1994. Changes in sleep and sleep electroencephalogram during pregnancy. Sleep 17, 576-582.
Lee,K.A., 2006. Sleep during pregnancy and postpartum. Lee-Chiong,T. (Ed.) Encyclopedia of Sleep Medicine. John Wiley & Sons, Inc, pp. 629-635.
Mackenzie,R., Walker,M., Armson,A., Hannah,M.E., 2006. Progesterone for the prevention of preterm birth among women at increased risk: a systematic review and meta-analysis of randomized controlled trials. Am J Obstet Gynecol 194, 1234-1242.
Okun,M.L., Coussons-Read,M.E., 2007. Sleep disruption during pregnancy: how does it influence serum cytokines? J Reprod Immunol 73, 158-165.
Pien,G.W., Schwab,R.J., 2004. Sleep disorders during pregnancy. Sleep 27, 1405-1417.
