Sleeping Poorly While Pregnant May Not Be “Normal”Sleeping Poorly While Pregnant May Not Be “Normal”

Trouble sleeping is so ubiquitous in pregnancy that it is easily overlooked as a cause of significant morbidity.

Some sleep disorders often manifest for the first time in pregnancy. Disturbed sleep also may trigger or worsen depression and anxiety, disrupt a woman's relationship with her partner and family, and hamper bonding with her newborn. Its effects may delay a woman's return to work or impede job performance.

Although sleep laboratory studies are the gold standard for research in the field, “it's hard to persuade pregnant subjects to spend several nights in the lab,” concedes sleep researcher Kathryn Lee, RN, PhD.

In the past decade, however, researchers have brought polysomnographic equipment into the home or used wrist-worn activity monitors known as actigraphs, which provide a reliable surrogate measure of sleeping and waking, said Lee, a professor of family health care nursing at the University of California, San Francisco (UCSF), School of Nursing. Using such techniques, she and other researchers have documented changes in sleep before pregnancy, during pregnancy, and after delivery.

In one study, Lee and colleagues used home polysomnography to monitor the sleep of 45 healthy women, aged 25 to 39 years, who were planning to become pregnant within the next year. The researchers assessed sleep in both the follicular phase (days 4 to 10) and the luteal phase (days 16 to 25) of the menstrual cycle.

Thirty-three of the women conceived; they included 16 nulliparas and 17 multiparas whose children slept through the night. Researchers monitored the women's sleep at 11 to 12 weeks, 23 to 24 weeks, and 35 to 36 weeks of gestation. In 29 of those women, they also studied sleep at 3 to 4 weeks and 11 to 12 weeks postpartum.

The women said daytime sleepiness and fatigue were among their earliest symptoms of pregnancy, sometimes preceding morning sickness. Significant changes in sleep showed up as early as weeks 11 to 12 of pregnancy, the researchers found. Women averaged about 7.4 hours' sleep then, about 30 minutes longer than at baseline, but they awakened more often.

As pregnancy progressed, the associated body changes interfered increasingly with the women's sleep. Pressure from the growing uterus on the bladder required them to get up at night to urinate. Fetal movement, breast tenderness, low back pain, and leg cramps made it hard to find a comfortable sleep position. By the third trimester, the women averaged 6.9 hours' sleep, and they lay awake for 11% of their time in bed. By comparison, a healthy young adult typically spends less than 5% of the night awake.

“We tell pregnant women, ‘You need to eat for two and sleep for two’,” Lee said. Daytime naps can help compensate for lost nighttime sleep.

One month after delivery, the women—all nursing—slept only about 6.2 hours on average and spent nearly one fourth of their time in bed awake. By 3 months, they still averaged only about 6.3 hours' sleep. The greater the sleep disturbance, the higher their fatigue (Lee KA et al. Obstet Gynecol. 2000;95:14-18).

In a follow-up study with Lee, Caryl Gay, PhD, also of UCSF, used sleep diaries, questionnaires, and actigraphs to estimate sleep and fatigue in 72 heterosexual couples, all first-time parents, in the last month of pregnancy and first month postpartum.

They found the newborn's arrival cut total sleep time and increased awakenings in both parents, mothers more than fathers. Most mothers were nursing. In this study, 93% of babies slept in their parents' bedroom, and 51% regularly slept in the parents' bed. (See box on parent-infant bed sharing.)

Fathers maintained stable 24-hour sleep patterns, while mothers slept less than fathers at night, but more during the daytime. Throughout the study, fathers—most employed outside the house—slept less over the 24-hour day than mothers did, about 7 hours on average after the newborn's arrival, while the mothers managed about 38 minutes more. Nearly half (49%) of the women worked outside the house in their last month of pregnancy, but only 4% did so one month after delivery. Both parents reported similar levels of postpartum fatigue (Gay CL et al. Biol Res Nurs. 2004;5:311-318).

Most women report mild and short-lived postpartum blues in the first 2 weeks or so after delivery. Those reporting high fatigue on a standard checklist at day 14, however, are more apt to develop symptoms of postpartum depression than those with lower fatigue scores, Elizabeth Corwin, PhD, found in a study of 42 mothers of singletons (Corwin E et al. J Obstet Gynecol Neonatal Nurs. 2005;34:577-586).

The effects of fatigue may be even greater for parents of twins. “Mothers of singletons may be able to nap while the baby naps, but mothers of twins rarely have that opportunity,” observed Elizabeth Damato, PhD, RN, assistant professor of nursing at Case Western Reserve University's School of Nursing, Cleveland, Ohio.

In a pilot study of 10 first-time parents of twins, Damato found both mothers and fathers managed only about 5 to 6 hours of sleep per 24 hours. Both parents reported similar levels of fatigue. She used actigraphy and sleep diaries to monitor the couples for 4-day periods at 2, 12, and 20 weeks after the twins left the hospital. All twins had a gestational age of 33 weeks or greater.

Several of the mothers were recovering from cesarean delivery; some had been on antepartum bed rest to forestall premature delivery. Both situations are common in multiple births, which have become more frequent in recent years with the growing use of fertility medications, Damato noted.

Tired parents spend less time picking up, talking to, and looking at babies, Damato said. In a planned study of sleep and fatigue in 100 mothers and fathers of twins, Damato hopes to develop interventions to promote parent-child interaction.

Restless legs syndrome (RLS) and obstructive sleep apnea (OSA), a sleep-related breathing disorder, often develop for the first time in pregnancy, usually in the last trimester. RLS may cause severe sleep deprivation, while OSA has been associated with an increased risk of preeclampsia and other adverse maternal-fetal outcomes.

RLS, which triggers crawling sensations in the legs that prompt a nearly irresistible urge to walk around, develops in an estimated 1 in 4 pregnant women. In some, it occurs only during pregnancy. It more often persists or reappears later in women with a positive family history of the disorder. RLS affects an estimated 5% to 10% of adults.

RLS usually worsens in the evening or at night, making it hard to fall asleep and stay asleep. People with the disorder commonly report not being able to get more than 5 hours of sleep per night, an average lower than that of people with virtually all other persistent sleep disorders, according to the International Classification of Sleep Disorders Diagnostic & Coding Manual, 2nd edition (Westchester, Ill: American Academy of Sleep Medicine, 2005).

RLS may be associated with a related condition, periodic limb movements during sleep (PLMS), which involves repeated contractions of the anterior tibialis muscle during sleep. This condition may produce more fragmented sleep or daytime sleepiness, but in some cases, it is asymptomatic and does not require treatment.

“RLS clearly is related to iron status,” said Richard Allen, PhD, codirector of the Johns Hopkins Center for RLS. “What matters most is iron status before pregnancy,” he said. “After pregnancy starts, it's hard for a woman to catch up.” All women considering pregnancy should have their serum ferritin and percentage of transferrin saturation checked.

If the ferritin level is less than 50 ng/mL or transferrin is less than 20%, Allen said, oral iron treatment (such as 325 mg of iron sulfate with 200 mg of vitamin C, three times daily on an empty stomach), if tolerated, may be appropriate. The treatment generally can be stopped once ferritin comes close to or exceeds 50 ng/mL. Oral iron treatment requires regular blood tests to avoid iron overload, particularly from previously undetected hemochromatosis, he cautioned. It generally should be stopped, he said, if transferrin saturation exceeds 50%.

Snoring raises a red flag warning for OSA. Fewer than 5% of healthy women report snoring before pregnancy, but about 25% to 30% report it by the end of pregnancy. While snoring is the most common symptom of OSA, it is less specific for OSA than gasping, choking, difficulty breathing, or witnessed pauses in breathing. “Women with such symptoms need further evaluation, which may include polysomnography,” said Grace Pien, MD, assistant professor of medicine at the University of Pennsylvania School of Medicine, in Philadelphia.

Some studies link snoring in pregnancy to increased risks for gestational hypertension, preeclampsia, and the delivery of infants small for their gestational ages.

Pien and colleagues at Penn's Center for Sleep and Respiratory Neurobiology prospectively assessed symptoms of sleep-disordered breathing and daytime sleepiness in 155 pregnant women. Using questionnaires in pregnancy and after delivery, they found that symptoms of sleep-disordered breathing and excessive sleepiness increased significantly from the first trimester to the month of delivery. The magnitude of changes in normal-weight subjects suggested some developed OSA in pregnancy, the researchers concluded (Pien G et al. Sleep. 2005;28:1299-1305).

Pier and colleagues are currently using polysomnography to assess 100 women, ranging from normal-weight to morbidly obese, in their first and third trimesters. One fourth of 71 subjects studied so far have met criteria for mild OSA by the third trimester. The researchers will assess whether OSA increases the risk for adverse maternal-fetal outcomes.

Parent-infant bed sharing, common in many cultures, has increased in the United States and other Western countries in recent years, particularly among breastfeeding mothers. The American Academy of Pediatrics (AAP) recommends that newborns share the parents' bedroom, but not their bed. “Infants may be brought into the bed for nursing or comforting, but should be returned to their own crib or bassinet when the parent is ready to return to sleep,” the AAP advises (SIDS Task Force. Pediatrics. 2005;116:1245-1255).

The recent AAP statement may not be the last word on this topic. The AAP SIDS Task Force members and sleep specialists are scheduled to explore cultural considerations and safe infant sleeping practices at the Pediatric Sleep Medicine annual meeting this month and the Associated Professional Sleep Societies annual meeting in June.