Controlling for birth weight of the newborn, the researchers found that women who averaged less than six hours of sleep per night had significantly longer labors and were 4.5 times more likely to have cesarean deliveries than women who averaged seven or more hours of sleep. Women who averaged between six and seven hours of sleep per night were 3.7 times more likely to have a cesarean delivery. The study appears in the December issue of the American Journal of Obstetrics and Gynecology.
"It is well known that sleep disturbance and fatigue are associated with adverse physical and psychological outcomes, but this is the first study of its kind to associate sleep disturbance in pregnant women with adverse perinatal outcomes," said lead author Kathryn Lee, RN, PhD, FAAN, professor and the James and Marjorie Livingston Chair in the UCSF School of Nursing.
According to Lee, women often complain to healthcare providers about sleep problems during pregnancy, yet little is known about how sleep affects the lives of childbearing women. It is generally accepted that seven to eight hours of sleep per night is the average needed for healthy adults, while six hours of sleep or less per night is considered severe sleep restriction, she said.
The study assessed sleep of 131 women in their ninth month of pregnancy. Study findings showed that women who slept less than six hours per night had an average labor of 29 hours compared to 17.7 hours for women who received seven or more hours of sleep per night.
"We also learned that women who averaged less than six hours of sleep per night also went to bed later and spent less time in bed, thereby limiting their opportunity for sleep," said Lee. "Women who suffer severe sleep disruption may therefore need to increase the amount of time spent in bed to assure a sufficient amount of sleep."
When examining sleep quality, the researchers found that women who reported having poor sleep three to four days per week about three weeks prior to delivery were 4.2 times more likely to then have a cesarean delivery than women who reported having poor sleep two or fewer days per week. Women who reported having poor sleep five or more days per week were 5.3 times more likely to have a cesarean delivery.
"These findings need to be replicated in other studies, but results suggest clinical assessment of sleep quality and quantity as potential predictors of labor duration and delivery type," said Lee.
During the study, each participant was asked to wear a wrist actigraph for a 48-hour period. The actigraph records motion, or sleep disruption, during the night. While wearing the actigraph, participants also recorded their bed times, wake times, and ratings of sleep quality in sleep logs.
Following delivery, participants provided information about their birth experience, including infant's birth weight, duration of labor, and type of delivery. Labor duration was defined as the time from onset of regular contractions to the time of birth. Delivery type was categorized as spontaneous vaginal, assisted vaginal (the use of forceps or vacuum), or cesarean.
Although working women reported spending less time in bed and feeling more fatigued, work status was not associated with labor duration or delivery type. Maternal age was unrelated to labor and delivery outcomes.
"This serves as an important reminder to healthcare providers to discuss the importance of adequate sleep with expectant mothers," added Lee. "Similar to advice that women should 'eat for two' when pregnant, healthcare providers should consider recommending that women also sleep for two."
Study co-author is Caryl L. Gay, PhD, research associate, family health care nursing, UCSF School of Nursing.
This study is part of a larger randomized clinical trial to test an intervention to improve sleep for new mothers and fathers during the neonatal period. It was supported by a grant from the National Institute of Nursing Research at the National Institutes of Health.
Journal
American Journal of Obstetrics and Gynecology