October 4, 2010

Pregnancy and the Effects of Sleep

(Ivanhoe Newswire) "“ Getting too little or not enough sleep in early pregnancy is linked to having high blood pressure in the third trimester. It's called preeclampsia, and it can be deadly to the mother and baby. It can keep the baby from getting enough blood and oxygen and can harm the mother's liver, kidney, and brain. This study suggests having proper sleep habits at the beginning of pregnancy helps in keeping blood pressure down and keeping preeclampsia away.
Results show that the mean systolic blood pressure in the third trimester was 114 mm Hg in women with a normal self-reported nightly sleep duration of nine hours in early pregnancy, 118.05 mm Hg in women who reported sleeping six hours or less per night, and 118.90 mm Hg in women with a nightly sleep duration of 10 hours or more in early pregnancy. After adjustments for potential confounders such as age, race and pre-pregnancy body mass index, mean systolic blood pressure was 3.72 mm Hg higher in short sleepers and 4.21 mm Hg higher in long sleepers. Similar results also were found for diastolic blood pressure.

"Both short and long sleep duration in early pregnancy were associated with increased mean third trimester systolic and diastolic blood pressure values," principal investigator and lead author Dr. Michelle A. Williams, professor of epidemiology in the School of Public Health at the University of Washington and co-director of the Center for Perinatal Studies at Swedish Medical Center in Seattle, Wash. Was quoted as saying.

The study also found an association between sleep duration and preeclampsia, a condition that involves pregnancy-induced hypertension along with excess protein in the urine. The risk of developing preeclampsia was almost 10 times higher (adjusted odds ratio = 9.52) in very short sleepers who had a nightly sleep duration of less than five hours during early pregnancy. Overall, about 6.3 percent of participants were diagnosed with either preeclampsia or pregnancy-induced hypertension without proteinuria.

"If our results are confirmed by other studies, the findings may motivate increased efforts aimed at exploring lifestyle approaches, particularly improved sleep habits, to lower preeclampsia risk," said Dr. Williams.

The study evaluated 1,272 healthy, pregnant women who completed a structured interview at 14 weeks gestation. Sleep duration in early pregnancy was evaluated by the question, "Since becoming pregnant, how many hours per night do you sleep?" Only about 20.5 percent of women said they slept 9 hours a night, which was considered the "normal" amount of sleep. About 55.2 percent of women reported sleeping seven to eight hours per night, 13.7 percent slept six hours or less, and about 10.6 percent slept 10 hours or more.

The researchers believe many reasons for high blood pressure being correlated with early pregnancy sleep patterns. Blood pressure drops 10 to 20 percent while sleeping, so short amounts of sleep may raise the average 24 hour blood pressure and heart rate. This could lead to structural changes that affect the blood pressure of the whole cardiovascular system. Sleep restriction also may produce abnormalities in the levels of hormones such as endothelin and vasopressin, which play an important role in the cardiovascular system. The authors suspect that the association between long sleep duration and elevated blood pressures may be related to unmeasured confounders such as, obstructive sleep apnea, depression or insulin resistance.

Dr. Williams tells women who are pregnant or who plan on becoming pregnant to establish a consistent sleep schedule, follow a relaxing bedtime routine, create a comfortable sleep environment, keep T.V. and other distractions out of the bedroom, exercise regularly during the day, eat at least 2-3 hours before bedtime, and avoid caffeine and alcohol before bedtime.

SOURCE: Sleep, published online, October 2010