Poor Sleep in Pregnancy Can Disrupt the Immune System and Cause Birth-Related Complications, Pitt Study Finds
PITTSBURGH, July 17, 2013 – Poor sleep quality and quantity during pregnancy can disrupt normal immune processes and lead to lower birth weights and other complications, finds a University of Pittsburgh School of Medicine study published today in the journal Psychosomatic Medicine.
Women with depression also are more likely than non-depressed women to suffer from disturbed sleep and to experience immune system disruption and adverse pregnancy outcomes.
“Our results highlight the importance of identifying sleep problems in early pregnancy, especially in women experiencing depression, since sleep is a modifiable behavior,” said Michele Okun, Ph.D., assistant professor of psychiatry at Pitt’s School of Medicine and lead author of the report. “The earlier that sleep problems are identified, the sooner physicians can work with pregnant women to implement solutions.”
Adequate and high-quality sleep, both in pregnant and non-pregnant women as well as men, is essential for a healthy immune system. Pregnancy often is associated with changes in sleep patterns, including shortened sleep, insomnia symptoms and poor sleep quality. These disturbances can exacerbate the body’s inflammatory responses and cause an overproduction of cytokines, which act as signal molecules that communicate among immune cells.
“There is a dynamic relationship between sleep and immunity, and this study is the first to examine this relationship during pregnancy as opposed to postpartum,” added Dr. Okun.
While cytokines are important for numerous pregnancy-related processes, excess cytokines can attack and destroy healthy cells and cause destruction of tissue in pregnant women, thereby inhibiting the ability to ward off disease. For expectant mothers, excess cytokines also can disrupt spinal arteries leading to the placenta, cause vascular disease, lead to depression and cause pre-term birth.
Previous studies conducted postpartum have shown higher inflammatory cytokine concentrations among women who experienced adverse pregnancy outcomes such as preeclampsia and pre-term birth. While infection accounts for half of these adverse outcomes, researchers discovered that behavioral processes such as disturbed sleep also may play a role, given the relationship between sleep disturbance and immune function.
Furthermore, higher concentrations of inflammatory cytokines also are found in depressed individuals.
The study is the first to evaluate all factors — inflammatory cytokines, depression and insomnia — and their possible combined effect on pregnant women. The study examined nearly 170 women, both depressed and not depressed, at 20 weeks of pregnancy and analyzed their sleep patterns and cytokine production levels over the course of 10 weeks (pregnancy-related physiological adaptations are in flux prior to 20 weeks).
The findings reveal:
- Women with depression and poor sleep are at greatest risk for adverse birth-related outcomes. Cytokine levels may be one biological pathway through which this is accomplished, particularly with regard to preterm birth.
- Any shift in immunity, such as poor sleep and/or depression, could set the stage for increased risk for adverse outcomes.
- At 20 weeks, depressed pregnant women have higher levels of inflammatory cytokines compared to non-depressed women.
- At 30 weeks of pregnancy, differences in cytokines among depressed and non-depressed women were negligible, likely because as pregnancy progresses, levels of cytokines normally increase
Disturbed Sleep and Inflammatory Cytokines in Depressed and Nondepressed Pregnant Women: An Exploratory Analysis of Pregnancy Outcomes
Objective Disturbed sleep and depression are potential risk factors for pregnancy complications. Both conditions are known to dysregulate biological pathways responsible for maintaining homeostatic balance and pregnancy health. Depression during pregnancy is associated with poor sleep. Thus, we explored whether disturbed sleep was associated with inflammatory cytokines and risk for adverse pregnancy outcomes, as well as whether depression augmented the sleep-cytokine relationship, thereby additively contributing to risk for adverse outcomes.
Methods Interview-assessed sleep and plasma cytokine concentrations were evaluated in a cohort of depressed and nondepressed pregnant women (n = 168) at 20 and 30 weeks’ gestation. Outcomes evaluated included preterm birth, birth weight, and peripartum events.
Among depressed women, short sleep duration (<7 hours) was associated with higher interleukin (IL)-8 across time (β = 0.506, p = .001),
poor sleep efficiency (<85%) was associated with higher IL-6 (β = 0.205, p = .006),
and daytime naps were associated with higher tumor necrosis factor α (β = 0.105, p = .024).
Aspects of poor sleep were associated with having a lower weight baby (p values <.053).
Among depressed women, interferon-γ increased risk for preterm birth (odds ratio = 1.175, p = .032).
Trends for IL-6 and higher birth weight (β = 105.2, p = .085), interferon-γ and lower birth weight (β = −19.92, p < .069), and increased IL-8 and babies weighing less than 4000 grams (odds ratio = 0.72, p < .083) were observed.
Conclusions Although speculative, disturbed sleep may disrupt normal immune processes and contribute to adverse pregnancy outcomes. Exploratory analyses indicate that depression modifies these relationships.