Rock-A-Bye Baby: With Less Sleep, New Moms Age Faster

What do the Exxon-Valdez oil spill and the Chernobyl nuclear accident have in common? Someone fell asleep “behind the wheel.” Lack of sleep has been linked to accidents large and small, from medical errors and industrial accidents to airplane crashes. Each year, up to 100,000 car accidents and 1,550 deaths are caused by exhausted drivers; drowsy driving impairs alertness and reaction time as much as driving while drunk. 

But not only can lack of sleep lead to fatalities, but it can also lead to faster aging, according to new research published in the journal Sleep Health. These findings suggest that insufficient sleep duration during the early postpartum period is linked to accelerated biological aging — the deterioration in the health of our cells, tissues, and organs.

Co-author Christine Dunkel Schetter, a distinguished professor of psychology and psychiatry at UCLA, said the study results “and other findings on maternal postpartum mental health provide impetus for better supporting mothers of young infants so that they can get sufficient sleep — possibly through parental leave so that both parents can bear some of the burden of care, and through programs for families and fathers.” 

How does postpartum sleep loss affect health?

Anyone who has parented infants and young children is familiar with some degree of sleep deprivation. Routine sleep disruptions often result in insufficient sleep for the parents. In the first six months of life, in particular, infant sleep patterns are wrought with nighttime awakenings, primarily due to frequent feedings, a responsibility that often falls on mothers. Thus, for many mothers, postpartum is a time of poor sleep quality and shortened sleep duration.

Although there is evidence that this disjointed and insufficient sleep during postpartum impacts daytime functioning, including increased fatigue, mood disturbances, and sleepiness, the impact of postpartum sleep disruptions on biological processes related to health is less clear. A considerable body of research has demonstrated that inadequate sleep and chronic poor sleep quality increase vulnerability to declining health.

“The early months of postpartum sleep deprivation could have a lasting effect on physical health,” said the study’s first author, Judith Carroll, UCLA’s George F. Solomon Professor of Psychobiology. “We know from a large body of research that sleeping less than seven hours a night is detrimental to health.”

But we know little about the link between sleep and postpartum biological aging. Addressing whether routine sleep insufficiency may be detrimental for health by accelerating biological aging provides novel insight into this normative challenge during early parenthood and evidence for the importance of interventions that might target sleep in this context.

Counting sheep and measuring biological age

In the current paper, researchers from the University of California, Los Angeles tested the premise that short sleep in postpartum would predict older biological age in women one-year post-birth.

To determine biological age, Carroll and colleagues used measurements of epigenetics — changes that affect how your genes work. DNA provides the code for making proteins, which carry out many functions in the cells of our body, and epigenetics focuses on whether regions of this code are “open” or “closed.” Typically, more closed DNA is linked to older biological age.

“You can think of DNA as a grocery store,” Carroll said, “with lots of basic ingredients to build a meal. If there is a spill in one aisle, it may be closed, and you can’t get an item from that aisle, which might prevent you from making a recipe. When access to DNA code is ‘closed,’ then those genes that code for specific proteins cannot be expressed and are therefore turned off.”

Postpartum sleep loss accelerates epigenetic aging

As part of a larger study of pregnancy and postpartum health, 33 mothers provided blood samples for epigenetic aging clock estimates. The current sample of young women studied following birth exhibit a high prevalence of poor sleep quality (64%) and short sleep duration (58%), due mainly to frequent night infant awakenings and feedings.

Carroll and colleagues found that the amount of sleep mothers got six months postpartum could predict their epigenetic age at 12 months. “We found that with every hour of additional sleep, the mother’s biological age was younger,” said Carroll, a member of the Cousins Center for Psychoneuroimmunology at UCLA’s Jane and Terry Semel Institute for Neuroscience and Human Behavior.

These findings suggest that early postpartum sleep loss may be most potent as a contributor to accelerated biological aging. Carroll adds that she, as well as many sleep scientists, considers sleep health to be just as vital to overall health as diet and exercise.

Dunkel Schetter added that while accelerated biological aging linked to sleep loss may increase women’s health risks, it doesn’t automatically cause harm to their bodies. “We don’t want the message to be that mothers are permanently damaged by infant care and loss of sleep,” she emphasized. “We don't know if these effects are long lasting.”

Whether improvements in sleep quality and duration over the postpartum period and beyond might reverse the observed associations with epigenetic aging remains to be tested in a larger cohort with adequate power and additional sampling timeframes. Likewise, whether intervening to extend sleep duration might reverse epigenetic aging has yet to be tested, and future research should consider this important question.

References: 

Carroll JE, Ross KM, Horvath S, et al. Postpartum sleep loss and accelerated epigenetic aging. Sleep Health. 2021;7(3):362-367. doi:10.1016/j.sleh.2021.02.002