According to many parents who practice “attachment parenting,” moms who share a bed with their kids are more in sync with their child’s needs, more nurturing—more maternal.
But what they really are is more tired. Don’t just take it from me, a mother whose six-year-old still manages to find her way into my bed more often than not. Douglas M. Teti, a developmental psychologist at Penn State who studies the effects of mother-child interactions, has been collecting data on parents’ and young children’s sleep in a longitudinal study called Project SIESTA. He says the data shows that mothers who share a bed or a room with their baby for more than six months after birth are getting a worse night’s sleep than moms who sleep separately from their wee ones, which can have negative effects on other aspects of their lives—including their attachment to their kids.
Teti reels off a laundry list of the downsides of co-sleeping. “Co-sleeping moms are more depressed, more anxious about their babies’ night wakings, more chaotic, report lower levels of co-parenting and are observed as poorer at bedtime interaction,” he says. The nightly bedtime ritual is a key time for parent-infant attachment, and if moms aren’t as responsive to their children’s needs—Teti found that co-sleeping moms expressed more frustration and impatience at bedtime than other moms—that could harm attachment.
“These moms appear to be a stressed bunch,” Teti continued. And high stress is not a recipe for positive attachment.
But wait—isn’t co-sleeping supposed to promote attachment? That’s what attachment parenting advocates will tell you. But that’s not what Teti’s research is telling him.
“This is a controversial topic,” he says. “There are some parents who co-sleep and everything is okay.” For others, though, Teti found that co-sleeping “could be a red flag for family dysfunction.”
Teti appears resigned that he’s about to get hated on by the attachment-parenting camp. “This is not a strong endorsement for [this aspect of] attachment parenting, I hate to say it,” he says. Nonetheless, given that parent-child attachment has been the focus of his research for three decades, he feels it important to let parents know that the practice of co-sleeping may be detrimental to both mother and child. “Poorer sleep can lead to poorer parent-child intereraction,” he says. “Co-sleeping could be a symptom of a larger family problem.”
Unlike most previous studies on the subject, which focus on the quality of baby’s sleep, Project SIESTA also looked at how co-sleeping affects parents, particularly mothers. Teti gathered data from two sources: the mothers’ own reports about how they and their babies fared at night, and movement sensors that both moms and babies wore, called actigraphs. The 167 central Pennsylvania families in Teti’s study fell into one of two groups: those with babies who slept alone earlier than six months of age, and those with babies who slept with one or more parents even after they turned six months old, in some cases all the way up to the child’s first birthday. Teti looked at moms’ reports of their babies’ night wakings for seven consecutive nights at one, three, six, nine and 12 months. He then compared the mothers’ sleep journals with actigraph readings.
Most other studies have relied solely on moms’ recollections, but the additional data provided some surprising revelations.
Co-sleeping moms thought their babies were waking up more frequently than they were in fact, and reported more wakings than moms of babies who slept by themselves. But actigraph results showed the babies were not actually waking up: The co-sleeping moms appeared to be overly sensitive to nighttime movement by their babies, and were reacting to normal arousals or sounds that take place while the babies continued to sleep soundly.
These findings are significant because co-sleeping moms may believe they’re more sensitive to their child’s night wakings, though in reality they’re ignoring their own needs (and not actually helping baby). “It’s the mothers who are suffering,” says Teti. “They are waking up more.”
Could a parenting practice intended to more tightly bind mother to child be backfiring? Sleep-deprived moms are more prone to depression and anxiety. Teti asked mothers in both groups to document symptoms of depression; he found that co-sleeping moms reported more symptoms than other moms. They also fretted more about their babies’ night wakings, worrying that if they didn’t respond immediately, their babies would feel abandoned. And they displayed higher levels of what study observers called “household chaos”—more clutter, disorganization and difficulty keeping appointments. For some mothers, that could contribute further to anxiety, depression and marital troubles.
Avi Sadeh, a child psychologist and director of the sleep laboratory at Tel Aviv University, heard Teti present his research in April at the meeting of the Society for Research in Child Development in Seattle. Sadeh’s own research has confirmed that co-sleeping parents report more night waking than others, even in countries where co-sleeping is the norm, and that if a person is jolted from sleep five times at night for five to 10 minutes at a time, it’s the equivalent of losing up to four hours of sleep.
“A mom can say it’s not a big deal, but it affects their emotional well-being, cognitive ability and tolerance for frustration,” says Sadeh. “As a child psychologist, I prefer having a mom who’s well-rested during the day to one who continually responds during the night.”
Teti also assessed co-parenting practices in the families in his study—the degree to which moms and dads divvied up childcare tasks. He found that co-sleeping families weren’t as skilled at co-parenting, which he speculates could be a function of co-sleeping driving a wedge—literally—between mom and her partner, breeding marital dissatisfaction. “This suggests dads are not necessarily as happy that babies are still in the same room,” says Teti.
And what was the effect of co-sleeping on fathers’ sleep patterns?
“None,” Teti told his audience in Seattle. “It’s embarrassing.”