Researchers watched hours of video of moms as they took care of their babies at bedtime and throughout the night. They found that moms with greater depressive symptoms were more likely to pick up their sleeping babies -- sometimes waking the infant as a result.
These moms were also more likely to respond to all sounds their babies made -- even those like cooing that don't require any action.
The findings appear online in Child Development.
The study included 45 infants aged 1 month to 2 years. Along with the videotaping, researchers gathered information about moms' depressive symptoms and about their feelings about their babies' sleep. The moms also kept sleep diaries.
"It provides insight into how depression affects parenting at night," says study researcher Douglas M. Teti, PhD. He is a professor of human development and psychology at Pennsylvania State University.
Lights, Camera, Action
The cameras started rolling when the parents put their child to bed and continued until the infant woke the following morning. Here's what they recorded:
Moms with greater depression symptoms seemed to be more likely than other moms to seek out babies at night, and wake them up or keep them awake.
"We have no problem with moms wanting to spend time with babies at night. But keeping the child awake is not a good thing," Teti says. "If your baby is sleeping, let your baby sleep."
He suspects that the frequent waking and checking is largely to alleviate a mom's anxieties about her infant's needs and comfort. Mothers who are feeling depressed also may seek out their infants at night for their own emotional comfort.
And the more depressive symptoms the moms reported, the more anxious and worried they appeared to be at night.
When babies don't sleep well at night, it affects how they act in the daytime. Poor sleep also sets the stage for problems in school and behavioral issues.
Teti's advice is to moms struggling with depression is clear: "Address the problem of why she is depressed and seek out some steps and try to deal with it," he says. "Depression is very treatable by talk therapy and/or medication."
Babies whose moms are depressed may be more likely to have sleeping difficulties, but the moms' behaviors were the main driver of infant sleep problems in this study. Now, Teti plans to see if the new findings hold in a group of younger babies and their mothers.
Bedtime Lessons for All Parents
Tiffany Field, PhD, says there are lessons from this study for all parents. She is a research professor of pediatrics at the University of Miami Miller School of Medicine.
The depressed moms in this study were not creating a sleep-friendly environment for their babies. "There was no storytelling and the TV was often blaring," she says.
"You need to let your baby sleep and make the environment conducive to sleep," she says. "Turn the TV off. "