Having a baby is the equivalent of deciding that an uninterrupted night’s sleep is overrated. But mothers hoping to get a little more shut-eye by formula-feeding should put that notion to bed. It’s just not true, according to a new study in the December issue of Pediatrics published online Monday.
No matter whether moms breast-fed, formula-fed or did a combination of both, they got the same amount of sleep and considered themselves equally exhausted. Score one for the breast-feeding advocates, who hope this study gives women on the fence another reason to commit to breastfeeding, which conveys well-documented health benefits for baby — and mother. The American Academy of Pediatrics recommends babies be exclusively breast-fed for six months and continue to receive breast milk for at least a year. (More on Time.com: Breast-Feeding: Not Just for Women?)
The research, from West Virginia University (WVU), also turns another new motherhood truism on its head — that annoying and completely unrealistic admonition to “nap when baby naps.” (P.S. It has to do with sleep cycles; keep reading.)
“When a woman has a baby, she is given a whole Welcome to Motherhood basket of advice,” says Hawley Montgomery-Downs, an assistant professor of psychology and coordinator of WVU’s behavioral neuroscience program. “A lot is anecdotal and very little is supported by empirical evidence.”
Most new mothers have likely heard that formula-feeding — and maybe a touch of rice cereal, as my grandma insisted — will help their babies sleep longer. It’s true that formula takes babies longer to digest, while breast milk is processed more fully and quickly because of its composition. But even if bottle-fed babies are sleeping longer, their moms are not, say the researchers. (More on Time.com: Most Babies Sleep through the Night)
Miriam Labbok, director of the Carolina Global Breastfeeding Institute at the University of North Carolina at Chapel Hill calls the results a “helpful finding for the field.”
“The perception is that the breast-feeding mom is up day and night, always breast-feeding,” says Labbok. “But when you’re bottle-feeding, you’re up day and night always bottle-feeding, too.”
That was borne out by the data collected from the new mothers, who were tracked from the beginning of the second week after their baby was born until the end of the twelfth week. The women — divided into groups who breast-fed, formula-fed and alternated back and forth — wore wrist actigraphs, a watch-like device that records movement to determine when sleep occurs. Each morning, they used a PDA to rank their sleep quality from 0 to 100. They also shared how many times they thought they awoke during the night and how long they thought they stayed awake. To top it off, whenever they fed their baby during the day, they would use the PDA to enter how sleepy they felt right then. (More on Time.com: Breastfeeding after Breast Cancer Is Okay)
This wealth of postpartum data yielded a surprising conclusion: there was no difference among the groups.
That, of course, raised other questions. “If it’s true that breast-feeding infants wake up more often but their mothers don’t, there has to be something going on,” says Montgomery-Downs.
Maybe breast-feeding moms wake only to latch their babies on, then return to dreamland. I can certainly vouch for that happening. Or maybe formula-feeding moms catapult themselves into a more alert state as they pad downstairs, flip on the light to prepare a bottle and move around more than a breast-feeding mom. (More on Time.com: Breast-feeding: Does Guilt Play a Role?)
Yet even though these new moms are certifiably wiped out, they’re not sleep-deprived: the 80 mothers surveyed reported getting 7.2 hours of sleep a night.
Yet even if they’re not technically deprived of sleep, they are legitimately being deprived of good sleep. The moms tell of sleeping in bursts, a phenomenon the researchers refer to as “sleep fragmentation.” “This is not a sleep disorder,” says Montgomery-Downs. “This is what new moms do.”
Since sleep fragmentation is the main issue with new moms’ sleep, it makes little sense to nap alongside your baby — unless you know your baby is likely to snooze for at least 90 minutes, which is how long an adult’s sleep cycle lasts. It’s better to just go to bed early and take advantage of the longer chunks of sleep an infant typically experiences at night.
For those breast-feeding moms who crave the occasional night off that formula-feeding provides (since anyone can give a baby a bottle, while only Mom, obviously, can breast-feed), Montgomery-Downs suggests pumping in between sleep cycles, then handing off a bottle of breast milk to dad. (Pumping in the middle of the night when you don’t absolutely have to sounds like a form of maternal waterboarding, but far be it from Healthland to dissuade you.) (More on Time.com: The ‘Mommy Brain’ Is Bigger: How Love Grows a New Mother’s Brain)
Montgomery-Downs called the study’s results “good, objective research” to fend off well-intentioned naysayers such as “practitioners and friends and mothers-in-law who say, ‘We know it’s hard, we know you’re exhausted.’”
“It ought to be reassuring to breast-feeding moms,” she says. “Stopping breastfeeding is not going to be the answer.”
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