Loved a study published today in Pediatrics. Researchers sought to determine if mothers who breastfed slept less than those who formula fed their babies. I hear lots of talk (at birthday parties to office visits) about how formula or rice cereal creates better infant sleepers. So far, science doesn’t back up these claims. But as every new mom (and dad) knows, sleep is the major commodity during your infant’s first 6-12 months. We really want our babies to sleep through the night. Desperately. Six weeks in, crying is at a peak for infants and mothers are utterly exhausted after a pregnancy, a labor/delivery, and a month or so of very fragmented and dwindling sleep. Not only are we at peace when our babies sleep, we often rest, too. Maternal rest is essential for familial functioning, enjoyment of a baby’s infancy, and simple recovery. Sleep is not just about feeling rested or perceiving that you get more (or less) sleep than the other baby’s mothers on the block. It is about wellness, too. The study asserts that, “a growing body of evidence shows that mothers may not, in fact, do fine with less sleep.” Maternal sleep may affect rates of postpartum depression and an infant’s emotional and cognitive outcome. Getting rest is something we actually CRAVE in the first few months of our baby’s lives. Sleep, at some point, has to be a priority.

Researchers in West Virginia wanted to figure out if mothers of formula fed babies got a better night of sleep compared to those who breast fed or partially breast fed. The motivation behind the study was to dispel any perceived disadvantage of breastfeeding. Before you get up in arms about how bad your night sleep was while breast feeding compared to baby Jane next door who was chugging formula, look at what they did. Sometimes understanding how a study was performed helps you interpret how much weight you put into the results.

Study Design:

  • Two groups of women participated, 80 completed the study in entirety. The first group consisted of first and second/third time moms from 9-16 weeks postpartum. A second group consisted of first time moms from postpartum weeks 2-13.
  • Moms logged their total night time sleep, the number of times they got up to feed their babies, and duration of time they were up each night on a PDA (think old school palm pilot). This is good from a reliability stand point–moms actively filled out information just after their night of sleep so researchers didn’t have to trust memory or recall.
  • Moms wore actigraphs (yup, I had to look this up, too) that monitored their movement. Actigraphs are wrist monitors that help in quantitatively capturing how much sleep moms get by looking at gross body movement.
  • Moms self-scored “sleepiness” using three standardized scales translating daytime functioning. Basically, moms reported their sensations of sleepiness throughout the day.
  • Moms were divided into breast feeding, partial breast feeding, and formula feeding groups to run results.
  • Moms were excluded if they had a history of depression, anxiety disorder, multiples, premature delivery, or had an infant in the NICU.

Drumroll….what the researchers found was that moms didn’t differ (statistically) in the amount of sleep, daytime functioning, or in the sleepiness scales. All moms were getting about the same amount of sleep, feeling the same amount of fatigue, and were awake about the same amount of time at night. The study found no difference in objective sleep (the actigraphs), subjective sleep (moms logging their sleep) or sleepiness between breastfeeding and formula feeding moms. Further, one interesting difference found using actigraph data (objective) was at 10 weeks postpartum, breastfeeding moms has greater sleep efficiency than formula feeders. Huh. I wouldn’t have guessed.

Bottom line:

At least in the first 3 months, switching to formula feedings will not guarantee an improvement in maternal sleep. Some mothers may be led to believe this. Consider talking with your pediatrician if you’re weaning because of sleep deprivation. Particularly if you’re going back to work and worried about the juggle between breastfeeding & work. Of course, there are outliers to this data. Not all women fit into this mold. Further, this data can’t be extrapolated to women who suffer from postpartum depression or anxiety (the study excluded similar moms).

What is your experience? I don’t really remember much this time. I’m not kidding; I can hardly remember those months. With both my boys, I was up multiple times every night in the beginning (of course), and come 6-12 weeks, very bleary-eyed.