Mothers and babies who co-sleep or room share get LESS sleep

Exhausted mother and baby on the couch

There’s ongoing controversy in the lactation profession about where infants ought to sleep.

Although considerable data shows that co-sleeping is a major risk factor for sudden infant death, breastfeeding professionals have tried to argue that since co-sleeping purportedly improves breastfeeding rates, and breastfeeding proportedly improves infant health, the benefits of breastfeeding outweigh the risks of co-sleeping. That’s untrue.

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]Breastfeeding, co-sleeping and room sharing lead to poorer quantity and quality of infants’ and mothers’ sleep. [/pullquote]

In an effort to reduce the risk of co-sleeping while maintaining mother-infant proximity, the American Academy of Pediatrics recommends room sharing until age one. There’s very little evidence that room sharing has any benefit, but no matter. It seems to be a good compromise.

What impact does co-sleeping and room sharing have on maternal and infant sleep?

Lactation professionals seem to think that co-sleeping improves the quality and quantity of maternal sleep. Room sharing advocates have not really addressed the issue.

The scientific evidence shows that mothers and babies who co-sleep or room share get LESS sleep and poorer quality (more fragmented) sleep.

For example, Mother-Infant Room-Sharing and Sleep Outcomes in the INSIGHT Study was published in Pediatrics in 2017.

The authors note the importance of sleep to both babies and mothers:

The importance of getting an adequate night’s sleep has been increasingly recognized by professional societies including the American Academy of Pediatrics‍ (AAP) and the American Academy of Sleep Medicine.‍ Inadequate sleep has been associated with poorer cognitive, psychomotor, physical, and socioemotional development, which includes emotion regulation, mood, and behavior in infancy and childhood.‍..[I]nfant sleep has a bidirectional relationship with parent outcomes as demonstrated by associations between infant sleep and parental sleep, maternal sensitivity, relationship quality, parental emotional health, and parenting practices.‍

They note:

The desire to optimize infant sleep duration and consolidation, however, must be balanced with safe infant sleep, a fact reinforced by the 3500 infants who tragically die of sudden infant death syndrome (SIDS) or other sleep-related deaths annually.‍ According to the Eunice Kennedy Shriver National Institute of Child Health and Human Development’s “Safe to Sleep” campaign, most SIDS deaths occur when infants are 1 to 4 months old, 90% occurring before the age of 6 months.‍ Despite these figures, the recently published AAP Policy Statement, SIDS and Other Sleep-Related Infant Deaths, recommended that infants sleep in their parents’room on a separate surface, ideally for the entire first year but at least for the first 6 months.‍
The 1-year recommendation has questionable congruence with the epidemiology of SIDS (as risk is far lower after 6 months), and it runs counter to the common clinical advice parents receive. Based on evidence of improved infant sleep, clinicians may encourage parents to establish independent sleep environments (ie, in a separate room from parents) during the middle of the first year to promote healthy and sustainable sleep patterns before the typical onset of separation anxiety later in the first year.‍

The authors compared room sharing and independent sleeping to determine both sleep quantity and quality.

They found:

At 4 months, reported overnight sleep duration was similar between groups, but compared with room-sharers, early independent sleepers had better sleep consolidation (longest stretch: 46 more minutes, P = .02). At 9 months, early independent sleepers slept 40 more minutes nightly than room-sharers and 26 more minutes than later independent sleepers (P = .008). The longest stretch for early independent sleepers was 100 and 45 minutes more than room-sharers and later independent sleepers, respectively (P = .01). At 30 months, infants sleeping independently by 9 months slept >45 more minutes nightly than those room-sharing at 9 months (P = .004). Room-sharers had 4 times the odds of transitioning to bed-sharing overnight at both 4 and 9 months (P < .01 for both).

They concluded:

Room-sharing at ages 4 and 9 months is associated with less nighttime sleep in both the short and long-term, reduced sleep consolidation, and unsafe sleep practices.

That’s room sharing, but what about co-sleeping?

Sleep patterns of co-sleeping and solitary sleeping infants and mothers: a longitudinal study was published in Sleep Medicine in 2015.

Controversies exist regarding the impact of co-sleeping on infant sleep quality. In this context, the current study examined: (a) the differences in objective and subjective sleep patterns between co-sleeping (mostly room-sharing) and solitary sleeping mother-infant dyads; (b) the predictive links between maternal sleep during pregnancy and postnatal sleeping arrangement; (c) the bi-directional prospective associations between sleeping arrangement and infant/maternal sleep quality at 3 and 6 months postpartum.

They found:

 Co-sleeping infants had more reported night-wakings than solitary sleeping infants.
 Co-sleeping was not related to objective infant sleep quality.
 Co-sleeping mothers had more fragmented sleep than solitary sleeping mothers.
 Poorer maternal sleep at pregnancy and at 3 months predicted co-sleeping at 6 months.
 Breastfeeding was related to poorer maternal/infant sleep and to co-sleeping.

They concluded:

Mothers of co-sleeping infants report more infant night-wakings, and experience poorer sleep than mothers of solitary sleeping infants. The quality of maternal sleep should be taken into clinical consideration when parents consult about co-sleeping.

Breastfeeding is another factor associated with poor infant and maternal sleep.

According to the 2017 paper Exclusive breastfeeding at three months and infant sleep-wake behaviors at two weeks, three and six months:

…At three months, exclusively breastfed infants had a shorter of the longest sleep period at night than exclusively formula fed infants. At six months, exclusively breastfed infants at three months spent more hours awake at night than partially breastfed infants, awake more at night than exclusively formula fed infants, and had a shorter sleep period at night than partially breastfed and exclusively formula fed infants. This study showed differences in sleep-wake behaviors at two weeks, three and six months, when exclusively breastfed infants are compared with partially breastfed and exclusively formula fed infants at three months, while no effects were found for sleep arrangements, depression or anxiety.

Similarly, Sleep Patterns As A function of Breastfeeding: From Infancy to Childhood, published in 2018, showed:

There was a significant interaction between breastfeeding status at 6 months and age, on the longest consecutive sleep period (p<0.001). At 6 and 12 months, breastfed infants had a shorter longest consecutive sleep period than non-breastfed infants, (6:15 ± 2:49 vs 7:56 ± 2:49, p <0.001; 7:26 ± 3:16 vs 8:51 ± 2:52, p <0.001), with no difference at 24 and 36 months (p>0.05). There was no interaction between breastfeeding and age on total nocturnal sleep duration (p>0.05).

It’s long been known that exclusive breastfeeding leads to more fragmented infant sleep and therefore poorer quality sleep for mothers. Co-sleeping and room sharing, far from ameliorating the problem, actually make it worse.

Every women should decide for herself how she will feed her infant and where her baby will sleep, but new mothers deserve to know that breastfeeding, co-sleeping and room sharing lead to poorer quantity and quality of their sleep.