Cosleeping is a topic that requires a lot of discussion, research, and conversation between partners, especially if you want to bedshare (ie., share a bed with your infant).
There is a lot of information available for mothers or families consisting of two biological parents, but less conventional families are often overlooked. The reason for this is because there simply has not been enough research on bedsharing safety for these families.
It can be said with certainty that it is safest for an infant to sleep solely beside his or her biological, breastfeeding mother. A breastfeeding mother develops extraordinary sensitivity to her infant’s needs during the night, even more so than the baby’s biological father—a fact that has been scientifically proven. Most of my own sleep safety research, and the research of others, has been devoted to discovering why this is true and how a breastfeeding mother-baby duo is able to bedshare more safely than any other pair.
Unfortunately, this means that we are lacking research about when and how it is safe for other parents or unrelated caretakers to sleep beside an infant, or even in the same bed as a breastfeeding mother-baby pair. There is at least one study that has shown an increased risk when bedsharing with an unrelated adult in the bed. The Chicago Infant Mortality Study, conducted by Dr. Fern Hauk., came to the following conclusion: “Bedsharing was only a risk when the infant was sleeping with people other than the parents.”
The most important factor affecting the safety of any adult sharing the bed with a mother-baby pair is whether they consider the infant’s safety their responsibility in the same way as the mother. If an unrelated partner of any gender makes it a priority to help keep the infant safe, sharing a bed should be as safe as it would be for the biological father.
The level of commitment that a person feels toward a baby actually changes their sleep routine. Studies show that if someone takes responsibility for the infant, they will wake up more frequently to check on and care for them, and that person will be more aware of their position in relation to the infant throughout the night. Other factors to consider are what kind of relationship the unrelated partner has with both the baby and the mother, and the importance that bedsharing holds to them. A loving, committed partner, who is emotionally invested in the infant’s health and well-being, my bet is, does not constitute an added risk in a bedsharing arrangement and quite potentially value added! But, here of course, is the opportunity for the government to invest in research that can actually find out should the investigation occur in a truly objective and unbiased manner, a set of conditions that thus far have escaped the research approach conducted by members of the American Academy of Pediatrics selected to make recommendations about where any and all infants should sleep.
Still, a breastfeeding mother has many additional biological safeguards affecting her sleep structure and responsiveness, making it safer for her, and not any other adult, to sleep directly beside her baby. Regardless of how committed her partner is, I would still recommend that the child sleep between the breastfeeding mother and the side of the bed, and not between two adults, at least for the majority of the night, until we have the chance to study this further.
In cases where neither partner is directly breastfeeding the infant, such as in the case of adoptive parents, it is best for the infant to sleep on a separate surface like a cosleeping sidecar or a bassinet beside the bed. This way, you can still maintain closeness, easily bottle-feed, and keep an eye out for apneas or other dangers throughout the night.
In some situations, unrelated adults might not feel the same responsibility for the child as would a biological parent. That is understandable, but in any situation where this is true, or hesitations or doubts are brought up, bedsharing is not recommended. It is best to err on the side of caution by keeping the baby on a separate surface next to the bed. The same would be true in a situation where one of the partners does not want to bedshare with the infant, does not feel confident in their ability to maintain awareness during the night, or does not agree to sleep without the use of drugs or alcohol.
Regardless of your family structure and chosen cosleeping arrangement, always follow bedsharing or crib safety guidelines.