Anthropological evidence
Anthropological evidence of cosleeping societies is abundant. In reviews of literature on cosleeping societies Thevenin (1987) and Lozoff and Brittenham (1979) noted classic studies which included nearly 200 cultures, all of which practiced mother-infant cosleeping even if in some cultures the sleeping location of the father was separate. Examples of cultures included in the studies were the Japanese, the Korean, the Phillipino, the Eskimo Indian, the !Kung San of Africa, and the natives of Okinowa (Lozoff & Brittenham, 1979; Thevenin, 1987). The description of the Okinowan Indian culture included observations both of parent-child cosleeping until the age of six and unrestricted breastfeeding, as well as of characteristics of adult behavior that are very consistent with secure attachment histories (Thevenin, 1987). Cosleeping is the cultural norm for approximately 90% of the world’s population (Young, 1998).

An interesting contrast to the abundant anthropological evidence of cosleeping is the Israeli kibbutz practice of communal nurseries. In Israeli traditional kibbutz communities, infants are raised sleeping in communal nurseries starting at age six weeks. In a study of the influence on such a sleeping arrangement on infant-mother attachment Sagi, van Ijzendoorn, Aviezer, Donnell, and Mayseless (1994) found the rate of secure attachment was diminished significantly by infants sleeping in kibbutz infant houses instead of in their parents’ homes. In their study of 48 healthy infants, all infants spent nine hours a day, six days a week in small groups with a professional caregiver. All infants also went home for four hours during dinner time, from approximately 4 to 8 P.M. The infants in the kibbutzim with home-based sleeping would then spend the overnight hours in the care of their parents while the communal sleeping kibbutzim babies were returned to the infant houses to be put to sleep and watched overnight by two women who were monitoring several children’s houses from a central location and were responsible for upwards of 50 children between the ages of 6 weeks and 12 years. These “watchwomen” were kibbutz community members who served in this capacity for one week every six months on a rotating basis and were thus never consistently familiar to the infants. Background data with regards to quality of day care experiences, mothers’ biographical characteristics, mothers’ job satisfaction levels, and infants characteristics were considered essentially the same in both groups. The sole difference tested was the kibbutz sleeping arrangements. Within the kibbutz home-based infants, 80% were classified as having secure attachment relationships with their mothers, while among the communally-sleeping infants, only 48% demonstrated secure attachment relationship with their mothers. Although this has no direct relationship to cosleeping per se, it is likely that the primary reason the home-based babies had a higher rate of security was because of the consistency of their caregiver, who was by definition more able to respond to them quickly than the watchwomen.

Physical safety

In May 1999, the Consumer Product Safety Commission [CPSC] released a warning against cosleeping or putting babies to sleep on adult beds that was based on a study of death reports of children under the age of two who had died from 1980 to 1997. Among the 2,178 deaths by unintentional strangulation in the Commission’s study were 180 young children who had died from being overlain on a sofa or bed. In another analysis of CPSC data it was found that of 515 deaths in an adult bed, 121 of these were the result of overlying and 394 children died as a result of entrapment in the structure of the bed (Heinig, 2000). The CPSC statistics resulted in a media frenzy discouraging cosleeping which, instead of educating the public on how to share sleep safely, chose to alarm parents. Neither media announcement mentioned the 2,700 infants that died in the final year of that study of Sudden Infant Death Syndrome [SIDS], formerly called “crib death”; the vast majority of those infants died alone in their cribs (Seabrook, 1999). Meanwhile, it is interesting to note that the CPSC media announcements did not release data regarding risk factors other than sleeping location, such as whether the overlying adult was under the influence of alcohol or drugs or whether the sleeping surface was appropriate; 79 of the 515 deaths occurred on waterbeds (Seabrook, 1999). Parents must observe safety guidelines for cosleeping, just as they would for picking out a crib.

Safety while cosleeping is of utmost importance. Parents should take very seriously the importance of providing their babies with a safe sleeping environment. There are many guidelines, most of which are common sense (Sears, 1995b; Thevenin, 1987). To start with, the bed must be arranged in such a way as to eliminate the possibility of the child falling out. This can be done using a mesh guardrail, a special cosleeper crib (with three sides), or by pushing the bed flush against the wall, making sure there are no crevices which could entrap the baby. Next, in the early months, parents must be sure to place the baby next to the mother rather than between the parents as fathers are not usually as aware of their infants as the mothers are at first. Cosleepers should use a large bed or a sidecar arrangement, with a three-sided crib clamped flush to the mother’s side of the bed and the mattresses set to the same level. They should avoid using heavy comforters or pillows near the infant. Babies should not be overdressed as the warmth of the mother will be shared with the child. Infants who cosleep are usually breastfed throughout the night; this is to be encouraged. Waterbeds, sofas, and other soft surfaces should not be the location for cosleeping (Heinig, 2000; Sears, 1995b; Thevenin, 1987). Most importantly, parents should not cosleep if they are seriously sleep-deprived or under the influence of drugs or alcohol. Parents who are smokers should not cosleep as secondary smoke greatly increases the risk of death from SIDS (McKenna et al., 1993; Sears, 1995b).

Sudden Infant Death Syndrome
Research on cosleeping and SIDS has resulted in remarkable new body of knowledge which many view as affirming the decision of parents to opt for the family bed. Virtually all SIDS-related infant sleep research prior to the 1980s was conducted on isolated infants in sleep laboratories. In contrast to these studies, James McKenna, a medical anthropologist, has conducted several research studies of mother-infant cosleeping. McKenna postulated that infant sleep physiology evolved in the context of cosleeping and that infant sleep cannot be fully understood without studying the infant in its normative cosleeping environment (McKenna et al., 1993).

Within Dr. McKenna’s research, cosleeping is defined as the child sleeping close enough to another to “access, respond to or exchange sensory stimuli such as sound, movement, touch, vision, gas, olfactory stimuli, CO2, and/or temperature” (McKenna et al., 1993, p. 264). McKenna believes that cosleeping also alters other risk factors of SIDS, such as dangerous bedding, environmental temperature, and infant sleeping position. Using established polysomnographic recording guidelines, McKenna recorded the sleep, breathing, and arousal patterns of mothers and their two to four month old infants cosleeping in a laboratory and also recorded the same information for infants and mothers sleeping alone in adjacent rooms for two nights and then sleeping together for a third night (McKenna et al., 1994). Preliminary findings of cosleeping research indicated that cosleeping mothers and infants had a significantly higher levels of partner-influenced arousal overlap and synchronous sleep patterns. Since there is a suspected relationship between arousal deficits in infants and some deaths from SIDS (McKenna et al., 1993; Sears, 1995b), McKenna’s hypothesis that the influence of cosleeping on the infant’s respiratory patterns, central nervous system, and cardiovascular systems may have a protective effect seems quite valid.

Intriguingly, in a 1994 study in the United Kingdom of physiological development, infant sleeping, and SIDS risk in Asian infants, Petersen and Wailoo found that although the Asian babies had several increased physiological risk factors for SIDS, the SIDS rate is much lower in this population. The authors note that perhaps this is due to the increased stimulation the infants receive as a result of Asian infant care practices. These practices include cosleeping, carrying, and other activities which involve the child more in household life (Petersen & Wailoo, 1994). SIDS rates in Asian countries, where cosleeping is often the norm, are significantly lower than those in western society (Thevenin, 1987).

Attitudes toward cosleeping
Cosleeping from birth is recommended by La Leche League International, the world’s leading breastfeeding organization (LLLI, 1997), as well as by many professional lactation consultants (Heinig, 2000). The benefits of cosleeping to the nursing couple include increased access to nursing with less disturbance of sleep for both mother and infant. According to sleep lab studies, cosleeping mothers actually nurse their infants more frequently throughout the night, but upon awaking for the morning have little recollection of those interactions. Despite frequent arousals during the cosleeping studies, the mothers reported that they got more sleep cosleeping than they did sleeping apart from their babies (McKenna et al., 1994). An additional benefit of cosleeping and unrestricted night nursing is natural child spacing, as the return to fertility for a nursing woman whose child nurses exclusively and cosleeps, can often be delayed up to a year after the birth. Cosleeping is also reported to lead to a reduction in night fears and to the fulfillment of the maternal protective instinct (Medoff & Schaefer, 1993). Many cosleeping advocates also believe that cosleeping, as a component of natural, or attachment, parenting ultimately leads to more confident and independent children (Sears, 1995a; Thevenin, 1987).

Pediatric experts in decades past have described children sleeping in the “parental bed” as having serious negative consequences on both parents and children. Child care authors and experts such as Dr. Spock, Dr. Brazelton, and Dr. Ferber admonished parents who coslept that they would be creating negative habits or sleep disorders in their children, and fostering unhealthy childhood dependency, and that cosleeping would be harmful to the parents’ marriages (Ball, Hooker, & Kelly, 1999). A misunderstanding of the nonreactive custom of cosleeping from birth compared to the reactive use of cosleeping to solve problems with older children seem to be at the root of these anti-cosleeping positions. Studies of reactive cosleeping (Lozoff, Wolf, & Davis, 1984; Rath & Okum, 1995) have found correlations between cosleeping and childhood sleep disorders and family stress, however cultural differences in Black family cosleeping and that of whites and Hispanics were significant. In the 1984 study by Lozoff, Wolf, and Davis, a representative sample of 150 mothers of six-month-old to four-year-old children were interviewed. The rate of reported sleep problems for white cosleeping children was three times that of the solitary sleepers, but the opposite was true for Black cosleepers, who had a lower rate of sleep problems than Black solitary sleepers. Cosleeping was “routine and recent” in 70% of the Black families and 35% of the white families. The results of such studies have failed to show a causal relationship between cosleeping and sleep disorders (Medoff & Schaefer, 1993). Also, the fact that the cosleeping white and Hispanic children were older than the cosleeping Black children in the Lozoff, Wolf, Davis (1984) study, suggests that there is a cultural difference in the use of cosleeping; namely the Black families were more likely to engage in nonreactive cosleeping than the white and Hispanic populations. Although significant, peer-reviewed, studies of nonreactive cosleeping are not yet available, anthropological evidence (Lozoff & Brittenham, 1979; Thevenin, 1987) and research by both Dr. McKenna (1994) and Dr. Sears (1995b) appears to support the validity of cosleeping as a worthwhile custom, especially if the mother and child are breastfeeding.

In an article in the popular magazine The New Yorker, John Seabrook (1999) describes his journey with his wife and newborn son, into the experience of cosleeping. His wife, who coslept with her own parents and who is nursing their son, intuitively desires to cosleep. The author, however, feels more comfortable following the anti-cosleeping experts. After months of sleep deprivation and many tries at teaching the baby to sleep alone, the father relents. He has, in the course of this time, visited the infamous Dr. Richard Ferber, whose sleep-training method is a Pavlovian, incremental, cry-it-out system that promises the reward of solitary all-night sleep from babies once they are “ferberized.” In the course of the interview, the author asks Dr. Ferber about cosleeping, and Dr. Ferber, who criticizes cosleeping in his widely popular 1985 book, Solve Your Child’s Sleep Problems, recants, instead saying that “there’s plenty of examples of cosleeping where it works out just fine” (Seabrook, 1999, p. 64). After this the father begins to recognize that the primary reasons most experts give for their anti-cosleeping stances is parental convenience and a vague idea about the importance of infant independence. Mr. Seabrook learns to respect the sleep patterns of his young child and he adapts, allowing the cosleeping relationship to blossom into a bonding experience which the whole family can enjoy.

Ball, Hooker, and Kelly (1999) conducted a study in the United Kingdom to determine a baseline of nonreactive cosleeping among British parents. It was believed that although cosleeping is not part of the mainstream of parenting ideology in Britain or America, and although the literature in the field is a mess of reactive and cross-cultural juxtapositions, this study would open the door to a valid discussion of the attitudes and practices of nighttime parenting. The study was conducted by enlisting expectant parents in an economically depressed community in Northern England. Parents were interviewed about expectations of infant care practices prior to the birth and then about actual infant care practices when the baby was expected to be two to four months old. Forty families completed both interviews. Both new and experienced parents were interviewed. None of the new parents anticipated cosleeping with the child although 70% of them actually did end up cosleeping with their infants at least occasionally. Mothers being interviewed following the births frequently cited the ease of breastfeeding while lying down in bed and the ease of caring for the child while cosleeping. Not surprisingly the experienced parents were more realistic in their expectations, with 35% anticipating cosleeping and 59% actually participating in cosleeping. The vast majority of the first-time mothers who coslept and all of the experienced mothers who coslept, were also breastfeeding their infants. The study revealed that despite preconceptions of cosleeping as a dangerous and rare practice, these mainstream British parents consider it an effective infant care technique and commonly engage in it.