Cobedding twins or higher-order multiples is the practice of placing siblings in the same crib, bed, or incubator. Cobedding multiples in a hospital setting was first reported in the 1940s and has been the standard of care in much of Europe for more than a decade.1 Cobedding multiples in hospitals was not commonly practiced in the United States until anecdotal reports of cobedding began to appear in American newspapers in the mid-1990s.2,3 At the same time, there was growing concern about the effects of the NICU environment on infant health and development. Studies have suggested that outcomes among low birth weight infants improved when behavioral cues were used to restructure the environment and modify caregiving interventions.4–6 As a result, the practice of developmentally supportive care emerged. Proponents of cobedding multiples believe that cobedding should be a component of developmentally supportive care because it may ease transition from intrauterine to extrauterine life by allowing for the continuation of the interactive development and coregulation that may have occurred between siblings while in utero.7–14
As cobedding multiples has become more widely practiced in hospitals in the United States, the rate of multiple births has increased substantially.15 In 2004, 3.4% of all live births in the United States were multiple births. In that year, the twin birth rate reached a record high of 32.2 twin births per 1000 total live births, which represents a 42% increase from 1990 (22.6 per 1000) and a 70% increase from 1980 (18.9 per 1000). There were nearly twice as many live births in twin deliveries in 2004 as there were in 1980. The rate of higher-order multiple births in 2004 was 176.9 multiple births per 100000 total live births, which represents a 378% increase from 1980 (37.0 per 100000). Delayed childbearing resulting in older maternal age and the increased use of fertility therapies are factors that have contributed to this trend.16–20
Although multiple births make up a small proportion of all live births, twins and higher-order multiples are at an increased risk for poor birth outcomes such as preterm birth and low birth weight.21,22 Multiple-gestation infants are more likely than singletons to require neonatal intensive care and have longer hospital stays after birth. Because of this, health care providers will increasingly be faced with the issue of whether to cobed multiples in their hospitals.
The purpose of this commentary is to review the published literature on the practice of cobedding multiples in US hospitals and to inform health care providers by outlining what is known about the risks and benefits of this practice on the basis of existing evidence. A review of the published literature from 1990 through June 2006 was conducted. Searches were conducted in Medline, Cinahl, and EMBASE. The search strategy included published articles in English with the Medical Subject Headings (MeSH) “twins,” “pregnancy, multiple,” “multiple birth offspring,” “intensive care units, neonatal,” “asphyxia neonatorum,” “asphyxia,” and “sudden infant death” and the key words “co-bedding,” “cobedding,” “bed sharing,” “bedsharing,” “co-sleeping,” “cosleeping,” “sleeping with sibling,” “multiple gestation infants,” “NICU,” and “SIDS.” The search identified 8 articles in Medline, 16 in Cinahl, and none in EMBASE. All were studies that involved human subjects. We included in this review all articles that reported a descriptive or analytic study.
A majority of published articles on cobedding multiples have been anecdotal reports,23–28 short commentaries,1,29,30 and literature reviews.31–33 We found 10 articles that described cobedding studies that were conducted in NICUs; 2 were descriptive studies,34,35 and 8 were analytic studies,36–44 3 of which had experimental designs36,40,41,44 (Table 1).
REPORTED BENEFITS OF COBEDDING MULTIPLES IN A HOSPITAL SETTING: ANECDOTAL REPORTS AND DESCRIPTIVE STUDIES
Anecdotal reports and observational studies have suggested that cobedding may have beneficial physiological and psychological effects on infants.23–28,34,35 Specifically, the reported observed benefits of cobedding multiples include stabilization of vital signs and improved regulation of body temperature,2,3,24,25,28 enhanced growth and development,24,25 and a decrease in the number of episodes of apnea and bradycardia.26 In addition, multiples have been observed to be more relaxed and less agitated28,35 and to have more sleep/wake synchronicity while cobedding.35 Proposed benefits include easier transition to home,23 decreased length of hospital stay,25,28 and fewer rehospitalizations.25
REPORTED BENEFITS OF COBEDDING MULTIPLES IN A HOSPITAL SETTING: ANALYTIC STUDIES
Three of the 8 analytic studies did not provide any evidence that cobedding multiples in the hospital improves physiological or psychological outcomes among these infants when compared with separately bedded multiples.37,38,40,41 In addition, 2 analytic studies concluded that although they found statistically significant differences between cobedded and separately bedded multiples, the findings were either “not clinically significant” or likely to be “spurious.”36,43 However, these studies were limited by their small sample size and lack of long-term follow-up.
Four of the analytic studies examined differences between cobedded and separately bedded multiples in clinical outcomes such as length of hospital stay, incidence of specific nosocomial infections, and number of evaluations to “rule out” sepsis.37,41–43 Only 1 of these studies, a large retrospective study, found a significant difference in clinical outcomes between 94 cobedded and 112 separately bedded preterm twins of 23 to 35 weeks’ gestation.42 Cobedded twins had fewer positive blood-culture results during their hospitalization than separately bedded twins (3 [3.2%] vs 5 [4.5%]; P = .043).42 Although this was the largest analytic study on cobedding to date, it was limited by the small sample size and the fact that the authors collected data from day 7 of life until time of discharge for both groups instead of from the time of initiation of cobedding until discharge for the cobedded group. This is problematic, because infants of 23 to 26 weeks’ gestation started cobedding at a mean of 65 days after birth, infants of 27 to 30 weeks’ gestation at 37 days, and infants of 31 to 35 weeks’ gestation at 13 days. A smaller prospective study that compared rates of nosocomial infection and number of evaluations for sepsis between 56 cobedded and 60 separately bedded preterm twins or higher-order multiples resulted in no significant differences between the 2 groups.40,41
An article that described a prospective cohort of 31 cobedded multiples and 31 separately bedded multiples matched for gestational age and size at birth reported that cobedded infants were placed in an open crib 6.4 days sooner than controls and their mean length of stay was 3.2 days fewer than controls. However, neither result reached statistical significance.43 Another retrospective study of all multiples admitted to an NICU over a 26-month period found no significant differences in clinical outcomes such as length of hospital stay, number of days to full nipple feeding, and number of days in an incubator between 39 cobedded and 116 separately bedded multiples.37
Weight Gain and Growth
Of the 5 analytic studies that examined differences in weight gain and growth between cobedded and separately bedded multiples,36,37,40,41,43,44 2 experimental studies suggested that cobedded multiples may gain weight more readily than separately bedded multiples.36,44 Researchers who performed a small prospective, randomized study that compared 16 cobedded and 21 separately bedded infants found that cobedded infants had a higher 5-day average daily weight gain.36 However, the authors concluded that the average daily weight gain between the 2 groups, although statistically significant, was not clinically important. Another prospective, randomized study that compared outcomes between 42 cobedded and 40 separately bedded multiples showed a significantly higher average weekly weight gain among cobedded infants during the first 2 weeks of the study but not during the third week of the study.44 A third prospective, randomized study that compared outcomes between 56 cobedded and 60 separately bedded preterm twins or higher-order multiples found no significant differences between the 2 groups’ average weekly weight gain or growth.40,41
Of the 4 analytic studies that examined differences in physiological stress between cobedded and separately bedded multiples,36,38,39,43 1 study found statistically significant differences between the 2 groups.36 The small prospective, randomized study found no significant differences in baseline or activity heart rate, respiratory rate, oxygen saturation, or stress cues between 16 cobedded multiples and 21 separately bedded multiples over a 5-day period.36 However, cobedded multiples had lower high-activity heart rates for the last 3 days of the study, which the authors hypothesized may reflect a decrease in stress. Findings from a small study that examined responses of low birth weight twins to episodes of cobedding followed by separation suggest that twins have lower stress and higher self-regulatory behaviors when they are cobedded and wrapped together with 1 swaddling cloth than when they are separated.38 Twins with more exposure to cobedding had the lowest stress and the highest self-regulatory behaviors when cobedded. However, none of these findings were statistically significant.
Apnea and Bradycardia
Three of the analytic studies examined differences in apnea and bradycardia between cobedded and separately bedded multiples.39,43,44 One blinded study that compared event recordings from cardiorespiratory monitors of 22 preterm twins for 12 hours before and the first 12 hours of cobedding found that there were significantly fewer episodes of central apnea (defined as a pause in respiration of >10 seconds) during cobedding.39 When the definition of apnea was extended to >15 seconds, however, no significant difference was found. The authors hypothesized that this decrease in apnea of 10 to 15 seconds may be have been caused by more frequent arousal, resulting in a more regular respiratory pattern. Alternatively, the decrease in apnea may have reflected a positive physiological response to physical contact. The authors did not find any significant difference in the number of events of bradycardia, periodic breathing, or central apnea associated with bradycardia or any significant differences in the mean heart rate, respiratory rate, or blood pressure before and during cobedding.39 A small prospective, randomized study that compared the median number of apnea, bradycardia, and desaturation episodes between cobedded and separately bedded multiples found no difference between the groups.44 The study defined apnea as cessation of breathing for >20 seconds. Last, a study of a prospective cohort of 31 cobedded multiples and 31 separately bedded multiples matched for gestational age and size at birth found no differences in number of apneic episodes or the incidence of periodic breathing between the 2 groups of infants.43
PARENTAL ATTITUDES TOWARD COBEDDING IN A HOSPITAL SETTING
Of the anecdotal reports and observational studies of parental attitudes toward cobedding multiples, most reported that parents supported the practice.23–28,34,35 Specifically, the authors observed that parents felt an increased sense of control over the care of their infants23 and valued having their family together, supported by a nurse.28 Proposed benefits included improved parent-infant bonding23,25 and improved nurse-parent communication.25
Of the 4 analytic studies that examined parental attitudes toward cobedding, the results were mixed.36–38,41 The small prospective randomized study of 16 cobedded and 21 separately bedded multiples did not find any differences in parental anxiety, maternal attachment, or parental satisfaction between groups.36 In contrast, in a study by Lutes and Altimier,41 exit interviews found that parents approved of cobedding, stating that it improved communication and decreased the number of staff needed to care for the infants. In another study, Stainton et al38 found that parental attitudes toward cobedding changed from initial uncertainty to preference for cobedding, with all parents continuing to cobed their twin infants for 3 weeks to 9 months (mean: 5.5 months) after hospital discharge. A fourth study showed a low response rate (ie, 55% of eligible parents with valid addresses) to the parental survey; therefore, those results should be interpreted with caution.37
REPORTED RISKS OF COBEDDING MULTIPLES IN A HOSPITAL SETTING: ANECDOTAL REPORTS AND DESCRIPTIVE STUDIES
Anecdotal reports and observational studies have raised concerns about the potential risks of cobedding multiples in the NICU.23–28,34,35 Observed risks included temperature instability and hypothermia among the smaller twin or multiples,23–25 increased length of stay for the healthier infant because of a parent's refusal to separate cobedded multiples,23 infants’ incompatibility with each other,24,25 and infection.24,25 In addition, researchers in 1 institution noted that cobedding increases the level of complexity and difficulty of performing procedures and routine care.24,25 Proposed risks included accidental disruption of therapy,23 an increased potential for medical errors,23–25 unnecessary exposure to supplemental oxygen,23 increased risk of infection,23 sleep disruption of an infant by the sibling, and dislodging feeding tubes, monitor leads, or temperature probes.
REPORTED RISKS OF COBEDDING MULTIPLES IN A HOSPITAL SETTING: ANALYTIC STUDIES
None of the analytic studies that we reviewed found cobedding multiples to be associated with an increased risk for poor outcomes. However, these studies were limited because of their small sample sizes. A prospective cohort study of 31 cobedded multiples and 31 separately bedded multiples matched for gestational age and size at birth found that cobedded infants had a significantly greater number of temperature decreases than separately bedded multiples, a finding the authors concluded was “likely a spurious result.”43 A small prospective, randomized study of 56 cobedded and 60 separately bedded preterm twins or higher-order multiples found no difference in the number of nosocomial infections, sepsis evaluations, or thermal insults between the 2 groups.41 In that study, 1 medication error (a missed dose of medication) occurred among the cobedded-infant group. Last, in the largest study to date, the authors found no significant difference in the number of sepsis evaluations or in the incidence of pneumonia or necrotizing enterocolitis between 94 cobedded and 112 separately bedded preterm twins of 23 to 35 weeks’ gestation.42 However, as mentioned above, the study had limitations.
IMPLICATIONS OF COBEDDING MULTIPLES AFTER HOSPITAL DISCHARGE
Some health care providers are concerned that cobedding multiples in the hospital encourages parents to cobed infants at home after hospital discharge.29,30 By cobedding multiples, hospital staff may be sending a message to parents that this practice is not only beneficial but that it is safe when implemented in the home environment. Two studies have suggested that hospital sleep practices may predict sleeping arrangements at home.
A study that compared outcomes between cobedded and separately bedded multiples in the hospital found that cobedded multiples were significantly more likely than separately bedded multiples to be cobedded after hospital discharge.37 In another study, all study participants who were cobedded in the hospital were cobedded at home for an average of 5.5 months after discharge.38
Although research on the safety or benefits of cobedding multiples in hospitals (as reviewed above) is limited, no research has supported the safety of cobedding multiples at home. One case-control study of sudden infant death syndrome (SIDS) examined the risk of infants sharing a sleep surface with another person.45 The authors found that infants who slept with other children alone or with children and 1 or both parents had a fourfold increased risk of SIDS (odds ratio: 4.1 [95% confidence interval: 2.0–8.4]). Although the risk of SIDS among cobedded multiples remains unknown, many multiples are at increased risk for SIDS because they are born preterm. Compared with multiples who sleep in separate beds, multiples who are cobedded theoretically may be at increased risk of SIDS because of overheating35 and rebreathing each others’ carbon dioxide. A discordance in size or weight of the multiples may also increase their risk of accidental suffocation when cobedded. In addition, cobedding multiples at home may be difficult for parents, because twins and higher-order multiples are not likely to be on the same feeding schedule, and waking 1 infant to feed may disturb the sleep pattern of the other infant(s), resulting in more crying and restlessness, less sleep, and added parental stress.1,25
Although cobedding multiples has become more widely practiced in hospitals in the United States, neither the safety nor the benefit of this practice has been documented in the published literature. Parents should be encouraged to follow established safe-sleep practices for infants at home.46
AREAS FOR FURTHER RESEARCH
Future analytic studies should be designed with adequate power (ie, sufficient sample size) so that if differences in outcomes truly exist between cobedded and separately bedded multiples, they can be detected.
Future data collection on all sudden, unexplained infant deaths, including those attributed to SIDS, should include determining whether twins or higher-order multiples were cobedded with a same-aged sibling at the time of their last sleep.
Committee on Fetus and Newborn, 2005–2006
Ann R. Stark, MD, FAAP, Chairperson
David H. Adamkin, MD, FAAP
Daniel Gene Batton, MD, FAAP
Edward F. Bell, MD, FAAP
Susan Ellen Denson, MD, FAAP
William Allan Engle, MD, FAAP
Gilbert Ira Martin, MD, FAAP
Jim Couto, MA
Kay Marie Tomashek, MD, MPH, FAAP
Centers for Disease Control and Prevention
Carol Wallman, MSN, NNP, RNC
National Association of Neonatal Nurses and Association of Women's Health, Obstetric, and Neonatal Nurses
Vinod K. Bhutani MD, FAAP
Tonse N.K. Raju, MD, DCH, FAAP
National Institute of Child Health and Human Development
Gary Hankins, MD
American College of Obstetrics and Gynecology
We thank William (Bill) Thomas of the Centers for Disease Control and Prevention for conducting the literature review and providing assistance in locating references.
- Accepted June 19, 2007.
- Address correspondence to Kay Marie Tomashek, MD, MPH, FAAP, US Public Health Service, Epidemiology Activity, Dengue Branch, Division of Vector-Borne Infectious Disease, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, Puerto Rico 00920. E-mail:
The authors have indicated they have no financial relationships relevant to this article to disclose.
Opinions expressed in these commentaries are those of the author and not necessarily those of the American Academy of Pediatrics or its Committees.
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- ↵Gannon J. From womb mates to roommates: co-bedding in the NICU. Nurs Spectr (Gt Chic Ne Ill Nw Indiana Ed).1999;12 :22
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- ↵Armpriester T. Co-bedding twins/multiples together. J Newborn Nurs.1999;2 :9
- ↵Bingham R. The blue pages: let's spend the night together—co-bedding. J Neonatal Nurs.1997;16 :54
- ↵Boyd S. “The way they were”: multiple gestation infants and co-bedding. J Neonatal Nurs.2001;7 :95– 100
- ↵LaMar K, Taylor C. Incidence of infection for cobedded preterm twin infants. J Neonatal Nurs.2004;10 :197– 200
- ↵Stainton C, Jozsa E, Fethney J. Responses to co-bedding of low birth weight twins in neonatal intensive care. Neonatal Paediatr Child Health Nurs.2005;8 :4– 12
- ↵Touch SM, Epstein ML, Pohl CA, Greenspan JS. The impact of cobedding on sleep patterns in preterm twins. Clin Pediatr (Phila).2002;41 :425– 431
- ↵Lutes LM, Altimier L. Co-bedding twins and higher-order multiples. Central Lines.2000;16 :10– 13
- ↵Longobucco D, Bernstein B, Rossi D. To cobed or not to cobed? A comparative study of cobedded versus individually bedded multiple birth infants in the NICU. Pediatr Res.2000;47 :413
- ↵Hauck FR, Herman SM, Donovan M, et al. Sleep environment and the risk of sudden infant death syndrome in an urban population: the Chicago Infant Mortality Study. Pediatrics.2003;111(5 pt 2) :1207– 1214
- ↵American Academy of Pediatrics, Task Force on Sudden Infant Death Syndrome. The changing concept of sudden infant death syndrome: diagnostic coding shifts, controversies regarding the sleeping environment, and new variables to consider in reducing risk. Pediatrics.2005;116 :1245– 1255
- Copyright © 2007 by the American Academy of Pediatrics