This review aimed to better understand the underlying physiology of the risks and benefits of bed-sharing. Eight databases were searched using terms relating to adult-infant/baby, bed-sharing/co-sleeping combined with outcome terms for physiology, sleep, cardiovascular, respiratory, temperature and behaviour. Of 836 papers identified, 59 papers representing 48 cohorts met inclusion criteria. Objective data using various methodologies were available in 27 papers and subjective data in 32 papers. Diverse measures were reported using variable definitions of bed-sharing. Identified physiological and behavioural differences between bed-sharing and cot-sleeping included increased behavioural arousals, warmer in-bed temperatures and increased breastfeeding duration in bedshare infants as well as differences in infant overnight sleep architecture, cardiorespiratory control and cortisol responses to stress. We concluded that many differences are context-specific, and dependent on the subjective view of the parents and their cultural values. Objective risk arises if the infant is unable to mount an appropriate physiological or behavioural response to their micro-environment. More studies in the bed-sharing setting are needed to identify infant risk, the potential benefits of a safer environment, and how bed-sharing interacts with infant care practices other than sleep.

Introduction As mounting evidence underscores the importance of both men and women taking steps before pregnancy to improve reproductive outcomes, public health priorities are shifting toward a more gender-inclusive program of promoting preconception health (PCH). This study examined whether prescriptive gender stereotypes, defined as men's and women's beliefs about PCH behavioral norms each gender should uphold, were positively associated with intentions to engage in behaviors to protect a future child's health. Methods Data came from a June 2017 online survey of 609 U.S. men and women ages 18-44. Two six-item scales of prescriptive same- and opposite-gender stereotypes were used to predict a six-item scale of intentions to engage in six recommended PCH behaviors (i.e., avoiding smoking, secondhand smoke, drinking, exposure to bisphenol A and pesticides, and preventing Zika infection). Multiple linear regression models also adjusted for demographic, socioeconomic, and health characteristics. Results Among both male and female respondents, PCH prescriptive gender stereotypes for men were rated significantly lower than those for women. Adjusting for covariates, stronger prescriptive same-gender stereotypes were associated with increased PCH intentions (men: B = 0.496, p < 0.001; women: B = 0.486, p < 0.001). Opposite-gender stereotypes were also positively associated with PCH intentions (men: B = 0.205, p < 0.001; women: B = 0.235, p < 0.001). Current every day smoking status (men and women), being uninsured (women only), and having children (women only) were also associated with lower PCH intentions. Conclusion Prescriptive gender stereotypes may play an important, yet slightly different, role in promoting PCH behavior among men and women.