Four modifiable and other major risk factors for cot death: the New Zealand study

The continuing decline in SIDS mortality

The "Back to Sleep" campaign resulted in a dramatic decrease in sudden infant death syndrome (SIDS) worldwide. SIDS mortality has continued to decline (in New Zealand by 63% from 1993 to 2004), but the reason for this has not been explained. A postal survey found that the proportion of infants sleeping on their back has increased substantially (from 24.4% in 1992 to 72.3% in 2005), and this could account for the 39%-48% decrease in SIDS mortality.

Do immunisations reduce the risk for SIDS? A meta-analysis

BACKGROUND

There are claims that immunisations cause sudden infant death syndrome (SIDS), but some studies have found either no association or that they are associated with a reduced risk of SIDS.

AIMS

To conduct a meta-analysis examining the relationship between immunisation and SIDS.

METHODS

Nine case-controls studies were identified examining this association, of which four adjusted for potential confounders.

RESULTS

The summary odds ratio (OR) in the univariate analysis suggested that immunisations were protective, but the presence of heterogeneity makes it difficult to combine these studies. The summary OR for the studies reporting multivariate ORs was 0.54 (95% CI=0.39-0.76) with no evidence of heterogeneity.

CONCLUSIONS

Immunisations are associated with a halving of the risk of SIDS. There are biological reasons why this association may be causal, but other factors, such as the healthy vaccinee effect, may be important. Immunisations should be part of the SIDS prevention campaigns.

Infant sleep position, head shape concerns, and sleep positioning devices

AIM

The Back To Sleep campaign has successfully promoted the use of the supine sleep position for infants, with a corresponding decrease in sudden infant death syndrome death rates around the world. The aim of this study was to survey current infant sleep position practices, concerns about plagiocephaly, and the use of sleep positioning devices.

METHODS

A postal survey of 400 mothers of infants aged 6 weeks to 4 months was carried out in Auckland, New Zealand.

RESULTS

Of the 278 (69.5%) respondents, the supine position was usually used in 64.8%, the prone position in 2.9%, with 32.3% using the side position or a combination of side and back positions. Approximately one-third had a concern about their infant's head shape, and 80% described practices to help prevent head deformation. Thirty per cent reported they had changed their infant's sleep position because of head shape concerns. A third of the mothers used some sort of positioning system to maintain the infant's sleep position.

CONCLUSIONS

Anxieties about plagiocephaly, aspiration of vomit, and poor quality sleep are the main concerns that parents have about sleeping their infants on their backs. Further education is needed to inform mothers about these issues and to alleviate their fears.

Do risk factors differ between explained sudden unexpected death in infancy and sudden infant death syndrome?

BACKGROUND

In Germany, 2910 infants died in 2004; for many infants the reason was clear, especially prematurity or congenital abnormalities. However, 394 babies die every year suddenly and unexpectedly. The cause may be immediately clear, but is often not obvious.

AIMS

(1) To describe the causes of explained sudden unexpected death in infancy (SUDI) and (2) to compare risk factors for sudden infant death syndrome (SIDS) and explained SUDI.

METHODS

A 3-year population-based case-control study in Germany, 1998-2001.

RESULTS

455 deaths, of which 51 (11.2%) were explained. Most of these deaths were due to respiratory or generalised infections. The risk factors for SIDS and explained SUDI were remarkably similar except for sleep position and breast feeding. Prone sleeping position is a major risk factor for SIDS (adjusted odds ratio (OR) 7.16, 95% confidence interval (CI) 3.85 to 13.31) but not for explained SUDI (adjusted OR 1.71, 95% CI 0.25 to 11.57). Not being breast fed in the first 2 weeks of life is a risk factor for SIDS (adjusted OR 2.37, 95% CI 1.46 to 3.84) but not for explained SUDI (adjusted OR 0.39, 95% CI 0.08 to 1.83).

CONCLUSIONS

Prone sleeping position is a unique risk factor for SIDS. Socioeconomic disadvantage and maternal smoking are risk factors for both SIDS and explained SUDI, and provide an opportunity for targeted intervention.

Sleep arrangements and behavior of bed-sharing families in the home setting

OBJECTIVES

We aimed to provide a quantitative analysis of the sleep arrangements and behaviors of bed-sharing families to further understand the risks and benefits as well as the effects of infant age and room temperature on bed-sharing behaviors.

METHODS

Forty infants who regularly bed shared with > or = 1 parent > or = 5 hours per night were recruited. Overnight video of the family and physiological monitoring of the infant was conducted in infants' homes. Infant sleep position, potential for exposure to expired air, head covering and uncovering, breastfeeding, movements, family sleep arrangements, responses to the infant, and interactions were logged.

RESULTS

All infants slept with their mother. Fathers were included in 18 studies and siblings in 4. Infants usually slept beside the mother, separated from the father/siblings (if present), facing the mother, with head at mothers' breast level, touching, or with mother cradling. Median overnight breastfeeding duration was 40.5 minutes. Mothers commonly faced their infant, but infants were rarely in a position that potentially exposed them to maternal expired air. Fathers were seldom in contact with the infant during sleep. Of the 102 head-covering episodes observed in 22 infants, 80% were because of changes in adult sleep position. Sixty-eight percent of head uncovering was facilitated by the mother; half of these events were prompted by the infant. A 1 degree C increase in room temperature decreased infant head covering by 0.2 hours.

CONCLUSIONS

The mother-infant relationship is of prime importance during bed sharing, whether the father is present or not. The focus around breastfeeding often dictates the sleep position of the infant and mother, though room temperature may also influence this. In colder rooms infants tend to spend more time with their face covered by bedding. Frequent maternal interactions rely on the ability of the mother to arouse with little stimulation. Mothers, perhaps impaired by alcohol, smoking, or overtiredness, may not be able to respond appropriately.

Breastfeeding and the cultural configuration of social space among Vietnamese immigrant woman

This study aimed to identify cultural factors involved in the abandonment of breastfeeding amongst Vietnamese immigrant women in Canada. Qualitative interviews were conducted with 19 mothers, exploring their perinatal experience from Vietnam to Canada. The results suggest that the decision to bottle-feed was not related to acculturation to local practices as has been claimed in previous studies but to conflicts between Vietnamese cultural practices and the configuration of the new social space in Canada. Living in Canada did not allow specific family members to conduct postnatal traditional rituals thus jeopardizing mothers' perceived health and the quality of their milk. Culturally appropriate strategies to promote breastfeeding among migrants must consider the social and spatial organization of cultural practices.

Smoking and the sudden infant death syndrome

The aims of this review are (a) to critically examine the epidemiologic evidence for a possible association between smoking and the sudden infant death syndrome (SIDS), (b) to review the pathology and postulated physiological mechanism(s) by which smoking might be causally related to SIDS, and (c) to provide recommendations for SIDS prevention in relation to tobacco smoking. Over 60 studies have examined the relation between maternal smoking during pregnancy and risk of SIDS. With regard to prone-sleep-position intervention programs, the pooled relative risk associated with maternal smoking was RR = 2.86 (95% CI = 2.77, 2.95) before and RR = 3.93 (95% CI = 3.78, 4.08) after. Epidemiologically, to distinguish the effect of active maternal smoking during pregnancy from involuntary tobacco smoking by the infants of smoking mothers is difficult. Clear evidence for environmental tobacco smoke exposure can be obtained by examining the risk of SIDS from paternal smoking when the mother is a non-smoker. Seven such studies have been carried out. The pooled unadjusted RR was 1.49 (95% CI = 1.25, 1.77). Consideration of the pathological and physiological effects of tobacco suggests that the predominant effect from maternal smoking comes from the in utero exposure of the fetus to tobacco smoke. Assuming a causal association between smoking and SIDS, about one-third of SIDS deaths might have been prevented if all fetuses had not been exposed to maternal smoking in utero.

Are the risk factors for SIDS different for preterm and term infants?

BACKGROUND

Mortality from SIDS has declined since the recommendation that infants are not placed prone to sleep. SIDS mortality is higher in infants born preterm than those born at term.

AIM

To determine if risk factors for SIDS are any different for preterm and term infants.

METHODS

Mortality data over time were used to determine whether the reduction in SIDS mortality rates had occurred equally in term and preterm infants. Data from two New Zealand studies (a case-control study and a case-cohort study) were used to determine if any differences existed in risk factors for SIDS between term and preterm infants before and after the SIDS prevention campaign.

RESULTS

SIDS mortality appears to have decreased by similar proportions in term and preterm infants. Risk factors for SIDS were similar in preterm and term infants, except for parity where there was a significant interaction. Increasing parity was a risk factor for SIDS in term infants but not preterm infants.

CONCLUSION

SIDS rates have decreased at comparable rates in term and preterm infants, but preterm birth still remains a risk factor for SIDS. The magnitude of the odds ratios associated with modifiable risk factors were similar for both groups. There may however be a difference in risk associated with parity between term and preterm infants. The messages for risk factors for SIDS are applicable to mothers of preterm as well as term infants.

Bedsharing and maternal smoking in a population-based survey of new mothers

OBJECTIVE

Sudden infant death syndrome (SIDS) remains the number 1 cause of postneonatal infant death. Prone infant sleep position and maternal smoking have been established as risk factors for SIDS mortality. Some studies have found that bedsharing is associated with SIDS, but, to date, there is only strong evidence for a risk among infants of smoking mothers and some evidence of a risk among young infants of nonsmoking mothers. Despite the lack of convincing scientific evidence, bedsharing with nonsmoking mothers remains controversial. In some states, nonsmoking mothers are currently being told that they should not bedshare with their infants, and mothers of infants who died of SIDS are told that they caused the death of their infant because they bedshared. The objective of this study was to explore the relationship between maternal smoking and bedsharing among Oregon mothers to explore whether smoking mothers, in contrast to nonsmoking mothers, are getting the message that they should not bedshare.

METHODS

Oregon Pregnancy Risk Assessment Monitoring System surveys a stratified random sample, drawn from birth certificates, of women after a live birth. Hispanic and non-Hispanic black, non-Hispanic Asian/Pacific Islander and non-Hispanic American Indian/Alaskan Native women, and non-Hispanic white women with low birth weight infants are oversampled to ensure sufficient numbers for stratified analysis. The sample then was weighted to reflect Oregon's population. In 1998-1999, 1867 women completed the survey (73.5% weighted response). The median time from birth to completion of the survey was 4 months. Women were asked whether they shared a bed with their infant "always," "almost always," "sometimes," or "never." Frequent bedsharing was defined as "always" or "almost always"; infrequent was defined as "sometimes" or "never."

RESULTS

Of all new mothers, 35.2% reported bedsharing frequently (always: 20.5%; almost always: 14.7%) and 64.8% infrequently (sometimes: 41.4%; never: 23.4%). Bedsharing among postpartum smoking mothers was 18.8% always, 12.6% almost always, 45.1% sometimes, and 23.6% never; this was not statistically different from among nonsmoking mothers. Results for prenatal smokers were similar. When stratified by race/ethnicity, there was no association between smoking and bedsharing in any racial or ethnic group. In univariable and multivariable logistic regression, there were no statistical differences in frequent or any bedsharing among either prenatal or postpartum smoking mothers compared with nonsmokers; the adjusted odds ratio for postpartum smokers who frequently bedshared was 0.73 (95% confidence interval [CI]: 0.42-1.25) and for any bedsharing was 1.05 (95% CI: 0.57-1.94). Results for prenatal smoking were similar. This is the first US population-based study to look at the prevalence of bedsharing among smoking and nonsmoking mothers. Bedsharing is common in Oregon, with 35.2% of mothers in Oregon reporting frequently bedsharing and an additional 41.4% sometimes bedsharing. There was no significant association between smoking and bedsharing for either prenatal or postpartum smokers among any racial or ethnic group. Smoking mothers were as likely to bedshare as nonsmoking mothers. The frequency of bedsharing in Oregon was similar to estimates from other sources. Our study has the advantage of being a population-based sample drawn from birth certificates, weighted for nonresponse.

CONCLUSIONS

Although a number of case series have raised concerns about the safety of mother-infant bedsharing, even among nonsmoking mothers, this has not yet been confirmed by careful, controlled studies. There have been 9 large-scale case-control studies of the relationship between bedsharing and SIDS. Three case-control studies did not stratify by maternal smoking status, but found no increased risk for SIDS. Six case control studies reported results stratified by maternal smoking status: 1 study, while asserting an association, provided an unexplained range of univariable odds ratios without CIs; 3 found no increased risk for older infants of nonsmoking mothers; and 2 found a risk only for infants <8-11 weeks of age. Despite the preponderance of evidence that bedsharing by nonsmoking mothers does not increase the risk for SIDS among older infants, the recent specter of bedsharing as a cause of SIDS, based on uncontrolled case series and medical examiners' anecdotal experience, has led some medical examiners to label a death "suffocation" or "overlay asphyxiation" simply because the infant was bedsharing at the time of death. This "diagnostic drift" may greatly complicate future studies of the relationship between bedsharing and SIDS. Epidemiologic evidence shows that there is little or no increased risk for SIDS among infants of nonsmoking mothers but increased risk among infants of smoking mothers and younger infants of nonsmoking mothers. It seems prudent to discourage bedsharing among all infants <3 months old. Young infants brought to bed to be breastfed should be returned to a crib when finished. It would be worthwhile for other researchers to reanalyze their previous data to evaluate the consistency of the interaction of young infant age and bedsharing. Large controlled studies that include infants who are identified as dying from SIDS, asphyxia, suffocation, and sudden unexplained infant death, analyzed separately and in combination, are needed to resolve this and other issues involving bedsharing, including the problem of diagnostic drift. Recommendations must be based on solid scientific evidence, which, to date, does not support the rejection of all bedsharing between nonsmoking mothers and their infants. Cribs should be available for those who want to use them. Nonsmoking mothers should not be pressured to abstain from bedsharing with their older infants; they should be provided with accurate, up-to-date scientific information. Infants also should not co-sleep with nonparents. In Oregon, if not elsewhere, the message that smoking mothers should not bedshare is not being disseminated effectively. Because it is not known whether the risk caused by smoking is associated with prenatal smoking, postpartum smoking, or both, bedsharing among either prenatal or postpartum smokers should be strongly discouraged. Much more public and private effort must be made to inform smoking mothers, in culturally competent ways, of the very significant risks of mixing bedsharing and smoking. Public health practitioners need to find new ways to inform mothers and providers that smoking mothers should not bedshare and that putting an infant of a nonsmoking mother to sleep in an adult bed should be delayed until 3 months of age.

Acute idiopathic pulmonary haemorrhage in infancy: case report and review of the literature

This report presents the case of a 4-month-old male infant with recurrent bouts of haemoptysis for which no cause could be detected after extensive investigation. Literature reports of this condition from other geographic locations around the world are reviewed, together with epidemiologic studies attempting to provide a link with certain environmental exposures, toxic and infectious. A diagnostic entity of acute idiopathic pulmonary haemorrhage in infancy has recently been proposed. To my knowledge, this is the first case reported from New Zealand. Although the incidence of such reported cases appears to be rare, they constitute an interesting public health problem, particularly because some of the risk factors appear to overlap with risk factors for sudden infant death. They can therefore trigger an investigation into the home and outdoor environments, and may provide valuable insights into a possible underlying genetic factor and potentially harmful exposures in the modern urban or rural settings.

Pulmonary aspiration of gastric contents and the sudden infant death syndrome

OBJECTIVE

To determine ante-mortem and post-mortem risk factors for the finding of gastric contents in pulmonary airways (aspiration of gastric contents) at post-mortem examination in the sudden infant death syndrome (SIDS).

METHODS

There were 217 post-neonatal deaths in the Auckland region of the New Zealand Cot Death Study. No deaths were certified as due to aspiration of gastric contents. There were 138 SIDS cases. The parents of 110 (80%) of these cases were interviewed. Histological sections from the periphery of the lungs in 99 of the 110 cases were reviewed for evidence of aspiration of gastric contents. A wide range of variables were analysed in SIDS cases with and without aspiration to determine risk factors.

RESULTS

Aspiration of gastric contents was identified in 37 (37%) of SIDS cases. Aspiration was of mild-to-moderate degree and in no case was severe and a potential cause of death. Finding infants on their backs at death (P = 0.024) and conducting the post-mortem on the day after the death or subsequently (P = 0.033) were statistically significant variables linked to identification of aspiration. Position placed to sleep, symptoms of gastro-oesophageal reflux and other variables were not related to aspiration.

CONCLUSIONS

The only determinants for aspiration of gastric contents identified were agonal or post-mortem events, supporting the contention that aspiration has limited relevance to the mechanism of SIDS.

International Child Care Practices study: breastfeeding and pacifier use

Although the Baby-Friendly Hospital Initiative advises that no pacifiers be given to breastfeeding infants, both breastfeeding and pacifier use may protect against sudden infant death syndrome. The International Child Care Practice Study data set on child care practices associated with sudden infant death syndrome risk from 21 centers in 17 countries was used to describe infant-feeding practices and pacifier use and assess factors associated with breastfeeding. At approximately 3 months of age, rates of breastfeeding only (4%-80%) and pacifier use(12.5%-71%) varied between centers. Pacifier use was negatively associated with breastfeeding, and a dose-response effect was noted. Other negative (multiple birth, smoking by mother) and positive (intention to breastfeed, bed sharing, mothers' education) associations with breastfeeding only were identified. Although causality should not be inferred, these associations are consistent with previous studies. Advice on pacifiers should include potential benefits as well as risks.

Pulmonary interstitial hemosiderin in infancy: a common consequence of normal labor

Deposits of hemosiderin are found frequently in the interstitium of the lungs of infants who die suddenly and have been a suggested marker for hypoxia during previous episodes of apnea. We studied the epidemiology of pulmonary interstitial hemosiderin (PIH) in 94 infants with a diagnosis of the sudden infant death syndrome that was established during the New Zealand Cot Death Study. Twenty-seven infants (29%) had widely distributed PIH. Associations were sought between PIH and variables on which information had been obtained from parental interviews or from medical records. Previous suggestions of associations with increasing birth weight and decreasing age at death were confirmed in multivariate analysis (P = 0.0018 and P = 0.03, respectively) and with increasing gestation in univariate analysis (P < 0.0001). PIH was not found in any of the 13 infants delivered by elective cesarean section compared with a 33% incidence in those exposed to labor (P = 0.02). There was no association with previous apnea. We consider that the likely explanation of these findings is that PIH is a residue of interstitial hemorrhage caused by chest compression during labor that occurs particularly in larger infants of greater gestational age and then clears gradually during early infancy.

Modifiable risk factors for SIDS in Germany: results of GeSID

BACKGROUND

The incidence of sudden infant death syndrome (SIDS) has been falling in Germany over the last decade. However, little is known about the prevalence and the importance of well-known risk factors in Germany since a local prevention campaign in 1992.

DESIGN

A 3-y, population-based, case-control study was conducted in half of Germany, consisting of 333 cases. All sudden and unexpected deaths in infancy, if they fitted the inclusion criteria, were included in the study. Parental interview was carried out soon after the death, and three living control infants, matched for age, gender, region and sleep time, were recruited.

RESULTS

The prevalence of placing infants prone to sleep was only 4% in the control group, but this was associated with a markedly increased risk of SIDS (adjusted odds ration, aOR=6.08). Other modifiable risk factors for SIDS were: maternal smoking during pregnancy, breastfeeding for less than 2 wk (aOR=1.71) and co-sleeping (aOR=2.71), while using a pacifier during the last sleep reduced the risk (aOR=0.39).

CONCLUSIONS

Previously recognized risk factors for SIDS also occur in Germany. Despite knowledge about the major modifiable risk factors for SIDS, these factors are still present in Germany. To reduce the incidence of SIDS in Germany, a continued effort is needed to inform all parents about preventable risk factors for SIDS.

Breastfeeding and the use of human milk

Considerable advances have occurred in recent years in the scientific knowledge of the benefits of breastfeeding, the mechanisms underlying these benefits, and in the clinical management of breastfeeding. This policy statement on breastfeeding replaces the 1997 policy statement of the American Academy of Pediatrics and reflects this newer knowledge and the supporting publications. The benefits of breastfeeding for the infant, the mother, and the community are summarized, and recommendations to guide the pediatrician and other health care professionals in assisting mothers in the initiation and maintenance of breastfeeding for healthy term infants and high-risk infants are presented. The policy statement delineates various ways in which pediatricians can promote, protect, and support breastfeeding not only in their individual practices but also in the hospital, medical school, community, and nation.

The prevalence and characteristics associated with parent-infant bed-sharing in England

AIMS

To investigate the characteristics of parent-infant bed-sharing prevalence in England.

METHODS

Data on night-time sleeping practices from a two year, local, longitudinal study and a three-year, national, cross-sectional study were obtained. A total of 261 infants in North Tees were followed up at 1 and 3 months of age, as were 1095 infants aged 1 week to 1 year from five English health regions.

RESULTS

Data from both studies found that almost half of all neonates bed-shared at some time with their parents (local = 47%, 95% CI 41 to 54; national = 46%, 95% CI 34 to 58), and on any one night in the first month over a quarter of parents slept with their baby (local = 27%, 95% CI 22 to 33; national = 30%, 95% CI 20 to 42). Bed-sharing was not related to younger mothers, single mothers, or larger families, and was not more common in the colder months, at weekends, or among the more socially deprived families; in fact bed-sharing was more common among the least deprived in the first months of life. Breast feeding was strongly associated with bed-sharing, both at birth and at 3 months. Bed-sharing prevalence was uniform with infant age from 3 to 12 months; on any one night over a fifth of parents (national = 21%, 95% CI 18 to 24) slept with their infants.

CONCLUSION

Bed-sharing is a relatively common practice in England, not specific to class, but strongly related to breast feeding.

Implementation of the SIDS guidelines in midwifery practice

The literature suggests that midwives strongly influence parenting practices immediately after birth and during early postnatal management of the newborn. Midwives must therefore be aware of the current evidence and public health recommendations for reducing the risk of Sudden Infant Death Syndrome (SIDS) and provide consistent information about use of the supine position. Midwives must also include information about environmental factors that are also known to increase the risk of SIDS such as exposure to cigarette smoke, covering the infant's face during sleep and other potential unsafe sleeping practices such as co-sleeping and bed sharing with their infant. The position midwives use to settle infants and place them for sleep is an important example for parents. The position favoured by midwives when placing a newborn to sleep will have a significant impact on parental practice after discharge home. A standardised evidenced based approach to the SIDS Guidelines immediately after birth will facilitate consistency in practice and uniformity in the message parents are given about safe sleeping practices for their newborn infant.

Breastfeeding and the risk of postneonatal death in the United States

OBJECTIVE

Breastfed infants in the United States have lower rates of morbidity, especially from infectious disease, but there are few contemporary studies in the developed world of the effect of breastfeeding on postneonatal mortality. We evaluated the effect of breastfeeding on postneonatal mortality in United States using 1988 National Maternal and Infant Health Survey (NMIHS) data.

METHODS

Nationally representative samples of 1204 infants who died between 28 days and 1 year from causes other than congenital anomaly or malignant tumor (cases of postneonatal death) and 7740 children who were still alive at 1 year (controls) were included. We calculated overall and cause-specific odds ratios for ever/never breastfeeding among all children, conducted race and birth weight-specific analyses, and looked for duration-response effects.

RESULTS

Overall, children who were ever breastfed had 0.79 (95% confidence interval [CI]: 0.67-0.93) times the risk of never breastfed children for dying in the postneonatal period. Longer breastfeeding was associated with lower risk. Odds ratios by cause of death varied from 0.59 (95% CI: 0.38-0.94) for injuries to 0.84 (95% CI: 0.67-1.05) for sudden infant death syndrome.

CONCLUSIONS

Breastfeeding is associated with a reduction in risk for postneonatal death. This large data set allowed robust estimates and control of confounding, but the effects of breast milk and breastfeeding cannot be separated completely from other characteristics of the mother and child. Assuming causality, however, promoting breastfeeding has the potential to save or delay approximately 720 postneonatal deaths in the United States each year.

Sudden unexplained infant death in 20 regions in Europe: case control study

BACKGROUND

After striking changes in rates of sudden unexplained infant death (SIDS) around 1990, four large case-control studies were set up to re-examine the epidemiology of this syndrome. The European Concerted Action on SIDS (ECAS) investigation was planned to bring together data from these and new studies to give an overview of risk factors for the syndrome in Europe.

METHODS

We undertook case-control studies in 20 regions. Data for more than 60 variables were extracted from anonymised records of 745 SIDS cases and 2411 live controls. Logistic regression was used to calculate odds ratios (ORs) for every factor in isolation, and to construct multivariate models.

FINDINGS

Principal risk factors were largely independent. Multivariately significant ORs showed little evidence of intercentre heterogeneity apart from four outliers, which were eliminated. Highly significant risks were associated with prone sleeping (OR 13.1 [95% CI 8.51-20.2]) and with turning from the side to the prone position (45.4 [23.4-87.9]). About 48% of cases were attributable to sleeping in the side or prone position. If the mother smoked, significant risks were associated with bed-sharing, especially during the first weeks of life (at 2 weeks 27.0 [13.3-54.9]). This OR was partly attributable to mother's consumption of alcohol. Mother's alcohol consumption was significant only when baby bed-shared all night (OR increased by 1.66 [1.16-2.38] per drink). For mothers who did not smoke during pregnancy, OR for bed-sharing was very small (at 2 weeks 2.4 [1.2-4.6]) and only significant during the first 8 weeks of life. About 16% of cases were attributable to bed-sharing and roughly 36% to the baby sleeping in a separate room.

INTERPRETATION

Avoidable risk factors such as those associated with inappropriate infants' sleeping position, type of bedding used, and sleeping arrangements strongly suggest a basis for further substantial reductions in SIDS incidence rates.

Factors relating to the infant's last sleep environment in sudden infant death syndrome in the Republic of Ireland

AIM

To identify risk factors for sudden infant death syndrome (SIDS) in the sleeping environment of Irish infants.

METHODS

A five year population based case-control study with parental interviews conducted for each case and three controls matched for age, place of birth, and last sleep period. A total of 203 SIDS cases and 622 control infants born 1994-98 were studied.

RESULTS

In a multivariate analysis, co-sleeping significantly increased the risk of SIDS both as a usual practice (adjusted OR 4.31; 95% CI 1.07 to 17.37) and during the last sleep period (adjusted OR 16.47; 95% CI 3.73 to 72.75). The associated risk was dependent on maternal smoking (OR 21.84; 95% CI 2.27 to 209.89), and was not significant for infants who were > or =20 weeks of age (OR 2.63; 95% CI 0.49 to 70.10) or placed back in their own cot/bed to sleep (OR 1.07; 95% CI 0.21 to 5.41). The use of pillows, duvets, and bedding with tog value > or =10 were not significant risk factors when adjusted for the effects of confounding variables, including maternal smoking and social disadvantage. However, the prone sleeping position remains a significant SIDS risk factor, and among infants using soothers, the absence of soother use during the last sleep period also significantly increased the SIDS risk (OR 5.83; CI 2.37 to 14.36).

CONCLUSION

Co-sleeping should be avoided in infants who are <20 weeks of age, or whose mothers smoked during pregnancy. The prone position remains a factor in some SIDS deaths, and the relation between soother use and SIDS is a complex variable requiring further study.

Determinants of nonsynostotic plagiocephaly: a case-control study

OBJECTIVE

There has been a large increase in reported cases of nonsynostotic plagiocephaly in infants since the adoption of supine sleeping recommendations to prevent sudden infant death syndrome. The objective of this study was to identify and quantify the determinants of nonsynostotic plagiocephaly in infants.

METHODS

One hundred infants who received a diagnosis of having nonsynostotic plagiocephaly were recruited as case patients and compared with 94 control subjects who were selected from a citywide database of infants. The infants all were aged between 2 and 12 months. Information concerning sociodemographic variables, obstetric factors, infant factors, and infant care practices was obtained by parental interview.

RESULTS

Case patients were significantly more likely to be male (adjusted odds ratio [aOR]: 2.51; 95% confidence interval [CI]: 1.23-5.16), to be a firstborn (aOR: 2.94; 95% CI: 1.46-5.96), and to have been premature (aOR: 3.26; 95% CI: 1.02-10.47). In the first 6 weeks, they were more likely to have been sleeping in the supine position (aOR: 7.02; 95% CI: 2.98-16.53), not to have had the head position varied when put down to sleep (aOR: 7.11; 95% CI: 2.75-18.37), and to have had <5 minutes a day of tummy time (OR: 2.26; 95% CI: 1.03-5.00). Mothers of case patients were more likely to perceive their infants as less active (aOR: 3.23; 95% CI: 1.38-7.56), to have a developmental delay (aOR: 3.32; 95% CI: 1.01-10.85), and to have had a definite preferred head orientation at 6 weeks (aOR: 37.46; 95% CI: 8.44-166.32). Case mothers were more likely to have no or low educational qualifications (aOR: 5.61; 95% CI: 2.02-15.56), although they were more likely to have attended antenatal classes (aOR: 6.61; 95% CI: 1.59-27.47).

CONCLUSIONS

Early identification of a preferred head orientation, which may indicate the presence of neck muscle dysfunction, may help prevent the development or further development of nonsynostotic plagiocephaly in infants. Plagiocephaly might also be prevented by varying the head position when putting the very young infant down to sleep and by giving supervised tummy time when awake.

Respiratory responses to hypoxia/hypercapnia in small for gestational age infants influenced by maternal smoking

AIM

To determine any variation in the respiratory responses to hypoxia/hypercapnia of infants born small for gestational age (SGA) to smoking and to non-smoking mothers.

METHODS

A total of 70 average for gestational age (AGA) infants (>36 weeks gestation, >2500 g, >25th centile for gestational age, and no maternal smoking), and 47 SGA infants (<10th centile for gestational age) were studied at 1 and 3 months of age, in quiet and active sleep. Respiratory test gases were delivered through a Perspex hood to simulate face down rebreathing by slowly allowing the inspired air to be altered to a CO(2) maximum of 5% and O(2) minimum of 13.5%. The change in ventilation with inspired CO(2) was measured over 5-6 minutes of the test. The slope of a linear curve fit relating inspired CO(2) to the logarithm of ventilation was taken as a quantitative measure of ventilatory asphyxial sensitivity (VAS).

RESULTS

There was no significant difference in VAS between the AGA and SGA infants (0.25 v 0.24). However within the SGA group, VAS was significantly higher (p = 0.048) in the infants whose mothers smoked during pregnancy (0.26 (0.01); n = 24) than in those that did not (0.23 (0.01); n = 23). The change in minute ventilation was significantly higher in the smokers than the non-smokers group (141% v 119%; p = 0.03) as the result of a significantly larger change in respiratory rate (8 v 4 breaths/min; p = 0.047) but not tidal volume.

CONCLUSIONS

Maternal smoking appears to be the key factor in enhancing infants' respiratory responses to hypoxia/hypercapnia, irrespective of gestational age.

Snoring in the first year of life

AIM

To describe the prevalence of snoring in infancy and the factors associated with snoring.

METHODS

The investigation comprised a cross-sectional study of 1800 infants. Snoring was ascertained by interviewer-administered questionnaire.

RESULTS

The prevalence of snoring was 15.8% in the first 4 wk of life and 26.1% in the past 2 wk. Snoring in the past 2 wk was associated with increasing age of the infant, male gender, maternal smoking, sleep position, number of respiratory infections and snoring in the first 4 wk of life after adjustment for potential confounders. No associations were found with snoring in the first 4 wk of life.

CONCLUSION

Snoring is common in infancy. The identified risk factors for snoring are probably causally related to snoring. Further studies are needed to establish whether snoring in infancy is associated with current or subsequent morbidity.

Airway alveolar attachment points and exposure to cigarette smoke in utero

The harmful effects of in utero cigarette smoke exposure include increased asthma symptoms and reduced lung function during the neonatal period, increased airway responsiveness to inhaled stimuli, and an increased risk of sudden infant death syndrome. Altered lung function may result from altered airway/lung structure. Airway dimensions, alveolar attachment points, and parenchymal elastin content were measured in 32 infants who died from sudden infant death syndrome and were grouped according to their perinatal cigarette smoke exposure. Compared with those without any exposure to cigarette smoke, the distance between alveolar attachments on airways was greater (p < 0.001) in infants exposed to cigarette smoke only in utero or both in utero and during the postnatal period but not different in those with only postnatal exposure. The percentage of elastin within the alveolar walls was similar in all the exposure groups. These findings suggest that in utero cigarette smoke exposure may result in abnormal airway function due to a reduction of the forces opposing airway narrowing.

Arousal responses and risk factors for sudden infant death syndrome

BACKGROUND

Failure to arouse from sleep has been postulated as a mechanism to explain the final pathway of sudden infant death syndrome (SIDS).

METHODS

We have reviewed the effects of the major risk factors for SIDS, prone sleep position, maternal smoking, prematurity and recent infection on arousability from sleep. In human infants it has been consistently demonstrated that arousal from sleep in response to a variety of stimuli is more difficult to induce from quiet sleep (QS) compared to active sleep (AS) over the first 6 months of life.

RESULTS

In the prone position both stimulus-induced and spontaneous arousability from both QS and AS were impaired at 2-3 weeks and 2-3 months, but not at 5-6 months of age in both term and preterm infants. In term infants exposed to maternal smoking during pregnancy both stimulus-induced and spontaneous arousability were impaired when infants slept supine in QS at 2-3 months of age. Healthy preterm infants showed no impairment in arousability compared with term infants at matched postconceptional ages. However, preterm infants with a history of apnoea and bradycardia of prematurity showed decreased arousal responses in both QS and AS and this impairment was positively correlated to their 'perinatal risk score'. Infants who had recently suffered an infection requiring hospitalization showed decreased arousability in QS on the day of discharge when compared to 2 weeks later when they were completely well.

CONCLUSIONS

In summary it has been found that the major risk factors for SIDS identified from epidemiological studies also decrease arousability from sleep in infants. We propose that this decreased arousability from sleep may be involved in the final pathway of SIDS.

The contribution of prone sleeping position to the racial disparity in sudden infant death syndrome: the Chicago Infant Mortality Study

BACKGROUND

Rates of sudden infant death syndrome (SIDS) are over twice as high among African Americans compared with Caucasians. Little is known, however, about the relationship between prone sleeping, other sleep environment factors, and the risk of SIDS in the United States and how differences in risk factors may account for disparities in mortality.

OBJECTIVE

To assess the contribution of prone sleeping position and other potential risk factors to SIDS risk in a primarily high-risk, urban African American population.

DESIGN, SETTING, AND POPULATION

Case-control study consisting of 260 infants ages birth to 1 year who died of SIDS between November 1993 and April 1996. The control group consists of an equal number of infants matched on race, age, and birth weight. Prospectively collected data from the death scene investigation and a follow-up home interview for case infants were compared with equivalent questions for living control participants to identify risk factors for SIDS.

MAIN OUTCOME MEASURES

Risk of SIDS related to prone sleeping position adjusting for potential confounding variables and other risk factors for SIDS, and comparisons by race-ethnicity.

RESULTS

Three quarters of the SIDS infants were African American. There was more than a twofold increased risk of SIDS associated with being placed prone for last sleep compared with the nonprone positions (odds ratio [OR]: 2.4; 95% confidence interval [CI]: 1.6-3.7). This OR increased after adjusting for potential confounding variables and other sleep environment factors (OR: 4.0; 95% CI: 1.8-8.8). Differences were found for African Americans compared with others (OR: 1.8; 95% CI: 1.2-2.6 and OR: 10.3, 95% CI: 10.3 [3.2-33.8, respectively]). The population attributable risk was 31%. Fewer case mothers (46%) than control mothers (64%) reported being advised about sleep position in the hospital after delivery. Of those advised, a similar proportion of case mothers as control mothers were incorrectly told or recalled being told to use the prone position, but prone was recommended in a higher proportion of black mothers (cases and controls combined) compared with nonblack mothers.

CONCLUSIONS

Prone sleeping was found to be a significant risk factor for SIDS in this primarily African American urban sample, and approximately one third of the SIDS deaths could be attributed to this factor. Greater and more effective educational outreach must be extended to African American families and the health personnel serving them to reduce prone prevalence during sleep, which appears, in part, to contribute to the higher rates of SIDS among African American infants.

Are risk factors for sudden infant death syndrome different at night?

AIMS

To determine whether the risk factors for SIDS occurring at night were different from those occurring during the day.

METHODS

Large, nationwide case-control study, with data for 369 cases and 1558 controls in New Zealand.

RESULTS

Two thirds of SIDS deaths occurred at night (between 10 pm and 7 30 am). The odds ratio (95% CI) for prone sleep position was 3.86 (2.67 to 5.59) for deaths occurring at night and 7.25 (4.52 to 11.63) for deaths occurring during the day; the difference was significant. The odds ratio for maternal smoking for deaths occurring at night was 2.28 (1.52 to 3.42) and that for the day 1.27 (0.79 to 2.03); that for the mother being single was 2.69 (1.29 to 3.99) for a night time death and 1.25 (0.76 to 2.04) for a daytime death. Both interactions were significant. The interactions between time of death and bed sharing, not sleeping in a cot or bassinet, Maori ethnicity, late timing of antenatal care, binge drinking, cannabis use, and illness in the baby were also significant, or almost so. All were more strongly associated with SIDS occurring at night.

CONCLUSIONS

Prone sleep position was more strongly associated with SIDS occurring during the day, whereas night time deaths were more strongly associated with maternal smoking and measures of social deprivation.

Triadic bed-sharing and infant temperature

The effects on infants of sleeping with their parents is currently the subject of much debate. One concern regarding infants who sleep in their parents' bed involves the possibility of overheating. Previous research reported a significantly greater core temperature of 0.1 degrees C among a cohort of bed-sharing infants compared with a matched cohort of infants sleeping alone. This paper presents a preliminary analysis of the overnight rectal temperature of 12 of the 20 infants who were monitored sleeping alone and with their parents on separate nights at the University of Durham Parent-Infant Sleep Lab. No significant differences were found in all night rectal temperature, or temperature from 2 h after sleep onset between bed-sharing and cot sleeping nights. These preliminary analyses suggest a night-time difference in rectal temperature between routine bed-sharers and routine cot sleepers, however, these findings will be further explored in the full analyses for this study.

Epidemiological investigation of sudden infant death syndrome infants--recommendations for future studies

In recent years the study of infant care practices within the sleeping environment has proved to be the single most important set of observations for reducing the risk of Sudden Infant Death Syndrome (SIDS). To further reduce the number of deaths and resolve the debate on safe infant care practice, a closer scrutiny of this environment is required. However, anecdotal observation from uncontrolled death-scene investigations and a reluctance to diagnose SIDS because of adverse social conditions or circumstantial evidence at the time of death is undermining future research. To investigate SIDS now means investigating the wider umbrella of all Sudden Unexpected Deaths in Infancy (SUDI) because of the potential for misdiagnosis. In trying to find out why SIDS infants die we have increasingly been forced to search for why infants survive in the first few months of life and it is this comparative component of epidemiological observation that has saved so many lives. A death-scene investigation is vital to any planned future investigation of SIDS but equally essential is a sleep-scene investigation of surviving infants to put any findings into context. SIDS infants are no longer scattered across the social strata and the cot is not the only environment in which they are found, social deprivation and use of the parental bed are now more discernable. Future studies should therefore reflect these changes with a second control group of surviving infants more closely matched to the type of environment in which SIDS infants might be found.

Assessment of infant physiology and neuronal development using magnetic resonance imaging

Previous work has demonstrated both that there are substantial individual differences in the rate of physiological development,and that infants with risk factors for Sudden Infant Death Syndrome (SIDS) develop more slowly, suggesting that their increased vulnerability may be due to delayed neuronal development associated with compromised development in fetal or early neonatal life. This project aims to test the hypothesis that individual differences in the rate of physiological development of infants correlate with measurable differences in the rate of brain development as assessed by magnetic resonance imaging (MRI). Sixty infants were recruited to this study in three different groups that are known to have differing rates of physiological development. MRI was performed successfully in 49 cases at 6 weeks of age without sedation. Forty-one of these cases had full follow-up (15 normal; 19 IUGR; 11 'high risk'). Postnatal physiological development was assessed by measuring age-related deep body temperature patterns during sleep. Neuronal development was assessed by subjective analysis of MRI images and objective measurements relating to myelination using T1 and diffusion weighted (23 cases) MRI images. As expected the normal group acquired the adult temperature pattern earlier, but this was not statistically significant. All MRI scan appearances were within normal limits. Ranking cases subjectively in order of maturity revealed no significant pattern. The normal group had a significantly higher myelination score than the IUGR and 'high risk' groups (P = 0.001). This trend was also shown by the diffusion weighted myelination score but did not reach statistical significance. No significant differences were seen in both the subjective and objective MRI measurements and development of nocturnal temperature patterns. The results suggest there may be differences in neurodevelopment between the different groups at 6 weeks of age but these are not linked to late development of temperature patterns. It is therefore unlikely that this related to a global delay in maturation.

Prone versus supine sleep position: a review of the physiological studies in SIDS research

A number of physiological studies, published over the last 10 years, have investigated the links between prone sleeping and sudden infant death syndrome (SIDS). This review evaluates those studies and derives an overview of the different affects of sleeping prone or supine in infancy. Generally, compared with the supine, the prone position raises arousal and wakening thresholds, promotes sleep and reduces autonomic activity through decreased parasympathetic activity, decreased sympathetic activity or an imbalance between the two systems. In addition, resting ventilation and ventilatory drive is improved in preterm infants, but in older infants (>1 month), there is no improvement in ventilation, and in 3-month-old infants, the position is adverse in terms of poorer ventilatory drive (in active sleep only). The majority of findings suggest a reduction in physiological control related to respiratory, cardiovascular and autonomic control mechanisms, including arousal during sleep in the prone position. Since the majority of these findings are from studies of healthy infants, continued reinforcement of the supine sleep recommendations for all infants is emphasized.

A longitudinal study of breastfeeding and weaning practices during the first year of life in Dunedin, New Zealand

OBJECTIVE

To investigate infant feeding practices during the first year of life in a group of white infants in Dunedin, New Zealand.

DESIGN

Prospective study of infants from birth to 12 months of age.

PARTICIPANTS

A self-selected sample of 74 white mothers and their infants born in Dunedin, New Zealand, between October 1995 and May 1996. Statistical analyses Regression analyses were performed to determine factors associated with successful breastfeeding initiation and duration.

RESULTS

Among mothers, 88% (n=65) initiated breastfeeding, 42% (n=31) were exclusively breastfeeding at 3 months, and 34% (n=25) were partially breastfeeding at 12 months. Intention to breastfeed increased the likelihood of successful breastfeeding initiation. Mothers who reported that they did not have enough breastmilk tended to exclusively breastfeed for a shorter period of time. Tertiary education and exclusively breastfeeding at 1 month were associated with a longer duration of breastfeeding. Perception of breastfeeding in public as embarrassing was associated with a shorter duration of breastfeeding. Among infants, 45% (n=33) were given nonmilk foods before 4 months of age, and 69% (n=51) were given unmodified cow's milk as a beverage before 12 months.

APPLICATIONS

Breastfeeding rates in this study, although higher than in many Western countries, were still lower than current recommendations. Our findings suggest that women should be taught how to increase their breastmilk supply. Parents should also be informed of the importance of delaying the introduction of nonmilk foods until their infant is 4 to 6 months of age and cow's milk until they are 12 months of age. Society also needs to address the social issue of embarrassment many mothers feel when breastfeeding in public.

Arousal from sleep in infants is impaired following an infection

Numerous studies have postulated a link between recent infection and Sudden Infant Death Syndrome (SIDS). In this study we contrasted arousal responses from sleep in infants on the day of discharge from hospital following an infection with those when fully recovered and also with well age-matched control infants. Thirteen term infants comprised the infection group and nine well infants acted as age-matched controls. All infants were studied using daytime polysomnography and multiple measurements of arousal threshold (cm H(2)O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep (AS) and quiet sleep (QS). All infants were studied on two occasions: firstly, immediately before discharge from the Paediatric ward, and secondly, 10-15 days later when they were completely well in the case of the infection group.Arousal thresholds in QS in the infection group were significantly elevated on the day of discharge (262 +/- 48 cm H(2)O) compared with 10-15 days later (205 +/- 31 cm H(2)O, p<0.05). Thresholds in the control group were not different between studies. This study provides evidence that arousability from QS is impaired following an infection and we postulate that this may explain the increased risk for SIDS following infection observed in previous studies.

A review of the anatomy of the upper airway in early infancy and its possible relevance to SIDS

BACKGROUND

Since the danger of prone sleeping in the first 6 months of life has been publicised, there has been a dramatic and consistent reduction in the incidence of sudden infant death syndrome (SIDS). However, unexpected infant deaths and apparent life-threatening events (ALTEs) continue to occur that are clearly not associated with known epidemiological risk factors.

AIMS

To review the unique features of the anatomy and function of the upper airway of the young infant which contribute to increased vulnerability to hypoxia in this age group. We discuss the clinical identification of those infants at risk of obstruction or restriction of the upper airway and the management of the 'at risk' infant.

CONCLUSIONS

In the era after the "back to sleep" campaigns, it is likely that an increasing proportion of cases of ALTEs and SIDS will be related to obstruction or limitation of upper airway size leading to sleep hypoxia/asphyxia. This type of problem may be anticipated by evaluation and investigation of infants with signs or a clinical history consistent with possible upper respiratory tract compromise, including micrognathia.

Interaction between bed sharing and other sleep environments during the first six months of life

This investigation was carried out to determine the relationship between bed sharing and other places of infant sleep in the first six months of life, and to identify patterns of change in the place of infant sleep for infants who do and do not routinely bed share in the first six months of life. The sleep--wake behaviour and place of infant sleep were recorded, at weekly intervals, for bed sharing (n=25) and non-bed sharing (n=68) infants between 2 and 24 weeks after birth. Bed sharing infants spent a significantly increased proportion of their total sleep time per 24 h in other sleep environments which favoured close parental proximity and significantly less time in solitary sleep. Non-bed sharing infants spent a substantial proportion of their time sleeping alone from 2 weeks of age whereas the transition to sleeping alone occurred after 16 weeks for bed sharing infants. We have found that bed sharing acts as a proxy for increased close parental proximity during the first six months of life. This may be of significance in studies which examine the relationship between bed sharing and sudden infant death syndrome.

Infant care practices in New Zealand: a cross-cultural qualitative study

This paper describes and compares the infant care practices and beliefs of Maori, Tongan, Samoan, Cook Islands, Niuean and Pakeha (European) caregivers residing in Auckland, New Zealand. Focusing on four areas--sources of support and advice; infant feeding; infant sleeping arrangements; and traditional practices and beliefs--it explores inter-ethnic similarities and differences and intra-ethnic tensions. The international literature indicates that there can be significant cultural variation in infant care practices and in the meanings attributed to them. There is, however, little New Zealand literature on this topic, despite its importance for effective health service and health message delivery. Participants were primary caregivers of infants under 12 months. An average of six focus groups were conducted within each ethnic group, resulting in a total of 37 groups comprising 150 participants. We found similarities across all ethnic groups in the perceived importance of breastfeeding and the difficulties experienced in establishing and maintaining this practice. The spectrum of behaviours ranged widely with differences most pronounced between Pacific caregivers, especially those Island-raised, and Pakeha caregivers, especially those in nuclear families. Amongst the former, norms included: the family as central in providing support and advice; infant bedsharing; abdominal rubbing during pregnancy; baby massage; and the importance of adhering to traditional protocols to ensure infant well-being. Amongst the latter, norms included: strong reliance on professional advice; looser family support networks; the infant sleeping in a cot; and adherence to Western biomedical understandings of health and illness. Maori caregivers bridged the spectrum created by these groups and exhibited a diverse range of practices. Intra-cultural differences were present in all groups indicating the dynamic nature of cultural practices. They were most evident between Pacific-raised and New Zealand-raised Pacific caregivers, with the latter attempting to marry traditional with Western beliefs and practices.

Nasal and intrapulmonary haemorrhage in sudden infant death syndrome

BACKGROUND

Fresh intrapulmonary and oronasal haemorrhages in cases of sudden infant death syndrome (SIDS) might be markers for accidental or intentional smothering inappropriately diagnosed as SIDS.

AIM

To compare the incidence, epidemiological association, and inter-relation of nasal haemorrhage, intrapulmonary haemorrhage, and intrathoracic petechiae in infant deaths certified as SIDS.

METHODS

In SIDS cases from a large nationwide case-control study, a wide range of variables were compared in cases with and without reported nasal haemorrhage and, in a subgroup of cases, in those with and without pathologically significant intrapulmonary haemorrhage.

RESULTS

Nasal haemorrhage was reported in 60 of 385 cases (15%) whose parents were interviewed. Pathologically significant intra-alveolar pulmonary haemorrhage was found in 47% of 115 cases studied, but was severe in only 7%. Infants with nasal haemorrhage had more haemorrhage into alveoli and air passages than age matched cases without nasal haemorrhage. In multivariate analysis, nasal haemorrhage was associated with younger infant age, bed sharing, and the infant being placed non-prone to sleep. Intrapulmonary haemorrhage was associated with the same three factors in univariate analysis, but in multivariate analysis only younger infant age remained statistically significant. There was no significant association between nasal or intra-alveolar haemorrhages and intrathoracic petechiae.

CONCLUSIONS

Nasal and intrapulmonary haemorrhages have common associations not shared with intrathoracic petechiae. Smothering is a possible common factor, although is unlikely to be the cause in most cases presenting as SIDS.

Medicalization and women's knowledge: the construction of understandings of infant feeding experiences in post-WW II New Zealand

For most of the twentieth century infant feeding knowledge has been constructed by medical scientists and health professionals. However, for a short time around the 1970s, New Zealand women (re)claimed the power to author their own knowledge based upon experience. This coincided with a dramatic return to breastfeeding on a national scale. Using New Zealand women's narratives of their infant feeding experiences over the past 50 years, this article brings to the foreground the importance of women's subjective construction of knowledge, their positioning within it, and the suppression of rudimentary discourses when that power is removed or relinquished in the process of remedicalization.

Review of risk factors for sudden infant death syndrome

Sudden infant death syndrome (SIDS) accounts for the largest number of deaths during the first year of life in developed countries. The possible causes of SIDS are numerous and, to date, there is no adequate unifying pathological explanation for SIDS. Epidemiological studies have played a key role in identifying risk factors, knowledge of which has underpinned successful preventive programmes. This review critically assesses information on the main risk factors and causal hypotheses put forward for SIDS, focusing on research published since 1994. The overall picture that emerges from this review is that affected infants are not completely normal in development, but possess some inherent weakness, which may only become obvious when the infant is subjected to stress. Initially there may be some minor impairment or delay in development of respiratory, cardiovascular or neuromuscular function. None of these is likely to be sufficient, in isolation, to cause death and, provided the infant survives the first year of life, may no longer be of any significance. However, when a compromised infant is confronted with one or more stressful situations, several of which are now clearly identified as risk factors, and from which the majority of infants would normally escape, the combination may prove fatal.

Why some women do not breast feed: bottle feeding and fathers' role

OBJECTIVE

To explore women's experiences and perceptions of baby feeding and to explore the explanations offered by women who choose to either breast or bottle feed.

DESIGN

A qualitative study, which was prospective in design. Participants were interviewed three times: the first stage was between six and 14 weeks of pregnancy; the second stage was between 34 and 39 weeks; and the third stage was between six and 14 weeks after childbirth.

PARTICIPANTS

19 participants were recruited to the study group via 12 antenatal clinics in Coventry, UK.

FINDINGS AND DISCUSSION

The data indicate that participants make baby-feeding decisions either prior to conception or early in the pregnancy. Findings also indicate that both breast and bottle feeders possessed knowledge of the benefits of breast feeding, but this did not seem to influence decision making. One of the most significant factors influencing the decision to bottle feed appears to be a desire for paternal involvement.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

To increase the incidence of breast feeding, health-care professionals should consider the need for preconceptual health promotion. The role of paternal involvement in baby-feeding decisions also needs to be acknowledged and men need to be included in breast-feeding promotion campaigns.

Changing trends in the diagnosis of sudden infant death

A study of 114 consecutive cases of unexpected infant death that occurred in South Australia over a 5-year period from January 1994 to December 1998 was undertaken. There were 45 deaths attributed to sudden infant death syndrome (SIDS), 19 to natural causes, 21 to accidents. and 5 to homicides; 24 cases were listed as "undetermined." Although there has been a genuine and continued decline in SIDS numbers in this population, there has also been an increase in the diagnosis of cases of accidental asphyxia due to unsafe sleeping environments and of cases in which the family background and autopsy findings suggested more complex mechanisms. The change in diagnostic profile has followed the introduction of more rigorous clinical history review, death scene examination, and autopsy testing. Thus, although diagnostic outcomes have altered in this population, it is more likely the result of more careful interpretation of the extensive investigations that are now undertaken rather than arbitrary reclassification.

[Mothers' behavior regarding infant sleep position: effects of the last public campaign to prevent sudden infant death syndrome]

BACKGROUND

To define infant care practices in maternity units and those subsequently adopted at home. Using these data, we evaluated the acceptance and application of recommendations issued by the previous public education campaign on infant sleeping position as related to sudden infant death syndrome.

PATIENTS AND METHODS

A survey was carried out in two maternity units (Port-Royal and Créteil) and in one pediatric consultation unit (affiliated with Port-Royal maternity).

RESULTS

The mixed position (side or back) is used equally with, respectively, 47% at Port-Royal and 45% at Créteil. The supine sleeping position (French public health recommendations) is used by 12% of the mothers at Port-Royal and by 40% at Créteil. It appears that hospital nurseries play an important role in determining the mother's preference for the sleeping position (64% at Port-Royal and 54% at Créteil), but it does not adequately explain all mothers' responses. However, as the infants mature (> two months old), the more spontaneously they changed their sleeping position. All the infants placed in a side sleeping position moved to a supine sleeping position during the night. Upon awakening, infants were found mostly in the supine position (in contrast to the national public education campaign).

CONCLUSION

Our results show that mothers and hospital nurseries were distressed in terms of ensuring the supine sleeping position of the infant. New choices of sleeping positions were initiated by mothers. For example, they used the side position after feedings essentially in the case of reflux or during the daytime. The supine position was used when the mothers were assured that any problems had been avoided or only during the night.

Ventilatory sensitivity to mild asphyxia: prone versus supine sleep position

AIMS

To compare the effects of prone and supine sleep position on the main physiological responses to mild asphyxia: increase in ventilation and arousal.

METHODS

Ventilatory and arousal responses to mild asphyxia (hypercapnia/hypoxia) were measured in 53 healthy infants at newborn and 3 months of age, during quiet sleep (QS) and active sleep (AS), and in supine and prone sleep positions. The asphyxial test mimicked face down rebreathing by slowly altering the inspired air: CO(2), maximum 5% and O(2), minimum 13.5%. The change in ventilation with inspired CO(2) was measured over 5-6 minutes of the test. The slope of a linear curve fit relating inspired CO(2) to the logarithm of ventilation was taken as a quantitative measure of ventilatory asphyxial sensitivity (VAS). Sleep state and arousal were determined by behavioural criteria.

RESULTS

At 3 months of age, prone positioning in AS lowered VAS (0.184 prone v 0.269 supine, p = 0.050). At newborn age, sleep position had no effect on VAS. Infants aged 3 months were twice as likely to arouse to the test than newborns (p = 0.013). Placing infants prone as opposed to supine increased the chances of arousal 1.57-fold (p = 0.035).

CONCLUSION

Our findings show 3 month old babies sleeping prone compared to supine have poorer ventilatory responses to mild asphyxia, particularly in AS, but the increased prevalence of arousal is a protective factor.

CLINICAL REVIEW ARTICLE: Is changing the sleep environment enough? Current recommendations for SIDS

Sudden infant death syndrome (SIDS or cot death) was the major cause of post-neonatal infant death in many countries in the late 1970s and 1980s. There is now very strong evidence that public intervention campaigns targeting the prone sleeping position, which had been identified by epidemiological studies as a major risk factor, were followed by substantial falls in the rate of SIDS. In the present review we discuss the evidence on which current recommendations for the prevention of SIDS are based. The prone sleeping position is now clearly causally associated with SIDS. Further reductions in SIDS may be produced by recommending the back sleeping position as opposed to the side position. Maternal smoking in pregnancy and bed sharing by infants of mothers who smoke are also strongly associated with SIDS, but have been harder to influence. Paternal smoking has also been implicated, although the magnitude of the reported risk is small. Finally, breastfeeding, pacifier use and having the infant sharing the parents bedroom, but not the bed, may also reduce risk. Continued reductions in SIDS mortality will require innovative public health education to target these major risk factors, while building on the "back to sleep" approach.