Preventing and postponing death: trends in Tennessee infant mortality.

Infants born in Tennessee between 1984 and 1988 experienced reduced mortality compared with those born in the 5 years previous. For all birthweight singleton infants, the reduction from 10.2 to 8.4 deaths per 1000 live births represents an 18% decline in mortality. The most impressive gain made was for very low birthweight (less than 1500 g) infants in the neonatal period, where mortality was reduced 24%. However, for these infants there was nearly a sixfold increase in the postneonatal mortality associated with prematurity-related causes.     

Epidemiology of neonatal necrotising enterocolitis: a population-based study

We examined the birthweight-, gender- and race-specific incidence as well as the biodemographic and clinical correlates of necrotising enterocolitis (NEC) in a well-defined six-county perinatal region in upstate New York. We conducted a retrospective, 8-year population-based survey to identify all cases of proven NEC (modified Bell stage II and above) in the area's regional neonatal intensive care unit (NICU). The denominator used to calculate the incidence was obtained from the Statewide Planning Research Cooperative System. Incidence was expressed as cases per 1000 live births. A total of 85 documented cases of proven NEC was identified in a six-county perinatal region that experienced 117 892 live births during the 8-year period. The average annual incidence was 0.72 cases per 1000 live births [95% CI 0.57, 0.87 per 1000 live births]. The highest incidence of NEC occurred among infants weighing 750-1000 g at birth and declined with increasing birthweight. The urban county had a 1.53 times higher risk of NEC than rural counties [95% CI 0.9, 2.6]. The overall incidence of NEC for non-Hispanic blacks was significantly greater than that for non- Hispanic whites (2.2 vs. 0.5 cases per 1000 live births, P = 0.00). The differences remained statistically significant even after correction for birthweight. Most cases (93%) in this series were preterm (gestational age <37 weeks). Only two patients were never fed before the diagnosis of NEC was confirmed. Positive blood cultures were documented in 27% of the cases with a predominance of Gram-negative enteric micro-organisms. NEC remains an important health problem especially for preterm infants and the non-Hispanic black population.     

Stillbirth and infant mortality in singletons by cause of death,birthweight, gestational age and birthweight‐for‐gestation,Newcastle upon Tyne 1961–2000

Glinianaia SV, Rankin J, Pearce MS, Parker L, Pless‐Mulloli T. Stillbirth and infant mortality in singletons by cause of death, birthweight, gestational age and birthweight‐for‐gestation, Newcastle upon Tyne 1961–2000. Paediatric and Perinatal Epidemiology 2010. The dramatic reduction observed in stillbirth and infant mortality over the last few decades has not been assessed by both birthweight and gestation. We have explored temporal changes in stillbirth and infant mortality in Newcastle upon Tyne, UK, by cause of death, birthweight, gestational age, birthweight standardised for gestation and infant sex during 1961–2000. We included 131 044 singleton births to mothers resident in Newcastle, including 1342 stillbirths and 1620 infant deaths. Cause‐, birthweight‐, gestational age‐ and birthweight‐for‐gestation‐specific stillbirth (per 1000 total births) and infant mortality (per 1000 livebirths) rates were compared between 1961–80 and 1981–2000 and between individual consecutive decades. Between 1961 and 2000, total stillbirth and infant mortality rates declined dramatically from 23.4 to 4.7 per 1000 total births and from 25.7 to 5.9 per 1000 livebirths, respectively. Rates fell continuously during the first two study decades; however, from 1981–90 to 1991–2000 the decline was not statistically significant. Between 1961–80 and 1981–2000, both stillbirth and infant mortality significantly declined in all birthweight and gestational age categories and for most leading causes of death. Although the population mean birthweight during 1981–2000 [3304 g (SD ± 569)] was significantly higher than during 1961–80 [3255 g (SD ± 572)] (P < 0.0001), the lowest stillbirth and infant mortality rates in 1981–2000 were consistently at about 1 SD above the mean birthweight, with mortality rates increasing for babies with lower or higher weight‐for‐gestation. Declines in stillbirth and infant mortality in Newcastle were associated with reductions in birthweight‐ and gestational age‐specific mortality rates and occurred in most cause‐specific groups of death.     

Trends in reporting of maternal drug abuse and infant mortality among drug-exposed infants in New York City

New York City trends in maternal drug abuse during pregnancy and in mortality rates for infants with in utero drug exposure are reported; causes of death among drug-exposed infants are studied, as is the association between maternal drug abuse and other factors that contribute to infant mortality (e.g., low birthweight, lack of prenatal care). Data for this study are derived from the linked files of New York City birth and infant death certificates. Reports of infants born to drug abusing mothers increased from 6.7 per 1000 live births in 1981 to 20.3 per 1000 live births in 1987, with abuse of cocaine accounting for most of the rise. When standardized for race and ethnicity, the mortality rate for drug-exposed infants born from 1978 through 1986 was 35.9, or 2.4 times that for infants in New York City in general. Drug-exposed infants were over three times as likely as infants in the general population to be of low birthweight. The association of both opiates and cocaine with increased mortality and low birthweight was similar. Death rates from SIDS and AIDS were especially higher for drug-exposed infants than for those in the general population, and were similar for opiate- and cocaine-exposed infants. The impact of drug abuse on infant mortality rates in selected low socioeconomic health districts is discussed.     

Cerebral palsy and multiple births in China

BACKGROUND: A population-based study on prevalence of cerebral palsy in multiple births has not been carried out in China. The purpose of this paper was to determine the prevalence of cerebral palsy in multiple births and to explore the influence of multiple pregnancy on cerebral palsy after controlling for birthweight. METHODS: A cross-sectional study of cerebral palsy was carried out among 388,192 children aged <7 years in seven cities of Jiangsu province in China. Information about birthweight and plurality was obtained from routine health care records. Pediatricians at city level diagnosed all cases. All the doctors involved had taken part in a training programme held by Beijing Medical University. Stratified analysis by birthweight and its standard normal deviate was employed to compare the prevalence of cerebral palsy in multiples and singletons. RESULTS: The prevalence of cerebral palsy for children aged <7 years in multiples was 9.7 per 1000 children (95% confidence interval [CI]: 6.5-14.0), which was 6.5 times that in singletons (95% CI: 4.4-9.3). The overall neonatal mortality rate was 60.9 per 1000 liveborn multiples, being highest (944.4 per 1000) in the 500-999 g birthweight groups. Most liveborn multiples weighing <1500 g at birth probably died from diseases related to very low birthweight prior to this study. The prevalence of cerebral palsy in multiple births was likely to be higher than that reported in developed countries for children weighing 1500-2499 g even though our data were from a cross-sectional study. When stratified by birthweight, the prevalence of cerebral palsy in multiples weighing <2500 g had tended to be lower than that of singletons in the same birthweight group. In contrast, in normal birthweight categories multiple births had a higher prevalence of cerebral palsy than singletons. When stratified by birthweight normal deviate, the prevalence of cerebral palsy in multiple births was uniformly higher than that in singletons in all birthweight strata and the prevalence of cerebral palsy among multiples appeared to be augmented as birthweight increased. CONCLUSION: The prevalence of cerebral palsy in multiples, 9.7 per 1000 children, is 6.5 times that in singletons. Survival of low birthweight infants is lower in China than in developed countries and survival quality of Chinese children weighing 1500-2499 g needs to be further improved. In terms of birthweight multiples and singletons may be heterogeneous. It might be difficult to directly use actual birthweight specific prevalence to compare the prevalence of cerebral palsy in multiples and singletons. Birthweight normal deviate specific prevalence of cerebral palsy suggests that multiple pregnancy is an independent risk factor for cerebral palsy in all birthweight groups. Multiples are in adverse circumstances very early in gestation and as the foetus matures the risk of cerebral palsy increases.     

Children with cerebral palsy: severity and trends over time

Increasingly, more very-low-birthweight infants in the developed world are now expected to survive the neonatal period than was previously the case. There are concerns that there may be a related increase in the number of infants developing severe sensorimotor impairments. Pooled data from five registers contributing to the UK Network of Cerebral Palsy Registers, Surveys and Databases were used to identify patterns of motor impairment in relation to additional impairments and to birthweight, and to assess whether prevalence of cerebral palsy (CP) by birthweight and by severity of motor impairment had changed over time. Low-birthweight infants are at greater risk of developing CP than larger-birthweight babies.
The CP rate amongst children with birthweights <2500 g was significantly higher at 16 per 1000 livebirths [95% confidence interval (CI) 14.9, 16.2] than 1.2 per 1000 livebirths [95% CI 11, 1.2] for normal-birthweight children. Despite being at greater risk of developing CP, smaller-birthweight babies are proportionately less likely to develop the most severe forms of motor impairment. Of those born weighing ≥2500 g, 23% compared with 15% weighing <1000 g ( P  < 0.001) were in the most severely motor impaired group. Severe motor impairment is associated with higher levels of additional impairments. CP rates for each motor impairment group in the 1990s were similar to those in the late 1970s. Rates of CP among infants born below normal birthweight are high but have decreased over time. The CP rate for infants weighing 1000–1499 g at birth decreased from around 180 per 1000 livebirths in 1979 to around 50 per 1000 livebirths from the early 1990s onwards.     

The epidemiological transition in maternal and child health in a Brazilian city, 1982-93: a comparison of two population-based cohorts

Two studies carried out in 1982 and 1993 in the city of Pelotas, Southern Brazil, provide a unique opportunity for assessing the impact on maternal and child health of the economic and health care changes, which took place in Brazil in this period. The cohorts of mothers and infants of 1982 and 1993 were studied from the time of delivery. In both years, all mothers identified in the city's maternity hospitals answered a standardised questionnaire and their infants were examined. Over 99% of all children born in the city in each of the 2 years were included in the cohorts. Deaths occurring among these children were monitored prospectively, as well as all hospital admissions in the 1993 cohort. In the 1982 study, attempts were made to locate a 25% sample of the children at the mean age of 12 months using the addresses collected at the hospital (82% of the children were located), and all of the cohort children at the mean age of 20 months and 42 months, through a city census (87% were located in both follow-ups). In the 1993 study, 20% of all children plus all low birthweight infants were sought at 12 months of age, using the addresses collected at the hospital, and 95% were successfully traced. There was a 12% fall in the number of births occurring in 1993 (5,304 births), in comparison with 1982 (6,011 births), in spite of the increase in the population of reproductive age in the city during the decade. There was a marked difference in maternal height and weight at the beginning of pregnancy, with women giving birth in 1993 being, on average, 3.4 cm taller and 2.5 kg heavier than those who gave birth in 1982. The proportion of preterm babies (<37 weeks), measured by the date of last menstrual period, increased from 5.6% in 1982 to 7.5% in 1993. The median duration of breast feeding increased from 3.1 months in 1982 to 4.0 months in 1993. At 12 months of age, the prevalence of deficit of weight for age decreased from 5.4% in 1982 to 3.7% in 1993. The prevalence of deficit of height for age, however, increased from 5.3% to 6.1%. The perinatal mortality rate dropped 31%, from 32.2 per 1,000 births in 1982 to 22.1 deaths per 1,000 births in 1993. There was also a marked reduction in the infant mortality rate, from 36.4 per 1,000 livebirths in 1982 to 21.1 per 1,000 livebirths in 1993. The findings of the study indicate that there were improvements in the decade for most of the indicators evaluated, with the exception of birthweight and gestational age. It appears that improvements in perinatal and infant mortality rates are largely due to improvements in the health care sector.     

Race and birthweight in biracial infants.

OBJECTIVES. The purpose of the study was to determine the role of infant race as a determinant of the Black-White disparity in low birthweight (< 2500 g). METHODS. Univariate analysis and multivariate logistic regression were performed on Illinois vital records from 1982 and 1983 and on 1980 United States census income data. RESULTS. Fourteen percent of the infants born to Black mothers and White fathers were of low birthweight, compared with 9% of infants born to White mothers and Black fathers and 6% of a random sample of White infants. Both groups of biracial infants were more likely to have been born to unmarried mothers and to reside in very low-income (< $10,000 per year) census tracts than were White infants. When all confounding variables were entered into a logistic model, the adjusted odds ratio of low birthweight for biracial infants born to Black mothers and White fathers equaled 1.4. When biracial infants born to White mothers and Black fathers were compared with White infants, the adjusted odds ratio of low birthweight equaled 1.0. CONCLUSIONS. Paternal and consequent infant race does not affect the birthweight distribution of those born to White mothers and Black fathers. Unidentified factors closely related to maternal race underlie the Black-White disparity in infant birthweight.     

The changing pattern of cerebral palsy in Avon

Summary. The overall rate of cerebral palsy excluding post-neonatal cases, has remained relatively constant, varying between 1.93 and 2.27 per 1000 births over the 20-year period between 1969 and 1988 in Avon. The rate of the subgroup of spastic cerebral palsy varied from 1.40 to 1.78 per 1000 births over the same time period.
In singletons the corresponding figures were 1.80-2.17 per 1000 births and 1.28-1.67 per 1000 births, and in multiple births the figures were 7.12-8.80 per 1000 births and 7.12-8.44 per 1000 births. Although the overall rates have remained fairly constant there was an increase in incidence in the later years among children with low birthweight and short gestation.     

Prevalence of cerebral palsy in China

BACKGROUND: A population-based study on the prevalence of cerebral palsy has not been previously carried out in China. The purpose of the present paper was to determine the overall and birthweight-specific prevalence of cerebral palsy. METHODS: A cross-sectional study of cerebral palsy was carried out among 388192 children aged <7 years in seven cities of Jiangsu province in China from May to July 1997. Information about birthweight was obtained from routine health care records. Doctors from township and city hospitals examined all eligible children and doctors at city level finally diagnosed all cases. All the doctors involved had taken part in a training programme held by Beijing Medical University in April 1997. RESULTS: The total prevalence of cerebral palsy was 1.6 per 1000 children and the birthweight-adjusted prevalence 2.8 per 1000 children (using Australia's neonatal survivors 1994 as a standard population). The overall neonatal mortality rate was 6.8 per 1000 live births, being highest (581.1 per 1000) in the 1000-1499 g birthweight group. The birthweight-specific cerebral palsy prevalence ranged from 0.8 per 1000 children in children weighing 3750-3999 g to 67.3 in children weighing 1500-1749 g. Children weighing 3500-3999 g at birth were at the lowest risk of cerebral palsy. In a given low birthweight group the prevalence of cerebral palsy in China was higher than that in developed countries even though this study was unable to include those who died at risk of, or with cerebral palsy. However, the prevalence of cerebral palsy at normal birthweight was almost the same as that in developed countries. In all, about 2% of all children were of low birthweight (<2500 g), with those weighing <1500 g accounting for about 0.02%. Children weighing <2500 g at birth contributed 24% of all cerebral palsy cases with 99% in the group 1500-2499 g. CONCLUSIONS: The prevalence of cerebral palsy for children aged <7 years is 1.6 per 1000 children. It is estimated that there are 310000 children with cerebral palsy in China and as the survival of low birthweight infants improves the prevalence of cerebral palsy will rise. Survival of low birthweight infants is lower in China than in developed countries and our findings suggest the survival quality of these Chinese children needs to be improved and that intrapartum and neonatal antecedents might play an important role in the aetiology of cerebral palsy compared to developed countries.     

Perinatal mortality and its relationship to the reporting of low-birthweight infants.

OBJECTIVES: This study examined changes in the reporting of very low-birthweight infants in Alabama from 1974 to 1994 and the impact on perinatal mortality rates. METHODS: Linked live birth, neonatal death, and stillbirth records of infants born weighing less than 1500 g were compared. RESULTS: The changes in mortality over time ranged from a drop from 100% to 92% in the under-500-g group to a drop from 39% to 4% in the 1000-to 1499-g group. The percentage of total births weighing less than 500 g increased by 155%; the percentage of 1000- to 1499-g births increased by only 7%. As a result, the percentage of neonatal mortality attributable to live births below 500 g increased from 3% to 32%. CONCLUSIONS: Increased reporting of births below 500 g has masked improvements in neonatal mortality.     

Perinatal mortality in southern Brazil: a population-based study of 7392 births

Perinatal, fetal and early neonatal mortality rates were determined in a population of 7392 babies born in hospitals in Pelotas (total population, 260 000) during 1982. These babies represented over 99% of all births in the city in that year. The perinatal mortality rate for singletons was 31.9 per 1000 total births, the fetal mortality rate being 16.2 and the early neonatal mortality rate 15.9 per 1000 total births.     

Analysis by gestational age of cerebral palsy in singleton births in north-east England 1970-94

We report from a well-established cerebral palsy (CP) register the changes in CP rates by gestational age for singleton births over a 25-year period in north-east England. The gestational ages of numerators and denominators are of high accuracy back to 1970 because academic units in paediatrics and obstetrics were studying the assessment of gestational age in individual infants, and the distribution of gestational age across all births in the north-east from the 1960s. The rate of CP rose between 1970-75 and 1990-94 from 1.6 to 2.3 per 1000 singleton neonatal survivors, a rise of 0.7/1000 [95% CI 0.2, 1.3]. There was little change in the rate of CP in term infants whereas in preterm infants (<37 weeks) it rose from 5.5 to 16.8, a rise of 11.3/1000 [95% CI 5.9, 16.8]. Rises occurred in the three preterm gestational age bands <28, 28-31, 32-36 weeks with the most marked rise in those <28 weeks from 0 to 112.7. The proportion of all cases of CP arising in the preterm group rose from 19% to 45%; and the proportion of the severest cases arising in the preterm group rose from 8% to 55%. In those born after 32 weeks, there is a preponderance of small-for-gestation infants, with 10% more than two standard deviations below the mean. All types of CP are more common in infants below average weight for gestation and this is most marked for the non-spastic types that are almost only seen in term, small-for-gestation infants. Gestational age is the crucial determinant of rate of CP and the increase in prevalence seen over the past 25 years is due to increased rates in preterm infants, not term infants. Both conclusions, suspected from birthweight analyses, are now demonstrated conclusively, with the contribution coming from those 32-36 weeks gestation as well as very preterm infants.     

Adverse perinatal and neonatal outcomes and their determinants in rural Vietnam 1999-2005

Population-based estimations of perinatal and neonatal outcomes are sparse in Vietnam. There are no previously published data on small for gestational age (SGA) infants. A rural population in northern Vietnam was investigated from 1999 to 2005 (n=5521). Based on the birthweight distributions within the population under study, reference curves for intrauterine growth for Vietnamese infants were constructed and the prevalence and distribution of SGA was calculated for each sex. Neonatal mortality was estimated as 11.6 per 1000 live births and the perinatal mortality as 25.0 per 1000 births during the study period. The mean birthweight was 3112 g and the prevalence of low birthweight was 5.0%. The overall prevalence of SGA was 6.4%. SGA increased with gestational age and was 2.2%, 4.5% and 27.1% for preterm, term and post-term infants, respectively. Risk factors for SGA were post-term birth: adjusted odds ratio (AOR) 7.75 [95% CI 6.02, 9.98], mothers in farming occupations AOR 1.72 [95% CI 1.21, 2.45] and female infant AOR 1.61 [95% CI 1.27, 2.03]. There was a pronounced decrease in neonatal mortality after 33 weeks of gestation. Suggested interventions are improved prenatal identification of SGA infants by ultrasound investigation for fetal growth among infants who do not follow their expected clinical growth curve at the antenatal clinic. Other suggestions include allocating a higher proportion of preterm deliveries to health facilities with surgical capacity and neonatal care.     

Explaining the 2001-02 infant mortality increase: data from the linked birth/infant death data set.

The U.S. infant mortality rate increased from 6.8 infant deaths per 1,000 live births in 2001 to 7.0 in 2002, the first increase in more than 40 years. From 2001 to 2002 infant mortality rates increased for very low birthweight infants as well as for preterm and very preterm infants. Although infant mortality rates for very low birthweight infants increased, most of the increase in the infant mortality rate from 2001 to 2002 was due to a change in the distribution of births by birthweight and, more specifically, to an increase in infants born weighing less than 750 grams (1 lb 10 1/2 oz). The majority of infants born weighing less than 750 grams die within the first year of life; thus, these births contribute disproportionately to the overall infant mortality rate. Increases in births at less than 750 grams occurred for non-Hispanic white, non-Hispanic black, and Hispanic women. Most of the increase occurred among mothers 20-34 years of age. Although multiple births contributed disproportionately, most of the increase in births at less than 750 grams occurred among singletons. Three hypotheses were evaluated to assess their possible impact on the increase in less than 750-gram births: first, possible changes in the reporting of births or fetal deaths; second, possible changes in the risk profile of births; and third, possible changes in medical management of pregnancy. Although each of these factors may have contributed to the increase, the relative effects of these and other factors remain unclear. More-detailed studies are needed to further explain the 2001-02 infant mortality increase.     

Explaining the 2001-2002 infant mortality increase in the United States: data from the linked birth/infant death data set.

The U.S. infant mortality rate (IMR) increased from 6.8 infant deaths per 1,000 live births in 2001 to 7.0 in 2002, the first increase in more than 40 years. From 2001 to 2002, IMR increased for very low birthweight infants as well as for preterm and very preterm infants. Although IMR for very low birthweight infants increased, most of the increase in IMR from 2001 to 2002 was due to a change in the distribution of births by birthweight and, more specifically, to an increase in infants born weighing less than 750 grams. The majority of infants born at less than 750 grams die within the first year of life; thus, these births contribute disproportionately to overall IMR. Increases in births at less than 750 grams occurred fornon-Hispanic white, non-Hispanic black, and Hispanic women. Most of the increase occurred among mothers 20 to 34 years of age. Although multiple births contributed disproportionately, most of the increase in births at less than 750 grams occurred among singletons. Three hypotheses were evaluated to assess their possible impact on the increase in less than 750-gram births: possible changes in (1) the reporting of births or fetal deaths, (2) the risk profile of births, and (3) medical management of pregnancy. Although each of these factors may have contributed to the increase, the relative effects of these and other factors remain unclear. More detailed studies are needed to further explain the 2001-2002 infant mortality increase.     

Birthweight, preterm births and neonatal mortality in Belgium and the United States

Summary. Belgium is known to have a lesser low birthweight rate and a lower infant mortality rate than the United States. We used previously unpublished data to show that beneath this comparison lies a more complicated picture. Singleton live birth certificates for 1986-67 were analysed. Despite a lower mean birthweight in Belgium (3360 g) than in the United States (3420 g), Belgium had fewer (4.9%) low birthweight infants than the US (5.9%) because of fewer preterm births (4.4 vs. 9.3%). Consistent with the excess of preterm births in the US, the residual distribution of birthweight was smaller in Belgium (2.2% vs. 3.1%). Whereas neonatal mortality was 4.8/1000 in Belgium and 5.6/1000 in the US, birthweight-specific neonatal mortality was higher in Belgium. The challenge for Belgium is to improve the survival of newborns regardless of their birthweight. In the US, the task is to eliminate the excess of small preterm infants.     

Neonatal respiratory distress syndrome in Karachi: some epidemiological considerations

Although respiratory distress syndrome (RDS) is a leading cause of neonatal morbidity and mortality in the west, there are few data on the prevalence and spectrum of RDS from developing countries. Available evidence suggests that the disorder may be less common than the overall 1% incidence reported from developed countries. In a prospective study of the prevalence of RDS in a consecutive 10 134 births at the Aga Khan University Hospital, we documented the disorder in 127 (1.2% births), with a prevalence of 12.8% among low birthweight infants. The overall mortality for this group was 39%, with the highest mortality rate (68%) among newborn infants 1000 g birthweight. Our data from a large and relatively well-nourished hospital-born population in Karachi suggest that RDS is a significant cause of morbidity and mortality in preterm infants with a similar prevalence rate to western figures.     

Associations between Feeding Patterns and Infant Health in China: A Propensity Score Matching Approach

Breastmilk is the optimal food for infants. Feeding pattern is closely related to physical development and health during infancy. Understanding the associations between feeding patterns and health status can inform related policy interventions and advocacy in China. This study aimed to investigate the relationship between infant feeding patterns and health status in China infants. The China National Nutrition and Health Surveillance 2013 was a national-representative cross-sectional study performed particularly for children aged 0–5 years. A total of 3974 infants aged under 1 year were included in the analysis, of whom 1082 (27.2%) made up the formula feeding group, and 2892 (72.8%) made up the breastfeeding group. The associations between feeding patterns and physical development and health were investigated using propensity score matching and multivariable logistic regression models. Among breastfeeding and formula feeding infants aged 9–11 months old, weight-for-age z score was 1.1 ± 1.1 and 0.9 ± 1.3, respectively, and weight-for-length z score was 1.0 ± 1.3 and 0.7 ± 1.4, respectively. Hemoglobin in 0–2, 3–5, 6–8, and 9–11 months old breastfeeding infants was 121.4 ± 15.2 g/L, 117.1 ± 13.0 g/L, 113. 9 ± 11.9 g/L, and 114.4 ± 14.0 g/L, while in 0–2, 3–5, 6–8, and 9–11 months formula feeding infants was 116.3 ± 14.8 g/L, 120.4 ± 11.3 g/L, 119.8 ± 11.2 g/L, and 120.0 ± 11.5 g/L, respectively. Breastfeeding was associated with lower risk of respiratory disease (OR: 0.79; 95% CI: 0.64, 0.99) and diarrhea (OR: 0.75; 95% CI: 0.57, 0.98). Breastfeeding could slightly improve infant physical development, and had a protective effect on the diarrheal and respiratory diseases. Infants aged 3–11 months who were breastfeeding showed lower hemoglobin than that of formula-fed infants and thus should increase intake of iron rich complementary foods.     

Pregnancy outcome in women working as dentists,dental assistants or dental technicians

Summary Pregnancy outcome in women with work in dentistry was studied using various central health registries. A total of 8157 infants born of dentists, dental assistants, or dental technicians in 1976 or 1982–1986 in Sweden were studied with respect to perinatal survival, low birthweight, and malformations and compared with all births. The only deviating finding was that of a significantly low perinatal death rate. Specifically, no increase in a risk for spina bifida was seen and the upper 95% confidence limit for the risk ratio was 2.1. A study was also made of hospitalized spontaneous abortions in women with these occupations in the years 1980–1981. No significant deviations from expected values were found. In a small study of only 78 such pregnancies in 1964–1965, no increase in spontaneous abortion rate was seen. Only one infant was malformed (anencephaly): both its parents worked as dental technicians. None of the mothers of 220 infants with a neural tube defect born in 1965–1967 in Sweden was a dentist. We find no indications that this occupation represents a significant reproduction hazard at the present time in Sweden.