Showing papers in "Paediatric and Perinatal Epidemiology in 2008"

Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence.

Abstract: Prenatal maternal stress (PNMS) has been linked with adverse health outcomes in the offspring through experimental studies using animal models and epidemiological studies of human populations The purpose of this review article is to establish a parallel between animal and human studies, while focusing on methodological issues and gaps in knowledge The review examines the quality of recent evidence for prevailing PNMS theoretical models, namely the biopsychosocial model for adverse pregnancy outcomes and the fetal programming model for chronic diseases The investigators used PubMed (2000-06) to identify recently published original articles in the English language literature A total of 103 (60 human and 43 animal) studies were examined Most human studies originated from developed countries, thus limiting generalisability to developing nations Most animal studies were conducted on non-primates, rendering extrapolation of findings to pregnant women less straightforward PNMS definition and measurement were heterogeneous across studies examining similar research questions, thus precluding the conduct of meta-analyses In human studies, physical health outcomes were often restricted to birth complications while mental health outcomes included postnatal developmental disorders and psychiatric conditions in children, adolescents and adults Diverse health outcomes were considered in animal studies, some being useful models for depression, schizophrenia or attention deficit hyperactivity disorder in human populations The overall evidence is consistent with independent effects of PNMS on perinatal and postnatal outcomes Intervention studies and large population-based cohort studies combining repeated multi-dimensional and standardised PNMS measurements with biomarkers of stress are needed to further understand PNMS aetiology and pathophysiology in human populations

Active and passive maternal smoking during pregnancy and the risks of low birthweight and preterm birth: the Generation R Study.

Abstract: The objective of this study was to examine the associations between active and passive smoking in different periods of pregnancy and changing smoking habits during pregnancy, with low birthweight and preterm birth. The study was embedded in the Generation R Study, a population-based prospective cohort study from early fetal life onwards in Rotterdam, The Netherlands. Active and passive smoking were assessed by questionnaires in early, mid- and late pregnancy. Analyses were based on 7098 pregnant women and their children. Active smoking until pregnancy was ascertained and was not associated with low birthweight and preterm birth. Continued active smoking after pregnancy was also recorded and was associated with low birthweight (adjusted odds ratio 1.75 [95% CI 1.20, 2.56]) and preterm birth (adjusted odds ratio 1.36 [95% CI 1.04, 1.78]). The strongest associations were found for active maternal smoking in late pregnancy. Passive maternal smoking in late pregnancy was associated with continuously measured birthweight (P for trend <0.001). For all active smoking categories in early pregnancy, quitting smoking was associated with a higher birthweight than continuing to smoke. Tendencies towards smaller non-significant beneficial effects on mean birthweight were found for reducing the number of cigarettes without quitting completely. This study shows that active and passive smoking in late pregnancy are associated with adverse effects on weight and gestational age at birth. Smoking in early pregnancy only, seems not to affect fetal growth adversely. Health care strategies for pregnant women should be aimed at quitting smoking completely rather than reducing the number of cigarettes.

Strategies for improving the quality of health care in maternal and child health in low- and middle-income countries: an overview of systematic reviews.

Abstract: There are many systematic reviews of continuing education programmes and educational strategies for quality improvement in health care. Most of the reviewed studies are one-off evaluations rather than impact evaluations with long-term follow-up. There are few systematic reviews of organisational, financial and regulatory interventions, and few high-quality studies. These interventions are probably as or more important than educational strategies, although they are less well evaluated. Few studies have been undertaken in low- and middle-income countries (LMIC) or that address maternal and child health (MCH). Thus, the results of the available studies and reviews need to be interpreted cautiously when applied to LMIC. Interactive workshops, reminders and multifaceted interventions can improve professional practice, and they generally have moderate effects. Educational outreach visits consistently improve prescribing but have variable effects on other behaviours. Audit and feedback interventions have variable effects on professional practice, but most often these are small to moderate effects. Mass-media and patient-mediated interventions may change professional practice. Multifaceted interventions that combine several quality-improvement strategies are also effective but may not be more so than single interventions. While all of these strategies are applicable to MCH in LMIC, the applicability of the results to rural settings, in particular, may be limited. Use of these strategies could exacerbate inequalities, and this should be taken into consideration when planning implementation. Scaling up and sustainability may be difficult to achieve in LMIC contexts and need careful consideration. The use of financial interventions has not been well studied; financial incentives and disincentives may be difficult to use effectively and efficiently, although their impact on practice needs to be considered. Organisational interventions are likely to be important, given that there are often underlying organisational or system problems. Regulatory interventions have not been well evaluated, but may sometimes be both inexpensive and effective. There are no 'magic bullets' or simple solutions for ensuring the quality of health care services. Interventions should be selected or tailored to address the underlying reasons for a failure to deliver effective services. Decision-makers should select the most appropriate interventions for specific problems. This requires a governance structure that clearly assigns responsibility for quality-improvement activities, priority setting, selection and design of interventions, and evaluation.

Comparison of gestational age at birth based on last menstrual period and ultrasound during the first trimester

Abstract: Reported last menstrual period (LMP) is commonly used to estimate gestational age (GA) but may be unreliable. Ultrasound in the first trimester is generally considered a highly accurate method of pregnancy dating. The authors compared first trimester report of LMP and first trimester ultrasound for estimating GA at birth and examined whether disagreement between estimates varied by maternal and infant characteristics. Analyses included 1867 singleton livebirths to women enrolled in a prospective pregnancy cohort. The authors computed the difference between LMP and ultrasound GA estimates (GA difference) and examined the proportion of births within categories of GA difference stratified by maternal and infant characteristics. The proportion of births classified as preterm, term and post-term by pregnancy dating methods was also examined. LMP-based estimates were 0.8 days (standard deviation = 8.0, median = 0) longer on average than ultrasound estimates. LMP classified more births as post-term than ultrasound (4.0% vs. 0.7%). GA difference was greater among young women, non-Hispanic Black and Hispanic women, women of non-optimal body weight and mothers of low-birthweight infants. Results indicate first trimester report of LMP reasonably approximates gestational age obtained from first trimester ultrasound, but the degree of discrepancy between estimates varies by important maternal characteristics.

Placental characteristics and birthweight.

Abstract: Standard gross placental measures capture dimensions relevant to specific placental functions. Our objective was to determine their accountability independent of placental weight for variance in birthweight, an important proxy for intrauterine 'adequacy' in fetal origins studies. The sample consisted of 24 152 singleton liveborn children of the Collaborative Perinatal Project delivered from 34 to 42 completed weeks gestation, with complete data for six placental measures (placental disc shape, umbilical cord length, distance from cord insertion to nearest margin, large diameter, small diameter, placental thickness) and placental weight. Associations between birthweight and placental measures were examined using multiple linear regression. Placental weight alone accounted for 36.6% of birthweight variation; the six other placental measures accounted for 28.1%. Combined, all placental measures accounted for 39.1% of birthweight variation. Seven maternal characteristics (age, height, weight, parity, socio-economic status, cigarette use, and race) were investigated to determine whether their known associations with birthweight were mediated by placental markers. Analysis suggested that the impact of all maternal characteristics except smoking was consistent with mediation by placental characteristics.

Four million neonatal deaths: counting and attribution of cause of death

Abstract: Each year there are an estimated four million neonatal deaths and at least 3.2 million stillbirths. Three-quarters of the world's neonatal deaths are counted only through five-yearly retrospective household surveys. Without these surveys we would have no data, but limitations remain particularly in detecting deaths on the first day of life. Comparable reliable neonatal cause of death data through vital registration are available for less than 5% of the world's neonatal deaths, necessitating modelled estimates for the majority of the world. Improving the quantity, quality and frequency of data for numbers and causes of neonatal deaths is essential to effectively guide the increasing investments to reduce these deaths. Advancing the data requires general investment in information systems and specific improvements of tools and methods for both household surveys and verbal autopsy, particularly the use of consistent case definitions and hierarchical attribution of cause of death. An important paradigm shift is from historical categories for cause of death ('perinatal causes') to programmatic categories which are consistent with the International Classification of Diseases. If neonatal deaths remain uncounted, they cannot count in policy and in programmes.

Aetiology of stillbirths and neonatal deaths in rural Ghana: implications for health programming in developing countries.

Abstract: In developing countries many stillbirths and neonatal deaths occur at home and cause of death is not recorded by national health information systems. A community-level verbal autopsy tool was used to obtain data on the aetiology of stillbirths and neonatal deaths in rural Ghana. Objectives were to describe the timing and distribution of causes of stillbirths and neonatal deaths according to site of death (health facility or home). Data were collected from 1 January 2003 to 30 June 2004; 20,317 deliveries, 696 stillbirths and 623 neonatal deaths occurred over that time. Most deaths occurred in the antepartum period (28 weeks gestation to the onset of labour) (33.0%). However, the highest risk periods were during labour and delivery (intrapartum period) and the first day of life. Infections were a major cause of death in the antepartum (10.1%) and neonatal (40.3%) periods. The most important cause of intrapartum death was obstetric complications (59.3%). There were significantly fewer neonatal deaths resulting from birth asphyxia in the home than in the health facilities and more deaths from infection. Only 59 (20.7%) mothers of neonates who died at home reported that they sought care from an appropriate health care provider (doctor, nurse or health facility) during their baby's illness. The results from this study highlight the importance of studying community-level data in developing countries and the high risk of intrapartum stillbirths and infectious diseases in the rural African mother and neonate. Community-level interventions are urgently needed, especially interventions that reduce intrapartum deaths and infection rates in the mother and infant.

Associated factors and consequences of late preterm births: results from the 2004 Pelotas birth cohort

Abstract: Although neonatal and infant mortality rates have fallen in recent decades in Brazil, the prevalence of preterm deliveries has increased in certain regions, especially in the number of late preterm births. This study was planned to investigate: (1) maternal antenatal characteristics associated with late preterm births and (2) the consequences of late preterm birth on infant health in the neonatal period and until age 3 months. A population-based birth cohort was enrolled in Pelotas, Southern Brazil, in 2004. Mothers were interviewed and the gestational age of newborns was estimated through last menstrual period, ultrasound and Dubowitz's method. Preterm births between 34 and 36 completed weeks of gestational age were classified as late preterm births. Only singleton live births from mothers living in the urban area of Pelotas were investigated. Three months after birth, mothers were interviewed at home regarding breast feeding, morbidity and hospital admissions. All deaths occurring in the first year of life were recorded. A total of 447 newborns (10.8%) were late preterms. Associations were observed with maternal age <20 years (prevalence ratio [PR] 1.3 [95% CI 1.1, 1.6]), absence of antenatal care (PR 2.4 [1.4, 4.2]) or less than seven prenatal care visits, arterial hypertension (PR 1.3 [1.0, 1.5]), and preterm labour (PR 1.6 [1.3, 1.9]). Compared with term births, late preterm births showed increased risk of depression at birth (Relative risk [RR] 1.7 [1.3, 2.2]), perinatal morbidity (RR 2.8 [2.3, 3.5]), and absence of breast feeding in the first hours after birth (PR 0.9 [0.8, 0.9]). RRs for neonatal and infant mortality were, respectively, 5.1 [1.7, 14.9] and 2.1 [1.0, 4.6] times higher than that observed among term newborns. In conclusion, in our setting, the prevention of all preterm births must be a priority, regardless of whether early or late.

Assays with lower detection limits: implications for epidemiological investigations.

Abstract: Summary Epidemiological investigations of health effects related to chronic low-level exposures or other circumstances often face the difficult task of dealing with levels of biomarkers that are hard to detect and/or quantify. In these cases instrumentation may not adequately measure biomarker levels. Reasons include a failure of instruments to detect levels below a certain value or, alternatively, interference by error or ‘noise’. Current laboratory practice determines a ‘limit of detection (LOD)’, or some other detection threshold, as a function of the distribution of instrument ‘noise’. Although measurements are produced above and below this threshold in many circumstances, rather than numerical data, all points observed below this threshold may be reported as ‘not detected’. The focus of this process of determination of the LOD is instrument noise and avoiding false positives. Moreover, uncertainty is assumed to apply only to the lowest values, which are treated differently from above-threshold values, thereby potentially creating a false dichotomy. In this paper we discuss the application of thresholds to measurement of biomarkers and illustrate how conventional approaches, though appropriate for certain settings, may fail epidemiological investigations. Rather than automated procedures that subject observed data to a standard threshold, the authors advocate investigators to seek information on the measurement process and request all observed data from laboratories (including the data below the threshold) to determine appropriate treatment of those data.

Diagnostic accuracy of verbal autopsies in ascertaining the causes of stillbirths and neonatal deaths in rural Ghana.

Abstract: This study evaluated the diagnostic accuracy of a verbal autopsy (VA) tool in ascertaining the causes of stillbirths and neonatal deaths in rural Ghana and was nested within a community-based maternal vitamin A supplementation trial (ObaapaVitA trial). All stillbirths and neonatal deaths between 1 January 2003 and 30 June 2004 were prospectively included. Community VAs were carried out within 6 months of death and were classified with a primary cause of death by three experienced paediatricans. The reference standard diagnosis was obtained by the study paediatrician in 4 district hospitals in the study area. There were 20 317 deliveries, 661 stillbirths and 590 neonatal deaths with a VA diagnosis in the study population. A total of 311 stillbirths and 191 neonatal deaths had both a VA and a hospital reference standard diagnosis. The VA performed poorly for stillbirth diagnoses such as congenital abnormalities and maternal haemorrhage. Accuracy was higher for intrapartum obstetric complications and antepartum maternal disease. For neonatal deaths, sensitivity was >60% for all major causes; specificity was 76% for birth asphyxia but >85% for prematurity and infection. Overall, VA diagnostic accuracy was higher than expected in this rural African setting. Our classification system was based on the expected public health importance of the individual causes of death, differing implications for intervention and the ability to distinguish between the individual causes in low-resource settings. We believe this system was easier to use than traditional approaches and resulted in high precision and accuracy. However, further simplifications are needed to allow use of the World Health Organisation VA in routine child health programmes. The diagnostic accuracy of the VA tool should also be assessed in other regions and in multicentre studies.

Milk feeding and dietary patterns predict weight and fat gains in infancy

Abstract: Current guidelines recommend that infants are exclusively breast fed for the first 6 months of life, with particular solid foods being gradually introduced from 6 months. Our objective was to compare the growth of infants whose feeding most closely followed current guidelines with the growth of infants with other feeding practices. Participants were 1740 infants in a prospective cohort study in Southampton, UK. At 6 and 12 months, infants' milk feeding was recorded, diets assessed using food frequency questionnaires (FFQ), and anthropometry performed. Principal components analysis was used to identify patterns of foods in the diet using the food intakes assessed by the FFQs. Two patterns ('infant guidelines' and 'adult foods') explained most variance in infant diet at 6 and 12 months of age. The main outcomes were conditional growth in weight, length and skinfold thickness from 0-6 and 6-12 months. Infants who were breast fed from 0-6 months gained weight, length and adiposity more slowly than formula-fed infants, independent of age at introduction of solids and maternal factors: compared with infants who were breast fed from 0-6 months, formula-fed infants gained 0.21 standard deviation scores (SDS) in weight [95% confidence interval (CI) 0.00, 0.42]. Infants whose dietary pattern was most similar to current feeding guidelines, with high frequencies of fresh fruit and vegetables, home-prepared foods and breast milk, gained weight and skinfold thickness more rapidly from 6 to 12 months than other infants, independent of milk feeding, age at introduction of solids and maternal factors. Compared with infants in the lowest quarter, infants in the highest 'infant guidelines' score quarter gained 0.24 SDS [95% CI 0.06, 0.43] in weight and 0.26 SDS [95% CI 0.07, 0.45] in skinfold thickness. Conversely, infants whose diets had the highest frequencies of breads and processed foods gained weight less rapidly from 6 to 12 months than other infants. The extent to which the patterns of diet and growth we have described will influence the current or later health of infants is unknown. We are following up the infants in this study to assess the impact of these patterns beyond the first year of life. These associations should also be examined in other settings and populations.

Prenatal polychlorinated biphenyl exposures in eastern Slovakia modify effects of social factors on birthweight.

Abstract: Polychlorinated biphenyls (PCB) were widely used for industrial purposes and consumer products, but because of their toxicity, production was banned by most industrialised countries in the late 1970s. In eastern Slovakia, they were produced until 1985. During 2002-04, a birth cohort of mothers (n = 1057) residing in two Slovak districts was enrolled at delivery, and their specimens and information were collected after birth. Congeners of PCBs were measured in maternal serum by high-resolution gas chromatography with electron capture detection. In this study, we used multiple linear regression to examine the effects of prenatal PCB exposure on birthweight adjusted for gestational age, controlling for inter-pregnancy interval, and maternal smoking, age, education, ethnicity, pre-pregnancy body mass index and height. The association between total maternal serum PCB levels and birthweight was not statistically significant. However, an interaction model indicated that maternal PCB concentrations were associated with lower birthweight in Romani boys. Based on the fitted regression model, the predicted birthweight of Romani boys at the 90th percentile of maternal PCBs (12.8 ng/mL) was 133 g lower than the predicted birthweight at the 10th percentile of maternal PCBs (1.6 ng/mL). This is a similar magnitude of effect to that observed for maternal smoking and birthweight. These results suggest that higher levels of PCBs in maternal blood sera may inhibit growth in boys, particularly in those already affected by social factors related to ethnicity. This study is consistent with previous findings that boys are more susceptible than girls to growth restriction induced by in utero organochlorine exposures, and further indicates that high PCBs may magnify the influence of social disadvantage in this vulnerable group of boys.

Influences of study design and location on the relationship between particulate matter air pollution and birthweight.

Abstract: A large number of studies have identified a relationship between particulate matter air pollution and birthweight. Although reported associations are small and varied, they have been identified in studies from places around the world. Exposure assignment, covariates and study inclusion criteria vary among studies. To examine the effect of these and other study characteristics on associations between particulate matter and birthweight, US birth records for singletons delivered at 40 weeks gestation in 2001-03 during the months of March, June, September and December were linked to quarterly estimates of pollution exposure, both particulate matter exposure and exposure to multiple pollutants, by county of residence and month of birth. Annual, 9-month and trimester-specific exposures were assigned. Among births linked to particulate matter exposure there was a small association between coarse particle exposure and birthweight (beta -13 g per 10 microg/m(3) increase [95% CI -18.3 g, -7.6 g]) after controlling for maternal factors; this association was attenuated slightly and remained statistically significant after further adjustment for contextual factors, year of birth, region, or urban-rural status. The associations were slightly weaker among births linked to multiple pollutant exposure than among births linked to just particulate matter exposure. The association varied markedly by region, ranging from a decrement of 43 g per 10 microg/m(3)[95% CI -58.6 g, -27.6 g] in the north-west to a null association in the south-west. Trimester findings were smaller, yet remained significant and varied regionally. The association between fine particle exposure and birthweight varied considerably, with an overall small positive association that became null after control for region. This study found that wide regional differences in association may contribute to the varied published findings. The association between coarse particle exposure and birthweight appeared robust, if small; fine particles had no overall association with birthweight.

Associations of birthweight and infant growth with body composition at age 15--the COMPASS study.

Abstract: Size at birth and postnatal growth have been positively associated with obesity in adulthood. However, associations between postnatal growth and body composition later in life have rarely been studied. The overall purpose was to explore the associations between birthweight, weight gain during first year of life and height, weight, body mass index, fat free mass index (FFMI), fat mass index, % fat mass (FM) and waist circumference in adolescence. The COMPASS study is a population-based study of adolescents from a well-defined area in Stockholm County, Sweden. Birth characteristics and weight during childhood were collected from registers and child health centre records, and body composition at age 15 years was measured by bioelectric impedance by trained nurses. Complete data were available for 2453 adolescents. Associations between predictor and outcome variables were assessed with linear regression modelling. Birthweight was positively associated with all outcome variables, except for %FM among girls. FFMI increased by 0.49 kg/m(2)[95% CI 0.34, 0.63] (boys) and 0.25 kg/m(2)[0.12, 0.38] (girls) per 1 SD increase in birthweight. Increased weight gain in infancy showed strong, positive associations with all measures of body composition. FFMI increased by 0.73 kg/m(2)[0.60, 0.87] (boys) and 0.63 kg/m(2)[0.50, 0.76] (girls) per unit increase in weight z-score during first year of life. The effect of increased weight gain in infancy was not modified by birthweight. Birthweight and postnatal growth were both positively related to body composition in adolescence. Increased weight gain during the first year of life had stronger effect than prenatal growth, suggesting infancy to be a more critical period.

To pool or not to pool, from whether to when: applications of pooling to biospecimens subject to a limit of detection.

Abstract: Pooling of biological specimens has been utilised as a cost-efficient sampling strategy, but cost is not the unique limiting factor in biomarker development and evaluation. We examine the effect of different sampling strategies of biospecimens for exposure assessment that cannot be detected below a detection threshold (DT). The paper compares use of pooled samples to a randomly selected sample from a cohort in order to evaluate the efficiency of parameter estimates. The proposed approach shows that a pooling design is more efficient than a random sample strategy under certain circumstances. Moreover, because pooling minimises the amount of information lost below the DT, the use of pooled data is preferable (in a context of a parametric estimation) to using all available individual measurements, for certain values of the DT. We propose a combined design, which applies pooled and unpooled biospecimens, in order to capture the strengths of the different sampling strategies and overcome instrument limitations (i.e. DT). Several Monte Carlo simulations and an example based on actual biomarker data illustrate the results of the article.

Depressive symptoms during pregnancy in relation to fish consumption and intake of n-3 polyunsaturated fatty acids.

Abstract: An inverse association between depression and the n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), primarily obtained from fish consumption, is observed in both observational and experimental research and is biologically plausible. Study objectives were to examine whether prenatal depressive symptoms were associated with lower intakes of fish or EPA+DHA. Pregnant women (n = 2394) completed a telephone interview between 10 and 22 weeks' gestation in London, Ontario, 2002-05. Depressive symptoms were measured using the Center for Epidemiologic Studies - Depression Scale (CES-D). Intakes of fish and EPA+DHA were measured using a validated food-frequency questionnaire. Sequential multiple regression was used to examine associations of depressive symptoms with intake of fish and EPA+DHA, respectively, while controlling for sociodemographic, health and lifestyle variables. The mean CES-D score was 9.9 (SD 8.0). Intake of EPA+DHA was dichotomised at the median value of 85 mg/day. Fish consumption and intake of EPA+DHA were not associated with prenatal depressive symptoms after adjustment for confounders; however, depressive symptoms were significantly higher for lower intakes of EPA+DHA among current smokers and women of single/separated/divorced marital status. The adjusted difference in CES-D scores between intake categories of EPA+DHA was -2.4 [95% CI -4.2, -0.4] for current smokers and -2.8 [95% CI -5.2, -0.4] for women of single marital status. Although pregnant women may be at risk for low concentrations of EPA and DHA, an association between low intakes of EPA+DHA and increased depressive symptoms was only observed among current smokers and women of single marital status.

Intracluster correlation coefficients from the 2005 WHO Global Survey on Maternal and Perinatal Health: Implications for implementation research.

Abstract: Cluster-based studies involving aggregate units such as hospitals or medical practices are increasingly being used in healthcare evaluation. An important characteristic of such studies is the presence of intracluster correlation, typically quantified by the intracluster correlation coefficient (ICC). Sample size calculations for cluster-based studies need to account for the ICC, or risk underestimating the sample size required to yield the desired levels of power and significance. In this article, we present values for ICCs that were obtained from data on 97,095 pregnancies and 98,072 births taking place in a representative sample of 120 hospitals in eight Latin American countries. We present ICCs for 86 variables measured on mothers and newborns from pregnancy to the time of hospital discharge, including 'process variables' representing actual medical care received for each mother and newborn. Process variables are of primary interest in the field of implementation research. We found that overall, ICCs ranged from a minimum of 0.0003 to a maximum of 0.563 (median 0.067). For maternal and newborn outcome variables, the median ICCs were 0.011 (interquartile range 0.007-0.037) and 0.054 (interquartile range 0.013-0.075) respectively; however, for process variables, the median was 0.161 (interquartile range 0.072-0.328). Thus, we confirm previous findings that process variables tend to have higher ICCs than outcome variables. We demonstrate that ICCs generally tend to increase with higher prevalences (close to 0.5). These results can help researchers calculate the required sample size for future research studies in maternal and perinatal health.

Maternal smoking demographic and lifestyle factors in relation to daughter’s age at menarche.

Abstract: A previous study suggested a younger age at menarche (AAM) among daughters of heavy prenatal smokers especially among non-Whites. The present study was designed to evaluate that association in another population and to examine other factors that may be related to AAM. We analysed data from the Collaborative Perinatal Project a nationwide longitudinal study of pregnant women and their children conducted in 1959-66. At three sites with a predominance of Black participants (80%) AAM was ascertained in the offspring when they were young adults. We included data on 1556 daughters who had a mean AAM of 12.7 years (standard deviation 1.8). Amount smoked by the mothers was obtained from a baseline interview and subsequent prenatal visits. Regression models were run including maternal smoking and other covariates for only the prenatal period as well as in models with some childhood characteristics. In the prenatal factor model younger mean AAM in daughters was found with maternal characteristics of earlier AAM being married and of lower parity. Examining childhood variables earlier AAM was found among girls with few or no siblings or with higher socio-economic status. Unlike our previous findings mean AAM was later in daughters of heavy smokers (20+ cigarettes/day) with a delay of 0.31 years [95% confidence interval (CI) 0.008 0.61] or about 3.7 months in the prenatal model and 0.34 years [95% CI -0.02 0.66] in the model with childhood variables included. The pattern was consistent by race. A number of prenatal and childhood factors related to AAM were identified that should be considered when examining exogenous exposures in relation to pubertal onset. (authors)

Neonatal jaundice: a risk factor for infantile autism?

Abstract: In a previous study, we found that infants transferred to a neonatal ward after delivery had an almost twofold increased risk of being diagnosed with infantile autism later in childhood in spite of extensive controlling of obstetric risk factors. We therefore decided to investigate other reasons for transfer to a neonatal ward, in particular hyperbilirubinaemia and neurological abnormalities. We conducted a population-based matched case-control study of 473 children with autism and 473 matched controls born from 1990 to 1999 in Denmark. Cases were children reported with a diagnosis of infantile autism in the Danish Psychiatric Central Register. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals [CI] and likelihood ratio tests were used to test for effect modification. We found an almost fourfold risk for infantile autism in infants who had hyperbilirubinaemia after birth (OR 3.7 [95% CI 1.3, 10.5]). In stratified analysis, the association appeared limited to term infants (>or=37 weeks gestation). A strong association was also observed between abnormal neurological signs after birth and infantile autism, especially hypertonicity (OR 6.7 [95% CI 1.5, 29.7]). No associations were found between infantile autism and low Apgar scores, acidosis or hypoglycaemia. Our findings suggest that hyperbilirubinaemia and neurological abnormalities in the neonatal period are important factors to consider when studying causes of infantile autism.

Maternal diet and the risk of hypospadias and cryptorchidism in the offspring

Abstract: Male genital tract birth defects have been associated in previous studies with several prenatal exposures to environmental and dietary risk factors. The purpose of this study was to explore the association between hypospadias and cryptorchidism, and the dietary habits of an agricultural population in Italy. A population-based case-control study was conducted in the Sicilian Province of Ragusa. Cases (n = 90) and controls (n = 202) included births for the period 1998-2002. Data on dietary habits of the mothers, as well as health-related social, occupational and environmental exposures prior to and during the index birth, were collected through interviews. Adjusted odds ratios (OR) were calculated by logistic regression after adjustment for confounding variables. Increased ORs were observed for mothers of children with hypospadias who, during pregnancy, frequently consumed fish (OR = 2.33 [95% confidence interval (CI) 1.03, 5.31]) and market-purchased fruit (OR = 5.10 [95% CI 1.31, 19.82]). For cryptorchidism, increased risk was observed in mothers consuming liver (OR = 5.21 [95% CI 1.26, 21.50]), and smoked products (OR = 2.46 [95% CI 1.15, 5.29]). For the two malformations pooled together, increased risk was associated with maternal consumption of liver (OR = 4.38 [95% CI 1.34, 14.26]) and with frequent consumption of wine (OR = 1.98 [95% CI 1.01, 3.86]). This study suggests that some maternal dietary factors may play a role in the development of congenital defects of the male reproductive tract. In particular, our data indicate that further research may be warranted on the endocrine-disrupting effects resulting from the bioaccumulation of contaminants (fish, liver), pesticides (marketed fruit, wine) and/or potentially toxic food components (smoked products, wine, liver).

Degree of rural isolation and birth outcomes

Abstract: Little is known about how birth outcomes vary in rural areas by degree of rural isolation. We conducted a retrospective cohort study of all births in Quebec, 1991-2000 to assess birth outcomes by the degree of rural isolation according to metropolitan influence as measured by work force commuting flows between rural and urban areas. Compared with urban areas, crude risks of preterm birth, small-for-gestational age birth, stillbirth, neonatal death and postneonatal death were similar in rural areas with strong metropolitan influence, but were significantly higher for preterm birth, stillbirth and postneonatal death in rural areas with weak or no metropolitan influence, and for neonatal death in rural areas with no metropolitan influence. Adjustment for maternal characteristics (age, mother tongue, education, marital status, parity, plurality and infant sex) attenuated the associations. The adjusted odds ratios [95% confidence intervals] were 1.36 [1.12, 1.64] for stillbirth in rural areas with weak metropolitan influence, 1.63 [1.14, 2.32] for neonatal death in rural areas with no metropolitan influence, 1.78 [1.21, 2.63] and 1.37 [1.07, 1.75] for postneonatal death in rural areas with weak and no metropolitan influence, respectively. Much higher neonatal death rates were observed for preterm or low-birthweight babies in rural areas with no metropolitan influence, suggesting inadequate access to optimal neonatal care. We conclude that birth outcomes in rural areas differ according to the degree of rural isolation. Fetuses and infants of mothers from rural areas with weak or no metropolitan influence are particularly vulnerable to the risks of death during the perinatal and postnatal periods.

The prevalence of preterm birth and season of conception.

Abstract: Preterm birth is a major obstetric problem. An exploration of the season of conception in relation to preterm birth may provide direction in the search for risk factors. We conducted a retrospective cohort study of 82 213 singleton livebirths (20-45 weeks' gestation) to 61,630 women at Magee-Womens Hospital, Pittsburgh, PA, from 1995 to 2005. Conception was estimated based on gestational age determined by best obstetric estimate. Fourier series analysis was used to model seasonal trends. Spontaneous preterm birth at <37 weeks was associated with conception season (P < 0.05). The peak prevalence occurred among conceptions in winter and spring (peaking February 23 at 6.9%), with an average trough among late summer/early autumn conceptions (August 25 at 6.2%). The pattern for spontaneous preterm birth <32 weeks was similar (P < 0.05), with the peak on March 13 (1.7%), and nadir on September 12 (1.4%). Results were similar when indicated preterm births were included. These seasonal changes may increase our insight into the role of exposures with seasonal periodicity in the pathophysiology of preterm birth.

Variation in season of birth in singleton and multiple births concordant for autism spectrum disorders

Abstract: Patterns of seasonal variation in births in some neuropsychiatric conditions have been found in previous research; however, no study to date has examined these disorders for seasonal variation in singletons and multiple births separately. This study aimed to determine whether the birth date distribution for individuals with autism spectrum disorders (ASD), including singletons and multiple births, differed from the general population. Two ASD case groups were studied: 907 singletons and 161 multiple births concordant for ASD. Two control groups were obtained from registered births of singletons and multiples. Results of the non-parametric time-series analyses, where day of birth was used, suggested there were three peaks in ASD singletons and ASD concordant multiple births. Roughly, the peaks were in April, June and October for singletons and about 2-4 weeks earlier in multiples. Results from multivariable Poisson regression, where month of birth was used, indicated that ASD concordant multiple births in males tended to be higher than expected in March, May and September (with borderline statistical significance), but were 87% less in December (P < 0.05), as compared with January. Overall, the patterns of relative risk estimates from Poisson regression are similar to findings from the non-parametric time-series approach, but are not exactly congruent. It is important to note that indications of seasonality may be sensitive to the selection of time cut-points and therefore an arbitrary binning of time can either mask existing trends or falsely indicate the presence of a trend. The presence of seasonal trends in ASD singletons and concordant multiple births suggests a role for non-heritable factors operating during the pre- or perinatal period, even among cases with a genetic susceptibility.

Trends in stillbirths, early and late neonatal mortality in rural Bangladesh: the role of public health interventions

Abstract: Trends were examined in a cohort study of stillbirths and early and late neonatal deaths in Matlab, a rural area of Bangladesh between 1975 and 2002, using routinely collected demographic surveillance data. Main outcome measures were stillbirths per 1000 births, early neonatal deaths per 1000 livebirths, and late neonatal deaths per 1000 children surviving after 1 week. We performed a logistic regression examining trends over time and between two areas in the three outcome measures, controlling for the effects of parental education, religion, time, geography, parity, maternal age and birth spacing. There was a marked decline in stillbirths, early and late neonatal mortality over time in both areas, though the pace of decline was somewhat faster in the ICDDR,B (International Centre for Diarrhoeal Disease Research, Bangladesh) service area. Stillbirths declined by 24% overall in the ICDDR,B service area (crude OR comparing 1996-2002 with 1975-81: 0.76 [95% CI 0.68, 0.84]), compared with 15% in the Government service area (crude OR comparing 1996-2002 with 1975-81: 0.85 [0.76, 0.94]). The overall reduction in early and late neonatal mortality comparing the same periods was 39% and 73%, respectively, in the ICDDR,B area, compared with 30% and 63%, respectively, in the Government service area. Adjusting for socio-economic or demographic factors did not substantially alter the time or area differentials. The dramatic decline in neonatal mortality was, in large part, due to a fall in deaths from neonatal tetanus. The pace of decline was faster in the area receiving intense maternal and child health and family planning interventions, but stillbirths, early and late neonatal deaths also declined in the area not receiving such intense attention, suggesting that factors outside the formal health sector play an important role.

Dental caries in 3-year-old children and smoking status of parents.

Abstract: An association has been suggested between environmental tobacco smoke and oral disease. The present study examined the relationship between early childhood caries (ECC) and parental smoking, particularly paternal smoking, using records of 711 36-month-old children. The smoking status of parents as an independent variable was entered in the multivariable logistic regression model for caries experience as the dependent variable with confounders: sex, residential location, and possible risks of ECC such as order of birth, type of main drink, frequency of daily intake of sugar-containing snacks, daily toothbrushing by parents and use of fluoridated toothpaste. About 65% of children were caries free. Children whose parents did not smoke (CN), those in whom only the father smoked (CF), and those whose mother smoked regardless of the smoking status of the father (CM) comprised 33%, 33% and 34% respectively. The adjusted mean number [95% CI] of decayed teeth and caries experience prevalence for CN, CF and CM were 1.2 [0.8, 1.6], 1.6 [1.2, 2.0] and 2.1 [1.7, 2.5], and 25.6%, 35.3% and 45.7% respectively. The relationship between caries experience and parental smoking was significant on multivariable analysis. The adjusted OR [95% CI] of CF and CM relative to CN was 1.52 [1.01, 2.30] and 2.25 [1.51, 3.37] respectively. These results indicate the association of ECC with parental smoking, although the association with paternal smoking was weaker than with maternal smoking.

Ethnic differences in term birthweight: the role of constitutional and environmental factors

Abstract: It is not clear to what extent ethnic differences in the term birthweight distribution are constitutional or pathological. This study explored term birthweight heterogeneity between ethnic groups and the explanatory role of constitutional and environmental factors. As part of a prospective cohort study, the Amsterdam Born Children and their Development study, 8266 pregnant women filled out a questionnaire during early pregnancy. Ethnic groups were categorised as: native Dutch group; first and second generation Surinamese, Antillean, Turkish, Moroccan, Ghanaian and other non-Dutch groups. Only singleton livebirths with >or=37.0 weeks of gestation and with complete data were included for analysis (n = 7118). We performed linear regression analyses to estimate the association between ethnicity and, for gestational age, standardised birthweight at term, adjusted for constitutional (fetal gender, parity, maternal age, maternal height) and environmental (education, cohabitation status, maternal body mass index, smoking, alcohol consumption, depression, work stress) determinants respectively. Mean birthweight ranged from 3223 g (second generation Surinamese newborns) to 3548 g (Dutch newborns). Adjustment for constitutional factors substantially reduced the ethnic differences in birthweight, while adjustment for environmental factors provided little additional explanation. Surinamese [first generation: regression coefficient (b) = -98.3 g, P < 0.001; second generation: b = -159.3 g, P < 0.001], first generation Antillean (b = -102.0 g, P = 0.037), and Ghanaian newborns (b = -120.7 g, P = 0.001) remained significantly smaller than Dutch newborns after adjustment for all determinants. Term birthweight differences between Dutch newborns and Turkish, Moroccan and other non-Dutch newborns were largely explained by constitutional rather than environmental determinants, limiting the need for prevention. Surinamese, Antillean and Ghanaian (mainly black) newborns remained unexplainably smaller after adjustment, leaving the possibility of either unknown constitutional or pathological underlying mechanisms.

Association between perceived security of the neighbourhood and small-for-gestational-age birth.

Abstract: Evidence points to an association between a mother's place of residence and her newborn's health, independent of individual characteristics. Neighbourhood constructs such as immigrant density, deprivation and crime have all been separately associated with birth outcomes. Little research has considered the joint influence of variables representing a spectrum of neighbourhood constructs. Subjective vs. objective measures of neighbourhood constructs (e.g. reported vs. perceived crime) are often not considered. We sought to evaluate the relationship between neighbourhood measures of reported crime, neighbourhood perceived security, immigrant density, material/social deprivation, residential stability and the odds of small-for-gestational-age (SGA) birth in an urban setting in Canada. Neighbourhood was defined as police districts (n = 49). We linked Montreal livebirths 1997-2001 (n = 98 330) to police district crime measures, survey data on perceived security, and 2001 census data. We used multi-level analysis to calculate odds ratios (OR) for neighbourhood effects on SGA birth accounting for individual characteristics. Mothers residing in neighbourhoods with the most favourable perception had a lower odds of SGA birth than neighbourhoods with the least favourable perception [OR 0.87, 95% CI 0.77, 0.97]. Mothers in neighbourhoods with lower proportions of immigrants had lower odds of SGA birth relative to neighbourhoods with the highest proportion of immigrants. Reported crime, residential stability and material/social deprivation (accounting for neighbourhood perception) were not associated with SGA birth. Immigrant density and subjective perceptions of neighbourhood security are associated with SGA birth. Public health strategies to improve fetal growth should target neighbourhoods with low perceived security and high immigrant density.

Pre-conception counselling in primary care: prevalence of risk factors among couples contemplating pregnancy

Abstract: The outcome of pregnancy can be influenced by several risk factors. Women who are informed about these risks during pre-conception counselling (PCC) have an opportunity to take preventive measures in time. Several studies have shown that high-risk populations have a high prevalence of such risk factors. However, prevalence in the general population, which is assumed to be low risk, is largely unknown. We therefore provided a systematic programme of PCC for the general population and studied the prevalence of risk factors using the risk-assessment questionnaire which was part of the PCC. None of the couples reported no risk factors at all and only 2% of the couples reported risk factors for which written information was considered to be sufficient. Therefore, 98% of all couples reported one or more risk factors for which at least personal counselling by a general practitioner (GP) was indicated. Many of these factors were related to an unhealthy lifestyle. Women with a low level of education reported more risk factors than women with a high level of education. There is a great need for PCC as shown by the fact that almost all couples reported risk factors for which personal counselling was indicated. Pre-conception counselling may reduce the risk of adverse pregnancy outcome by enabling couples to avoid these risks. PCC can be provided by GPs, who have the necessary medical knowledge and background information to counsel couples who wish to have a baby. © 2008 The Authors.

Screening for developmental problems at primary care level: a field programme in San Isidro, Argentina.

Abstract: Information on prevalence and type of problems of psychomotor development (PPD) is necessary for implementation of specific care programmes at field level. With the purpose of obtaining this information a screening test the Prueba Nacional de Pesquisa (PRUNAPE) for PPD was implemented in three health centres in San Isidro a city near Buenos Aires attended by different socio-economic groups: centres A and B were located in the inner city and C in a middle-class area. The test was administered by three previously trained paediatricians to 839 apparently healthy children aged 0-5 years. The failure rates were 24% 19% and 16% in centres A B and C respectively (20% in total). Out of the 170 children failing the test and referred to hospital for diagnosis and treatment only 96 complied and went through a series of studies carried out by a previously prepared multidisciplinary team. With the exception of children who failed the Battelle test [classified as Global Developmental Delay (GDD)] finaldiagnoses were classified according to Diagnostic and Statistical Manual of Mental Disorders 4th edition: GDD (60 children) pervasive developmental disorders (11) communication disorders (10) motor disorders (6 of whom 2 were with cerebral palsy) attention deficit disorders (5) attachment disorders (2) normal children (3). Co-morbidity was present in 22 affected children. Forty-three per cent of children failing the test did not attend hospital or did not complete studies because of major social and family problems the family not living in the area or the parents preferring to consult their own paediatrician. Health centres and children not selected in a randomised way and a significant proportion of them not complying with the indication of hospital referral were major sources of bias so that PPD prevalences positive and negative predictive values should be interpreted with great caution. Further studies accounting for these sources of bias are needed to confirm the observed prevalence of PPD. Training of health personnel at hospital and health centre level priority settings and operational research to evaluate effectiveness of treatments and care delivery systems at field level are necessary in Argentina for optimal use of limited healthcare resources. (authors)

Unintended pregnancy rates among a US military population.

Abstract: Unintended pregnancy among military women influences their lives and has implications for troop readiness and deployment. The purpose of this study was to identify the prevalence of unintended pregnancy in the US Army and assess the variables associated with unintended pregnancy. Using a cross-sectional design, 212 female soldiers who delivered viable infants at Darnall Army Community Hospital, Fort Hood, Texas from 1 June 1998 to 6 October 1998 completed a self-administered survey on pregnancy intention and sociodemographic factors. Approximately 35% of the infants were intended, 51% were unintended and 14% were ambivalent, resulting in 65% not intended, a rate consistent with the upper level of civilian communities. Factors associated univariably with unintended pregnancy included being unmarried, being in the lower enlisted rank, having less than a college degree, and living in the barracks. This study shows the importance of developing programmes and policies that address pregnancy among military personnel.