Socio-economic disparities in pregnancy outcome: why do the poor fare so poorly?

Subjective effect of September 11, 2001 among pregnant women: is cumulative history of interpersonal violence important?

Prior history of trauma may sensitize individuals to subsequent trauma, including terrorist attacks. Using a convenience sample of secondary, cross-sectional data, pregnant women were grouped based on lifetime interpersonal violence history. Cumulative risk theory was used to evaluate the association of lifetime interpersonal violence history and subjective impact of the September 11, 2001 (9/11) terrorists attacks. Using hierarchical linear regression, cumulative risk theory was partially supported. Women with a history of only one type of interpfersonal violence reported greater effect of 9/11 than did women without a history, but women with both types of violence did not report a greater effect of 9/11 compared to women endorsing history of one type. These data corroborate the literature in that level of exposure to terrorist-related trauma predicts subjective reaction to the attacks. Future research with a larger sample and standardized instruments is warranted.

Is maternal smoking during early pregnancy a risk factor for all low birth weight infants?

BACKGROUND

Low birth weight (LBW) infants do not form a homogeneous group; LBW can be caused by prematurity or poor fetal growth manifesting as small for gestational age (SGA) infants or intrauterine growth retardation. We aimed to clarify the relationship of maternal smoking with both SGA and preterm LBW infants.

METHODS

The study population comprised pregnant women who registered at the Koshu City between January 1, 1995, and December 31, 2000, and their children. We performed multivariate analyses using multiple logistic regression models to clarify the relationship of maternal smoking during pregnancy with the SGA outcome and preterm birth in LBW infants.

RESULTS

In this study period, 1,329 pregnant women responded to questionnaires, and infant data were collected from 1,100 mothers (follow-up rate: 82.8%). The number of LBW infants was 81 (7.4%). In this cohort, maternal smoking during early pregnancy was associated with LBW and the SGA outcome. Maternal smoking during early pregnancy was a risk factor for LBW with SGA outcome and for LBW with full-term birth. However, it was not a risk factor for LBW with appropriate weight for gestational age (AGA) and LBW with preterm birth.

CONCLUSION

These results suggested that LBW with AGA and LBW with preterm birth were associated with other risk factors that were not considered in this study, such as periodontal disease. For the prevention of LBW, not only abstinence from smoking during pregnancy but also other methods such as establishing a clinical setting should be adopted.

Inadequate prenatal care and its association with adverse pregnancy outcomes: a comparison of indices

Background

The objectives of this study were to determine rates of prenatal care utilization in Winnipeg, Manitoba, Canada from 1991 to 2000; to compare two indices of prenatal care utilization in identifying the proportion of the population receiving inadequate prenatal care; to determine the association between inadequate prenatal care and adverse pregnancy outcomes (preterm birth, low birth weight [LBW], and small-for-gestational age [SGA]), using each of the indices; and, to assess whether or not, and to what extent, gestational age modifies this association.

Methods

We conducted a population-based study of women having a hospital-based singleton live birth from 1991 to 2000 (N = 80,989). Data sources consisted of a linked mother-baby database and a physician claims file maintained by Manitoba Health. Rates of inadequate prenatal care were calculated using two indices, the R-GINDEX and the APNCU. Logistic regression analysis was used to determine the association between inadequate prenatal care and adverse pregnancy outcomes. Stratified analysis was then used to determine whether the association between inadequate prenatal care and LBW or SGA differed by gestational age.

Results

Rates of inadequate/no prenatal care ranged from 8.3% using APNCU to 8.9% using R-GINDEX. The association between inadequate prenatal care and preterm birth and LBW varied depending on the index used, with adjusted odds ratios (AOR) ranging from 1.0 to 1.3. In contrast, both indices revealed the same strength of association of inadequate prenatal care with SGA (AOR 1.4). Both indices demonstrated heterogeneity (non-uniformity) across gestational age strata, indicating the presence of effect modification by gestational age.

Conclusion

Selection of a prenatal care utilization index requires careful consideration of its methodological underpinnings and limitations. The two indices compared in this study revealed different patterns of utilization of prenatal care, and should not be used interchangeably. Use of these indices to study the association between utilization of prenatal care and pregnancy outcomes affected by the duration of pregnancy should be approached cautiously.

Learning from a Rapid Health Impact Assessment of a proposed maternity service reconfiguration in the English NHS

BACKGROUND

Within many parts of the country, the NHS is undertaking reconfiguration of services. Such proposals can prove a tipping point and provoke public protest, often with significant involvement of local and national politicians. We undertook a rapid Health Impact Assessment (HIA) of a proposed reconfiguration of maternity services in Huddersfield and Halifax in England. The aim of the HIA was to help the PCT Boards to assess the reconfiguration's possible consequences on access to maternity services, and maternal and infant health outcomes across different socio-economic groups in Kirklees. We report on the findings of the HIA and the usefulness of the process to decision making.

METHODS

This HIA used routine maternity data for 2004-2005 in Huddersfield, in addition to published evidence. Standard HIA techniques were used.

RESULTS

We re-highlighted the socio economic differences in smoking status at booking and quitting during pregnancy. We focused on the key concerns of the public, that of adverse obstetric events on a Midwife Led Unit (MLU) with distant obstetric cover. We estimate that twenty percent of women giving birth in a MLU may require urgent transfer to obstetric care during labour. There were no significant socio economic differences. Much of the risk can be mitigated though robust risk management policies. Additional travelling distances and costs could affect lower socio-economic groups the greatest because of lower car ownership and geographical location in relation to the units. There is potential that with improved community antenatal and post natal care, population outcomes could improve significantly, the available evidence supports this view.

CONCLUSION

Available evidence suggests that maternity reconfiguration towards enhanced community care could have many potential benefits but carries risk. Investment is needed to realise the former and mitigate the latter. The usefulness of this Health Impact Assessment may have been impeded by its timing, and the politically charged environment of the proposals. Nonetheless, the methods used are readily applicable to assess the impact of other service reconfigurations. The analysis was simple, not time intensive and used routinely available data. Careful consideration should be given to both the timing and the political context in which an analysis is undertaken.

Maternal and paternal contribution to intergenerational recurrence of breech delivery: population based cohort study

OBJECTIVE

To investigate intergenerational recurrence of breech delivery, with a hypothesis that both women and men delivered in breech presentation contribute to increased risk of breech delivery in their offspring.

DESIGN

Population based cohort study for two generations.

SETTING

Data from the medical birth registry of Norway, based on all births in Norway 1967-2004 (2.2 million births).

PARTICIPANTS

Generational data were provided through linkage by national identification numbers, forming 451,393 mother-offspring units and 295,253 father-offspring units. We included units where both parents and offspring were singletons and offspring were first born, forming 232,704 mother-offspring units and 154,851 father-offspring units for our analyses.

MAIN OUTCOME MEASURE

Breech delivery in the second generation.

RESULTS

Men and women who themselves were delivered in breech presentation had more than twice the risk of breech delivery in their own first pregnancies compared with men and women who had been cephalic presentations (odds ratios 2.2, 95% confidence interval 1.8 to 2.7, and 2.2, 1.9 to 2.5, for men and women, respectively). The strongest risks of recurrence were found for vaginally delivered offspring and were equally strong for men and women. Increased risk of recurrence of breech delivery in offspring was present only for parents delivered at term.

CONCLUSION

Intergenerational recurrence risk of breech delivery in offspring was equally high when transmitted through fathers and mothers. It seems reasonable to attribute the observed pattern of familial predisposition to term breech delivery to genetic inheritance, predominantly through the fetus.

Prenatal exposure to wood fuel smoke and low birth weight

BACKGROUND

Maternal exposure to wood fuel smoke may lead to impaired fetal growth due to hypoxia and or oxidative stress from smoke constituents such as carbon monoxide and particulate matter.

OBJECTIVES

We studied the risk of low birth weight (LBW) and reduced mean birth weight in relation to reported use of wood for cooking during the prenatal period, compared with natural gas (NG).

METHODS

We studied a historical cohort of women who had a singleton live birth in the years 2000-2002, from a semirural area of Pakistan. Infant's birth weight was obtained from records, and prenatal records had data for maternal body mass index and parity. Cooking habits, daytime sleep habits, and type of fuel used during the pregnancies in 2000-2002 were ascertained by a survey done in 2004-2005. We performed multiple linear and logistic regression modeling using propensity scores to adjust for confounding variables.

RESULTS

Unadjusted mean (+/- SD) birth weight was 2.78 +/- 0.45 kg in wood users, and 2.84 +/- 0.43 kg (p < 0.06) in NG users. Infants born to wood users averaged 82 g lighter than infants born to NG users when weight was adjusted for confounders (p < 0.07). The rate of LBW (< 2,500 g) was 22.7% among wood users compared with 15.0% in NG users (p < 0.01), for an adjusted relative risk of 1.64 (95% confidence interval, 1.10-2.34). The population attributable risk for LBW explained by wood use was estimated to be 24%.

CONCLUSION

Cooking with wood fuel during pregnancy, a potentially modifiable exposure, was associated with LBW and marginally lower mean birth weight compared with using NG.

Women's preconceptional health and use of health services: implications for preconception care

OBJECTIVE

To improve understanding of women's use of health care before pregnancy, by analyzing how the health status and health risks of pre- and interconceptional women are associated with health services use.

DATA SOURCE

Data are from a cross-sectional random-digit dial telephone survey of a representative sample of 2002 women ages 18-45 years from the Central Pennsylvania Women's Health Study (CePAWHS). A subsample of 1,325 respondents with current reproductive capacity, classified by reproductive life stage (preconceptional or interconceptional), was analyzed.

STUDY DESIGN

Bivariate and multiple logistic regression analyses were conducted to determine how health needs (including indices of health status and health risks related to adverse pregnancy outcomes) are associated with five indicators of health services use (receipt of a regular physical exam, obstetrician-gynecologist [ob/gyn] visit, receipt of a set of recommended screening services, receipt of health counseling services on general health topics, and receipt of pregnancy-related counseling), controlling for predisposing and enabling variables.

PRINCIPAL FINDINGS

Only half of women at risk of pregnancy report receiving counseling about pregnancy planning in the past year. One-third of women surveyed did not receive routine physical examinations and screening services, and over half received little or no health counseling. Multivariate analyses showed that all the measures of health needs except for negative health behavior were related to some type of health services use. Psychosocial stress was associated with having a recent ob/gyn visit, with receiving general health counseling, and with receiving pregnancy planning counseling. Cardiovascular risk was positively associated with receiving general health counseling and a regular physical exam, but negatively associated with seeing an ob/gyn. Positive health behaviors were associated with receiving screening services and with receiving general health counseling. Preconceptional reproductive life stage was positively associated with receiving a regular physical exam and negatively associated with having an ob/gyn visit.

CONCLUSIONS

Pre- and interconceptional women with specific health care needs may not receive appropriate health care before pregnancy. Improving pregnancy experiences and outcomes requires more comprehensive preconception health care and more preventive care before the first pregnancy.

Hostility and anomie: links to preterm delivery subtypes and ambulatory blood pressure at mid-pregnancy

Underlying maternal vascular disease has been implicated as one of several pathways contributing to preterm delivery (PTD) and psychosocial factors such as hostility, anomie, effortful coping, and mastery may be associated with PTD by affecting maternal vascular health. Using data from the Pregnancy Outcomes and Community Health (POUCH) study, we included 2018 non-Hispanic White and 743 African American women from 52 clinics in five Michigan, USA communities. Women were interviewed at 15-27 weeks' gestation and followed to delivery. We found that relations between psychosocial factors and PTD subtypes (i.e. medically indicated, premature rupture of membranes, spontaneous labor) varied by race/ethnicity and socio-economic position (Medicaid insurance status). Among African American women not insured by Medicaid, anomie levels in mid-pregnancy were positively associated with medically indicated PTD after adjusting for maternal age and education. Among all women not insured by Medicaid, hostility levels were positively associated with spontaneous PTD after adjusting for maternal race/ethnicity, age, and education. Failure to detect links between psychosocial factors and PTD risk in poorer women may be due to their excess risk in multiple PTD pathways and/or a more complex web of contributing risk factors. In a subset of 395 women monitored for blood pressure, anomie scores were positively associated with systolic blood pressure and heart rate and hostility scores were positively associated with systolic and diastolic blood pressure, heart rate and mean arterial pressure in models that included time, awake/asleep, race/ethnicity, and age as covariates. Further adjustment for body mass index and smoking attenuated the anomie-vascular relations but had little effect on the hostility-vascular relations. Overall this study of pregnant women provides some physiologic evidence to support findings linking levels of anomie and hostility with risk of PTD.

Estimation of a structural model of the determinants of neonatal mortality in Hungary, 1984-88 and 1994-98

We developed and evaluated a structural model of the determinants of neonatal mortality in Hungary that embodies the causal mechanisms by which its proximate and indirect determinants--socio-economic, behavioural, and biological--are related. The statistical model used distinguishes between endogenous and exogenous variables and allows the causal effect of each to be correctly estimated. Unobserved variables are integrated into the model, which was tested using Hungarian data for the periods 1984-88 and 1994-98. The principal findings are as follows: weight at birth and duration of gestation are the most important of the (direct) causal determinants of neonatal mortality. Mother's age has an indirect and detrimental effect: when mothers are older than 30 years of age, the risk of lower birth weight or multiple births and, in consequence, neonatal mortality is increased. Father's age has no direct or indirect causal effect on neonatal mortality.

Antioxidants for preventing pre-eclampsia

BACKGROUND

Oxidative stress has been proposed as a key factor involved in the development of pre-eclampsia. Supplementing women with antioxidants during pregnancy may help to counteract oxidative stress and thereby prevent or delay the onset of pre-eclampsia.

OBJECTIVES

To determine the effectiveness and safety of any antioxidant supplementation during pregnancy and the risk of developing pre-eclampsia and its related complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 3), MEDLINE (1950 to October 2007) and Current Contents (1998 to August 2004).

SELECTION CRITERIA

All randomised trials comparing one or more antioxidants with either placebo or no antioxidants during pregnancy for the prevention of pre-eclampsia, and trials comparing one or more antioxidants with another, or with other interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality and extracted data.

MAIN RESULTS

Ten trials, involving 6533 women, were included in this review, five trials were rated high quality. For the majority of trials, the antioxidant assessed was combined vitamin C and E therapy. There was no significant difference between antioxidant and control groups for the relative risk (RR) of pre-eclampsia (RR 0.73, 95% confidence intervals (CI) 0.51 to 1.06; nine trials, 5446 women) or any other primary outcome: severe pre-eclampsia (RR 1.25, 95% CI 0.89 to 1.76; two trials, 2495 women), preterm birth (before 37 weeks) (RR 1.10, 95% CI 0.99 to 1.22; five trials, 5198 women), small-for-gestational-age infants (RR 0.83, 95% CI 0.62 to 1.11; five trials, 5271 babies) or any baby death (RR 1.12, 95% CI 0.81 to 1.53; four trials, 5144 babies). Women allocated antioxidants were more likely to self-report abdominal pain late in pregnancy (RR 1.61, 95% CI 1.11 to 2.34; one trial, 1745 women), require antihypertensive therapy (RR 1.77, 95% CI 1.22 to 2.57; two trials, 4272 women) and require an antenatal hospital admission for hypertension (RR 1.54, 95% CI 1.00 to 2.39; one trial, 1877 women). However, for the latter two outcomes, this was not clearly reflected in an increase in any other hypertensive complications.

AUTHORS' CONCLUSIONS

Evidence from this review does not support routine antioxidant supplementation during pregnancy to reduce the risk of pre-eclampsia and other serious complications in pregnancy.

Social inequalities in preterm birth in Scotland 1980-2003: findings from an area-based measure of deprivation

OBJECTIVE

The preterm birth rate in Scotland has been increasing in recent years. Although preterm birth rates show a social gradient, it is unclear how this gradient has been affected by the overall increase. We examined time trends in singleton live preterm birth rates in relation to area-based socio-economic indicators.

DESIGN

Population-based retrospective cohort study.

SETTING

Scotland.

PARTICIPANTS

All singleton live births delivered in Scottish hospitals between 1980 and 2003 (n= 1 423 993).

MAIN OUTCOME MEASURES

Singleton live preterm birth rates in each deprivation quintile were derived. Subgroup analyses of those born moderately preterm (32-36 weeks), very preterm (28-31 weeks) and extremely preterm (24-27 weeks) were performed.

RESULTS

The rate of singleton live preterm births increased from 49.7 per 1000 live births in the 5-year period 1980-84 to 56.1 per 1000 in the 4-year period 2000-03, a relative increase of 12.9%. A marked social gradient was apparent at all time periods: relative indices of inequality were 1.63 (95% CI 1.38-1.92) in 1980-84 and 1.55 (1.44-1.66) in 2000-03. Similar social gradients existed for all gestational age subgroups. Smoking status at first antenatal contact and increased obstetric intervention, possibly reflecting improvements in fetal monitoring and neonatal care, appeared to explain some but not all the social gradient.

CONCLUSIONS

Social inequalities in preterm birth were apparent in Scotland between 1980 and 2003. In addition to helping pregnant women to stop smoking, other means to reduce social inequalities are required.

Social inequalities in use of prenatal care in Manitoba

OBJECTIVE

Analysis of regional variations in use of prenatal care to identify individual-level and neighbourhood-level determinants of inadequate prenatal care among women giving birth in the province of Manitoba.

METHODS

Data were obtained from Manitoba Health administrative databases and the 1996 Canadian Census. An index of prenatal care use was calculated for each singleton live birth from 1991 to 2000 (N = 149,291). Births were geocoded into 498 geographic districts, and a spatial analysis was conducted, consisting of data visualization, spatial clustering, and data modelling using Poisson regression.

RESULTS

We found wide variation in rates of inadequate prenatal care across geographic areas, ranging from 1.1% to 21.5%. Higher rates of inadequate care were found in the inner-city of Winnipeg and in northern Manitoba. After adjusting for individual characteristics, the highest rates of inadequate prenatal care were among women living in neighbourhoods with the lowest average family income, the highest proportion of the population who were unemployed, the highest rates of recent immigrants, the highest percentage of the population reporting Aboriginal status, the highest percentage of single parent families, the highest percentage of the population with fewer than nine years of education, and the highest rates of women who smoked during pregnancy.

CONCLUSION

Social inequalities exist in the use of prenatal care among Manitoba women, despite there being a universally funded health care system. Regional disparities in rates of inadequate prenatal care emphasize the need for further research to determine specific risk factors for inadequate prenatal care in socioeconomically disadvantaged neighbourhoods, followed by provision of effective targeted services.

Socioeconomic status and lung function

Poverty is a major social problem in the United States and throughout much of the world. Poverty and the broader term socioeconomic status (SES) are important determinants of overall health status and many pulmonary diseases. The purpose of this study was to review the medical literature from the past 20 years addressing the relationship between SES and lung function in both children and adults. There is a significant negative correlation between lung function (primarily FEV1 and FVC) and SES. This relationship exists even after adjusting for smoking status, occupational exposures, and race. The magnitude of the effect of low SES on lung function is variable, but FEV1 reductions of >300 mL in men and >200 mL in women have been reported. SES is an important determinant of lung function and an underrecognized contributor to pulmonary disease.

I, Novaes HMD, Siqueira AAFD, Campbell O, Rodrigues LC. Fatores de risco para mortalidade neonatal precoce

OBJETIVO: Avaliar os fatores de risco da mortalidade neonatal precoce. MÉTODOS: Estudo caso-controle de base populacional com 146 óbitos neonatais precoces e amostra de 313 controles obtidos entre os sobreviventes ao período neonatal, na região sul do município de São Paulo, no período de 1/8/2000 a 31/1/2001. As informações foram obtidas por meio de entrevistas domiciliares e prontuários hospitalares. Foi realizada análise hierarquizada em cinco blocos com características: 1) socioeconômicas das famílias e das mães; 2) psicossociais maternas; 3) biológicas e da história reprodutiva materna; 4) do parto; 5) do recém-nascido. RESULTADOS: Os fatores de risco para a mortalidade neonatal precoce foram: Bloco 1: baixa escolaridade do chefe da família (OR=1,6; IC 95%: 1,1;2,6); domicílio em favela (OR=2,0; IC 95%: 1,2;3,5), com até um cômodo (OR=2,2; IC 95%: 1,1;4,2); Bloco 2: mães com união recente (OR=2,0; IC 95%: 1,0;4,2) e sem companheiro (OR=1,8; IC 95%: 1,1;3,0), presença de maus tratos (OR=2,7;1,1-6,5); Bloco 3: presença de intercorrência na gravidez (OR=8,2; IC 95%: 5,0;13,5), nascimento prévio de baixo peso (OR=2,4; IC 95%: 1,2;4,5); pré-natal ausente (OR=16,1; IC 95%: 4,7;55,4) ou inadequado (OR=2,1; IC 95%: 2,0;3,5); Bloco 4: presença de problemas no parto (OR=2,9; IC 95%: 1,4;5,1), mães que foram ao hospital de ambulância (OR=3,8; IC 95%: 1,4;10,7); Bloco 5: baixo peso ao nascer (OR=17,3; IC 95%: 8,4;35,6), nascimento de pré-termo (OR=8,8; IC 95%: 4,3;17,8). CONCLUSÕES: Além dos fatores proximais (baixo peso ao nascer, gestações de pré-termo, problemas no parto e intercorrências durante a gestação), identificou-se a participação de variáveis que refletem exclusão social e de fatores psicossociais. Esse contexto pode afetar o desenvolvimento da gestação e dificultar o acesso das mulheres aos serviços de saúde. A assistência pré-natal adequada poderia minimizar parte do efeito dessas variáveis.

Are intrauterine growth restriction and preterm birth associated with dental caries?

OBJECTIVES

To assess the association between two intrauterine growth restriction (IUGR) surrogates - IUGR [small for gestational age birth (SGA) and fetal growth restriction (FGR)] and preterm birth with dental caries.

METHODS

Data from the Third National Health and Nutritional Examination Survey (1988-1994) were used, including 2- to 5.9-year-old singletons (n = 3189). Dental caries was defined as presence of any teeth with dental caries (treated or untreated) and also as presence of at least two teeth with dental caries. Exposure variables were preterm birth (<37 gestational weeks), FGR, and SGA. Covariates included were poverty, race/ethnicity, age, sex, sucrose intake, environmental tobacco smoking, dental visits, education of head of household, breastfeeding, and use of baby bottle. Separate statistical analyses were conducted for IUGR and for preterm birth through the estimation of prevalence ratio (PR), taking complex sampling design into consideration and adjusting for confounders. Sensitivity analysis was conducted including and excluding 2-year-old children and also with the two definitions of dental caries.

RESULTS

In general, the inclusion of 2-year-old children and the case definition of presence of any teeth with dental caries biased the results toward the null, but with no major changes in the results. In bivariate analysis, SGA and FGR birth were both negatively but not significantly associated with dental caries while a significant positive association was found for preterm birth. Sensitivity analysis showed that the PR for preterm in bivariate analysis varied from 1.65 (95% CI 1.14-2.40) to 1.84 (95% CI 1.19-2.83). After adjusting for confounders, the PR for preterm birth varied from 1.38 (95% CI 1.00-1.89) to 1.64 (95% CI 1.22-2.20). After adjustment, the PR for SGA varied from 0.79 (95% CI 0.56-101) to 0.66 (95% CI 0.33-0.96). For children from 3 to 5.9 years old, the adjusted PR for FGR using the category 'none' as reference were mild (PR 1.10; 95% CI 0.76-1.58), moderate (PR 0.66; 95% CI 0.26-167), and severe (PR 0.59; 95% CI 0.36-0.99). These values for FGR were very similar for the other models using other classifications of case definition or inclusion of 2-year-old children.

CONCLUSIONS

Preterm birth was found to be positively associated with dental caries while there is an indication that SGA and FGR are negatively associated with dental caries. Although the negative association is counterintuitive, it is possible that increased antibiotic use and delayed tooth eruption may explain the negative association between IUGR and dental caries.

Pregnancy outcome in primiparae of advanced maternal age

OBJECTIVE

To investigate the impact of maternal age on singleton pregnancy outcome, taking into account intermediate and confounding factors.

STUDY DESIGN

In this population-based retrospective cohort study, perinatal data of primiparous women aged 35 years or more (n = 2970), giving birth to a singleton child of at least 500 g, were compared to data of primiparous women aged 25-29 years old (n = 23,921). Univariate analysis was used to assess the effect of maternal age on pregnancy outcomes. The effects of intermediate (hypertension, diabetes and assisted conception) and confounding factors (level of education) were assessed through multivariable logistic regression analysis.

RESULTS

Older maternal age correlated, independently of confounding and intermediate factors, with very preterm birth (gestational age <32 weeks) [adjusted odds ratio (AOR) 1.51, 95% confidence intervals (CI) 1.04-2.19], low birth weight (birth weight <2500 g) (AOR 1.69, 95% CI 1.47-1.94) and perinatal death (AOR 1.68, 95% CI 1.06-2.65).

CONCLUSION

Maternal age is an important and independent risk factor for adverse pregnancy outcome.

Explaining differences in birthweight between ethnic populations. The Generation R Study

OBJECTIVE

To examine whether differences in birthweight of various ethnic groups residing in The Netherlands can be explained by determinants of birthweight.

DESIGN

Population-based birth cohort study.

SETTING

Data of pregnant women and their partners in Rotterdam, The Netherlands.

POPULATION

We examined data of 6044 pregnant women with a Dutch, Moroccan, Turkish, Capeverdean, Antillean, Surinamese-Creole, Surinamese-Hindustani and Surinamese-other ethnic background.

METHODS

Regression analyses were used to assess the impact of biomedical, socio-demographic and lifestyle-related determinants on birthweight differences.

MAIN OUTCOME MEASURE

Birthweight was established immediately after delivery in grams.

RESULTS

Compared with mean birthweight of offspring of Dutch women (3485 g, SD 555), the mean birthweight was lower in all non-Dutch populations, except in Moroccans. Differences ranged from an 88-g lower birthweight in offspring of the Turkish women to a 424-g lower birthweight in offspring of Surinamese-Hindustani women. Differences in gestational age, maternal and paternal height largely explained the lower birthweight in the Turkish, Antillean, Surinamese-Creole and Surinamese-other populations. Differences in birthweight between the Dutch and the Capeverdean and Surinamese-Hindustani populations could only partly be explained by the studied determinants.

CONCLUSIONS

These results confirm significant differences in birthweight between ethnic populations that can only partly be understood from established determinants of birthweight. The part that is understood points to the importance of determinants that cannot easily be modified, such as parental height. Further study is necessary to obtain a fuller understanding.

Are there differences in birth weight between neighbourhoods in a Nordic welfare state?

Background

The objective of this cohort study was to examine the effect on birth weight of living in a disadvantaged neighbourhood in a Nordic welfare state. Birth weight is a health indicator known to be sensitive to political and welfare state conditions. No former studies on urban neighbourhood differences regarding mean birth weight have been carried out in a Nordic country.

Methods

A register based on individual data on children's birth weight and maternal risk factors was used. A neighbourhood characteristic, i.e. an aggregated measure on income was also included. Connections between individual- and neighbourhood-level determinants and the outcome were analysed using multi-level regression technique. The study covered six hundred and ninety-six neighbourhoods in the three major cities of Sweden, Stockholm, Göteborg and Malmö, during 1992–2001. The majority of neighbourhoods had a population of 4 000–10 000 inhabitants. An average of 500 births per neighbourhood were analysed in this study.

Results

Differences in mean birth weight in Swedish urban neighbourhoods were minor. However, gestational length, parity and maternal smoking acted as modifiers of the neighbourhood effects. Most of the observed variation in mean birth weight was explained by individual risk factors.

Conclusion

Welfare institutions and benefits in Sweden might buffer against negative infant outcomes due to adverse structural organisation of urban neighbourhoods.

Maternal smoking, social class and outcomes of pregnancy

Exposure to tobacco during pregnancy is an important risk factor for infant health. Recently the prevalence of smoking during pregnancy has declined in our area. The objective of this study was to analyse the association between several social variables and the fetal exposure to smoking, as well as the association between maternal smoking and some adverse gestational outcomes. Data collection was cross-sectional. The study population were women in the city of Barcelona (Catalonia, Spain) delivering a child without birth defects. The sample corresponded to the controls of the Birth Defects Registry of Barcelona, 2% of all pregnancy deliveries in the city from 1994 to 2003 (n = 2297). Information sources were hospital records and a personal interview of mothers. The analysis measured first the association between independent variables (instruction level, social class, occupation, nationality, planned pregnancy, parity, hospital funding and smoking status of the mother's partner) with two dependent variables: smoking at the initiation of pregnancy and quitting during pregnancy. Second, the persistence of smoking over pregnancy and all independent variables were studied with three variables indicating adverse outcomes of pregnancy: low gestation, low birthweight and intrauterine growth restriction (IUGR). Finally, the joint association between the persistence of smoking over pregnancy and social class taken as independent variables was determined with the three variables indicating adverse outcomes of pregnancy. Logistic regression models were fitted, adjusting for maternal age. Results are presented as odds ratios with their 95% confidence intervals. The prevalence of smoking at the onset of gestation was 41%, and 40% of these women quit during pregnancy, so that 25% delivered as active smokers. Fewer women with higher educational levels and from families with non-manual jobs smoked, as did immigrants, those planning pregnancy and women whose partner did not smoke. Smoking immigrants quit more frequently than nationals, as did those planning pregnancy, primiparae, and women whose partner did not smoke. Low gestation, low birthweight and IUGR were more frequent among smokers and women with a manual occupation, but manual occupation lost its significance when adjusting for smoking. The association between smoking and adverse results was higher for IUGR. In conclusion, the prevalence of smoking and quitting during pregnancy varied according to social factors. The influence of social factors on the outcome of pregnancy was mediated strongly by smoking in a country that provides access to health care free of cost. A priority in reducing inequalities in health is to help women from manual work backgrounds quit smoking.

Effect of smoking and alcohol use during pregnancy on the occurrence of low birthweight in a farming region in South Africa

The aim of this case-control study was to determine the risk factors for low birthweight in a farming region in South Africa, with particular attention to maternal alcohol use and smoking, both independently and in combination. Data collection was via structured postpartum interviews and review of antenatal and delivery records. The study setting was a regional referral hospital in a farming region. The study subjects were 200 infants with birthweight < 2500 g (cases) and 200 unmatched control infants of normal weight born during the same period as the cases. The outcome measure was low birthweight, i.e. infant birthweight <2500 g. Results showed the contribution of term low birthweight (as a measure of intrauterine growth retardation) to the total low-birthweight incidence was almost 50%, indicating a substantial intrauterine growth retardation component in this population. Sociodemographic factors were not as predictive of low birthweight in this predominantly low income population. Smoking (adjusted OR 2.67, [95% CI 1.69, 4.20]) was the strongest life style-related predictor of low birthweight. The alcohol low-birthweight relationship was not significant when adjusted for smoking status (crude OR 2.15, [95% CI 1.37, 3.39]; adjusted OR 1.32, [95% CI 0.80, 2.20]). However, there appeared to be an interaction with combined use of these two substances during pregnancy that increased the risk of low birthweight (adjusted OR increased to 4.24, [95% CI 1.01, 17.76]. It is clear that life style factors such as smoking and drinking are contributing to the occurrence of low birthweight in the target region. A comprehensive health promotion programme needs to be implemented as an integral part of antenatal and family planning services, to reduce smoking and drinking by women in this community.

Early childhood origins of the income/health gradient: The role of maternal health behaviors

Several recent studies in the US, Canada, and the UK have demonstrated a positive relationship between family income and child health, though the mechanisms underlying this relationship are poorly understood. Using data from the 1988 US National Maternal and Infant Health Survey and the 1991 follow-up, this paper tests whether maternal health status and health behaviors during pregnancy and early infancy can explain the relationship between family income and subjective health status at age 3. We find that, while a detailed set of controls for health risk factors including maternal smoking, drinking, and vitamin use during pregnancy, as well as breastfeeding and secondhand smoke exposure after birth, are significantly related to family income and maternal education, they do not explain the relationship between family income and maternal-assessed health of the child. We suggest that these results point to either more salient pathways through which family income impacts child health, such as maternal stress, or to the possibility that differences in subjective health status do not correspond to differences in objective health status in the same way for higher- and lower-income respondents.

Intrauterine growth standards in a developing country: a study of singleton livebirths at 28-42 weeks' gestation

This study aimed to develop fetal growth charts for the population of Greater Beirut, Lebanon, and compare them with previously established references. A survey of consecutive singleton livebirths admitted to normal nurseries and neonatal intensive care units of major hospitals, through the database project of the National Collaborative Perinatal Neonatal Network was used as a design. The study was conducted in nine major healthcare institutions serving the population of Beirut and its suburbs. A total of 24 767 singleton livebirths delivered between 28 and 42 weeks' gestation, with known data on gender, gestational age and anthropometric characteristics were recorded between 1 April 1999 and 31 March 2002. Growth charts were developed by plotting birthweight, length and head circumference percentiles against gestational age for male and female infants separately. Overall, 1348 (5.4%) pregnancies were delivered before 37 weeks' gestation and 1227 (4.9%) were low birthweight. Male infants were delivered slightly earlier than their female counterparts and the mean birthweight, length and head circumference were consistently higher in males. A total of 2247 (9.1%) infants were small-for-gestational-age, with a male-to-female sex ratio of 1.03. Using previously established growth references that overestimated small-for-gestational-age prevalence resulted in a greater proportion of false positives. The opposite was true for growth references that underestimated small-for-gestational-age prevalence. The current growth charts present useful tools for assessing the general health status of newborn infants delivered at sea level in the urban areas of Lebanon and other East Mediterranean countries.

Maternal Work and Birth Outcome Disparities

OBJECTIVES

We tested relations between aspects of maternal work and birth outcomes in a national sample and in subgroups known to experience disparities.

METHODS

Three indices of work attributes (Status and Recognition, Physical Demands, and Exposure to Conflict) were derived by factor analysis of variables extracted from the Department of Labor's O*Net database. The indices were linked to the National Longitudinal Survey of Youth using occupation codes for the primary jobs held by women who gave birth between 1979 and 2000 and worked during the quarter prior to birth (n = 3,386 births to n = 2,508 mothers). Multiple regression was used to model birth outcomes as functions of the work attribute indices, controlling for several measures of socioeconomic status and risk factors for adverse birth outcomes.

RESULTS

In the full sample, work-related Physical Demands were associated with lower average birthweight and increased odds of preterm birth while Status and Recognition was associated with higher average birthweight and lower odds of fetal growth restriction. In stratified models, Status and Recognition was associated with higher birth weight among women with low (versus high) income and with lower odds of preterm birth among women with low (versus high) education. Physical Demands were associated with higher rates of preterm birth among women with low (versus high) income and education and among African-American mothers (compared to Whites).

CONCLUSIONS

The work environment is an important predictor of healthy births. Relations between maternal work attributes and birth outcomes differ by race/ethnicity and socioeconomic status and according to the outcome under investigation. Further research with measures of work attributes specific to maternal work experiences is recommended to confirm our findings.

Social inequality and perinatal health: comparison of three Brazilian cohorts

The objective of the present study was to estimate and compare social inequality in terms of three indicators, i.e., low birth weight (LBW), preterm birth (PTB) and small for gestational age (SGA) birth, in three birth cohorts. Two cohorts were from the city of Ribeirão Preto, where data were collected for all 6748 live born singletons in 1978/79 and for one third of live born singletons (2846) in 1994. The third cohort consisted of 2443 singletons born in São Luís over a period of one year (1997/98). In Ribeirão Preto, LBW and PTB rates increased in all social strata from 1978/79 to 1994. Social inequalities regarding LBW and PTB disappeared since the increase in these rates was more accelerated in the groups with higher educational level. The percentage of SGA infants increased over the study period. Social inequality regarding SGA birth increased due to a more intense increase in SGA births in the strata with lower schooling. In São Luís, in 1997/98 there was no social inequality in LBW or PTB rates, whereas SGA birth rate was higher in mothers with less schooling. We speculate that the more accelerated increase in medical intervention, especially due to the increase in cesarean sections in the more privileged groups, could be the main factor explaining the unexpected increase in LBW and PTB rates in Ribeirão Preto and the decrease or disappearance of social inequality regarding these perinatal indicators in the two cities.

Social and early-life determinants of overweight and obesity in 18-year-old Swedish men

OBJECTIVES

To investigate the combined effects of size at birth and maternal education on prevalence of overweight and obesity among 18-year-old men.

METHODS

We studied the associations of weight for gestational age and maternal education with body mass index (BMI), overweight and obesity by multivariate linear and logistic regression, adjusted for mother's age, parity and diabetes in a register-based cohort of 6535 men born between 1973 and 1985. Further adjustments for mother's height, pre-pregnancy weight, weight gain and smoking during pregnancy were made in a subsample of 1103 men born between 1982 and 1985.

RESULTS

Mean BMI and prevalence of overweight and obesity decreased with higher maternal education. Mother's BMI and smoking were the strongest predictors of sons' overweight and obesity and essentially accounted for the variation in son's overweight by maternal education. The association of size at birth with later overweight was present only in sons born to mothers who were nonsmokers (odds ratio per 1 standard deviation weight for gestational age z-score 1.46, 95% CI 1.18-1.81) and became substantially reduced on adjustment for mother's pre-pregnancy BMI. Length of gestation was not statistically significantly associated with BMI at age 18.

CONCLUSIONS

Maternal overweight and maternal smoking were the strongest determinants of offspring overweight and its social patterning, and should be a priority for public health policies.

Standards for the measurement of birth weight, length and head circumference at term in neonates of European, Chinese and South Asian ancestry

BACKGROUND

Fetal growth restriction is associated with metabolic derangements in the newborn, impaired functioning in childhood and chronic diseases in adulthood. Differences between ethnic groups with respect to fetal growth may result in the misclassification of constitutionally small or large babies as having abnormal growth for their gestational age. We have developed intrauterine growth charts based on precise measurements of newborns whose parents were both of European, Chinese or South Asian ethnicity.

METHODS

Weight, length and head circumference were measured in 2695 infants born to healthy non-smoking mothers in British Columbia at 37-41 completed weeks of gestation. Gestational age was confirmed by ultrasound before 20 weeks of gestation. Weight was measured by digital scale, length by stadiometer and head circumference by firm plastic tape measures. Means and 95% confidence intervals were compared among newborns grouped by ethnicity and sex. Smoothed graphs were constructed for visual interpretation.

RESULTS

At 40 weeks, infants of European descent ("European" infants) weighed 225.5 g more on average than infants of Chinese descent ("Chinese" infants) (p < 0.001) and 254.6 g more than infants of South Asian descent ("South Asian" infants) (p < 0.001). The mean difference in birth weight between Chinese and South Asian infants (19.1 g) was not statistically significant. The mean length of European infants at 40 weeks of gestation was 0.89 cm greater than that of Chinese infants (p < 0.001). Differences in mean length between European and South Asian babies or between Chinese and South Asian babies was not statistically significant. The mean head circumferance of European babies was 0.50 cm larger than that of Chinese babies at 40 weeks (p < 0.001) but did not differ significantly from that of South Asian babies. South Asian and Chinese babies had similar mean head circumferences at 40 weeks. When differences in mean birth weight, length and head circumference were examined within boys and girls, the observed differences according to ethnicity remained statistically significant.

CONCLUSION

Important differences in weight, length and head circumferences are reported among babies according to ethnicity. The use of sex- and ethnicity-specific growth charts may prevent the misclassification of newborns as small or large for gestational age.

Population attributable risk for adverse pregnancy outcomes related to smoking in adolescents and adults

BACKGROUND

Little is known about how population-attributable risks (PAR) for adverse birth outcomes due to smoking differ in adolescent and adult pregnancies.

METHODS

An analysis of community and hospital-based cross-sectional studies in Liverpool was undertaken to estimate the PAR values of low birthweight (LBW), preterm birth, and small for gestational age (SGA) births resulting from pregnancy smoking covering the period between 1983 and 2003. Maternal smoking status and pregnancy outcomes were available for a sample of 12631 women.

RESULTS

The prevalence of maternal pregnancy smoking was 40% in the community sample and 33% in adults and 40% among adolescent pregnancies in the hospital sample. The PAR values (95% CI) associated with LBW, preterm birth and SGA outcomes due to maternal pregnancy smoking in the community sample were 27% (25-30), 13% (11-15) and 25% (23-27), respectively. The PAR values in adults in the hospital sample were 29% (27-31) for LBW, 16% (14-19) for preterm birth and 28% (26-31) for SGA. The corresponding PAR values in adolescents were 39% (34-43), 12% (7-18) and 31% (23-40). The LBW risk attributed to pregnancy smoking in adolescents was significantly higher than for adults (P=0.05).

CONCLUSION

About one-third of LBW, one-quarter of SGA and one-sixth of preterm births could be attributed to maternal smoking during pregnancy. The magnitude of the problem was greater among adolescent pregnancies, among whom a sub-group of mothers with very high risk for adverse birth outcomes due to pregnancy smoking was identified.

The neighbourhood they live in: does it matter to women's smoking habits during pregnancy?

Socioeconomic factors in the neighbourhood are associated with smoking habits in various populations. We studied a 10-year cohort to determine whether women's smoking behaviour during pregnancy can similarly be determined by neighbourhood economic and ethnic factors. The cohort included 127,074 primiparous pregnant women in 592 Swedish neighbourhoods during the years 1992-2001. Multilevel technique was used to regress pregnancy smoking on socioeconomic individual-level variables and neighbourhood characteristics. Seven percent of the variation in pregnancy smoking was at the neighbourhood level and the odds of smoking during pregnancy were doubled in poorer areas. Health education and smoking cessation interventions should be directed at maternity care units in deprived neighbourhoods.

Reproductive characteristics of Southeast Asian immigrants before and after migration

We describe the reproductive health and practices of Hmong immigrants before and after migration to the United States. Data were gathered as part of an ongoing study on the impact of perinatal exposure to environmental chemicals on children's health in Hmong residents of Green Bay, Wisconsin between August 1999 and May 2002. Of the 742 pregnancies reported by 141 reproductive-aged couples, 669 were live births. The Hmong have an average of 5.2 children (range 0-14) and the sex ratio differed by country of birth. Prenatal care began in the first trimester for 60% of US-born infants, up from 12% prior to immigration. Breastfeeding decreased from 94% and 88% in Laos and Thailand to only 11% for Hmong born in the US. Contraceptive use was reported by 25.5% of women; few reported smoking and alcohol consumption. The results suggest that Hmong immigrants may benefit from public health support targeting prenatal care and breastfeeding practices.

The implications of maternal overweight and obesity on the course of pregnancy and birth outcomes

The increasing prevalence of overweight and obesity among women of childbearing age is a growing public health concern in the United States. The average body mass index (BMI) is increasing among all age categories and women enter pregnancy at higher weights. Women are also more likely to retain gestational weight with each pregnancy. Women who are overweight (BMI 25–30) and obese (BMI ≥30) are at greater risk of adverse reproductive health outcomes compared to women of normal weight status (BMI 19.8–25). This article provides an overview of the complications associated with maternal overweight and obesity including diabetes, pre-eclampsia, c-sections, and birth defects. We present updated information on the weight trends among women. Finally, we present an overview of the prevention studies aimed at adolescents and women prior to pregnancy.

Individual and community predictors of preterm birth and low birthweight along the rural-urban continuum in central Pennsylvania

CONTEXT

Preterm birth and low birthweight remain high priority public health problems and are associated with increased risk of infant mortality as well as long-term health impairments. Although 20% of all births nationally are to rural women, relatively little attention has been paid to pregnancy outcomes in rural areas relative to more urbanized areas.

PURPOSE

This study examines the relationship of individual- and community-level socioeconomic, health care, and health status-related characteristics to preterm birth and low birthweight outcomes among women living in urban and various types of rural communities.

METHODS

Vital record data on singleton first births to residents of a 28-county region in central Pennsylvania in 2002 (N = 11,546) were merged with zip code-level information from the census and residence in a primary care health professional shortage area. Rural-urban commuting area codes were also appended. Multiple logistic regression analyses were performed to model risks of preterm birth and low birthweight using generalized estimating equations to account for clustering within zip code.

FINDINGS

Women residing in large rural city-focused areas had lower adjusted odds of both preterm birth and low birthweight as compared to urban women, controlling for individual risk factors including maternal demographic characteristics, health conditions, and prenatal care use. In contrast, risks of these adverse birth outcomes were not significantly lower among women living in more rural areas relative to those in urban communities.

CONCLUSIONS

Reduced risks of preterm birth and low birthweight risk are associated with some, but not all types of rural as compared to urban communities.

Avoidable mortality by neighbourhood income in Canada: 25 years after the establishment of universal health insurance

AIM

To examine neighbourhood income differences in deaths amenable to medical care and public health over a 25-year period after the establishment of universal insurance for doctors and hospital services in Canada.

METHODS

Data for census metropolitan areas were obtained from the Canadian Mortality Database and population censuses for the years 1971, 1986, 1991 and 1996. Deaths amenable to medical care, amenable to public health, from ischaemic heart disease and from other causes were considered. Data on deaths were grouped into neighbourhood income quintiles on the basis of the census tract percentage of population below Canada's low-income cut-offs.

RESULTS

From 1971 to 1996, differences between the richest and poorest quintiles in age-standardised expected years of life lost amenable to medical care decreased 60% (p<0.001) in men and 78% (p<0.001) in women, those amenable to public health increased 0.7% (p = 0.94) in men and 20% (p = 0.55) in women, those lost from ischaemic heart disease decreased 58% in men and 38% in women, and from other causes decreased 15% in men and 9% in women. Changes in the age-standardised expected years of life lost difference for deaths amenable to medical care were significantly larger than those for deaths amenable to public health or other causes for both men and women (p<0.001).

CONCLUSIONS

Reductions in rates of deaths amenable to medical care made the largest contribution to narrowing socioeconomic mortality disparities. Continuing disparities in mortality from causes amenable to public health suggest that public health initiatives have a potentially important, but yet un-realized, role in further reducing mortality disparities in Canada.

Effects of socioeconomic status on breastfeeding duration in mothers of preterm and term infants

BACKGROUND

The propensity to breastfeed is not only of importance with regard to the beneficial effects on the individual, but is also of concern as an indicator of health behaviour related to social conditions. Thus, our aim was to investigate the impact of socioeconomic status (SES) on breastfeeding duration in mothers of preterm and term infants.

METHODS

Prospective population based cohort study. Data for infants registered in breastfeeding databases of two Swedish counties 1993-2001 were matched with data from two national registries-the Medical Birth Registry and Statistics Sweden. A total of 37,343 mothers of 2093 preterm and 35,250 term infants participated.

RESULTS

All socioeconomic factors; maternal educational level, maternal unemployment benefit, social welfare and equivalent disposable income, were strongly associated with breastfeeding when examined individually in mothers of preterm and term infants. Some of the associations attenuated when investigated simultaneously. Independently of SES and confounders, mothers of preterm infants were at higher risk of weaning before the infant was 2 months (adjusted odds ratio (OR) 1.70; 95% confidence interval ((CI) 1.46-1.99)), 4 months (OR 1.79; CI 1.60-2.01), 6 months (OR 1.48; CI 1.33-1.64), and 9 months old (OR 1.19; CI 1.06-1.34), compared with mothers of term infants.

CONCLUSIONS

In Sweden, despite its social welfare support system and a positive breastfeeding tradition, SES clearly has an impact on the breastfeeding duration. Mothers of preterm infants breastfeed for a shorter time compared with mothers of term infants, even when adjustments are made for SES and confounders.

Does the measure of economic disadvantage matter? Exploring the effect of individual and relative deprivation on intrauterine growth restriction

This paper examines the relation between health, individual income, and relative deprivation. Three alternative measures of relative deprivation are described, Yitzhaik relative deprivation, Deaton relative deprivation, and log income difference relative deprivation, with attention to problems in measuring permanent disadvantage when the underlying income distribution is changing over time. We used data from the National Longitudinal Surveys of Youth, a US-based longitudinal survey, to examine the associations between disadvantage, measured cross-sectionally and aggregated over the life course, and intrauterine growth restriction (IUGR). We reject the hypotheses that any of the economic measures, whether permanent/contemporaneous or individual/relative, have different associations with IUGR in terms of sign and significance. There was some evidence that permanent economic disadvantage was associated with greater risk of IUGR than those on the corresponding contemporaneous measures. The fitted values from logistic regressions on each measure of disadvantage were compared with the two-way plots of the observed IUGR-income pattern. Deaton relative deprivation and log income difference tracked the observed probability of IUGR as a function of income more closely than the other two measures of relative deprivation. Finally, we examined the determinants of each measure of disadvantage. Observed characteristics in childhood and adulthood explained more of the variance in log income difference and Deaton relative deprivation than in the other two measures of disadvantage. They also explained more of the variance in permanent disadvantage than in the contemporaneous counterpart.

Gestational age shortening in single births at term. Italy 1990-1998

The increasing incidence of moderate preterm births (32-36 gestation weeks) might reflect a more general tendency toward a shortening of the gestational length occurring also in the term births (37 + gestation weeks). We examined all Italian 1st live born singletons (n = 2,356,365) and found that from 1990 to 1998 the births of 40 + gestation weeks decreased from 60.7 to 51.7% and among term births the average gestation weeks decreased from 39.74 to 39.55. In term pregnancies the effect of low education and advanced age of the mother in decreasing the gestational length persisted over time, but, independently of the maternal factors, the pregnancies experienced a progressive shortening. The finding, if confirmed for other countries, should deserve further investigations on possible determinants, as improved estimates of gestational age through the widespread use of prenatal ultrasound or diffusion of hazardous and stressing working and living conditions.

Birth outcomes among urban African-American women: a multilevel analysis of the role of racial residential segregation

Residential segregation is a common aspect of the urban experiences of African-Americans in the United States (US), yet few studies have considered how segregation might influence perinatal health. Here, we develop a conceptual model of relationships between segregation and birth outcomes and test the implications of the model in a sample of 434,376 singleton births to African-American women living in 225 US Metropolitan Statistical Areas (MSAs). Data from the National Center for Health Statistics 2002 birth files were linked to data from the 2000 US Census and two distinct measures of segregation: an index of isolation (the probability that an African-American resident will encounter another African-American resident in any random neighborhood encounter) and an index of clustering (the extent to which African-Americans live in contiguous neighborhoods). Using multilevel regression models, controlling for individual- and MSA-level socioeconomic status and other covariates, we found higher isolation was associated with lower birthweight, higher rates of prematurity and higher rates of fetal growth restriction. In contrast, higher clustering was associated with more optimal outcomes. We propose that isolation reflects factors associated with segregation that are deleterious to health including poor neighborhood quality, persistent discrimination and the intra-group diffusion of harmful health behaviors. Associations with clustering may reflect factors associated with segregation that are health-promoting such as African-American political power empowerment, social support and cohesion. Declines in isolation could represent positive steps toward improving birth outcomes among African-American infants while aspects of racial contiguity appear to be mitigating or indeed beneficial. Segregation is a complex multidimensional construct with both deleterious and protective influences on birth outcomes, depending on the dimensions under consideration. Further research to understand racial/ethnic and economic health disparities could benefit from a focus on the contributory role of neighborhood attributes associated with the dimensions segregation and other social geographies.

The influence of maternal childhood and adulthood social class on the health of the infant

The aim of this study is to investigate how maternal childhood and adulthood social class contribute to social inequalities in low birth weight, neonatal mortality and postneonatal mortality. In particular I consider the combined influence of childhood and adult class, and compare outcomes with regard to the time distance from birth. Analyses were performed on a large sample of Swedish births from 1973 to 1990, restricted to infants of women with both childhood and adult class, classified as manual or non-manual. Logistic regression is used to compare odds ratios for social classes. The results indicate that manual maternal childhood class is consistently associated with higher risks for low birth weight and neonatal mortality, even when adult class was adjusted for. The influence of adult class was greater than that of childhood class for all health outcomes. Compared to higher/middle non-manual workers, unskilled workers in the service sector and workers in the manufacturing sector displayed the highest odds ratios for all adverse health outcomes. When both childhood and adult class were taken into account, social differences were greater for low birth weight and neonatal mortality than for postneonatal mortality. Maternal childhood class had more influence on low birth weight and neonatal mortality than on postneonatal mortality. I conclude that maternal childhood and adulthood social class are both independently associated with inequalities in health-related birth outcomes, and that social differences are greater for health outcomes closer to birth.

The Asian birth outcome gap

Asians are often considered a single group in epidemiological research. This study examines the extent of differences in maternal risks and birth outcomes for six Asian subgroups. Using linked birth/infant death certificate data from the State of California for the years 1992-97, we assessed maternal socio-economic risks and their effect on birthweight, preterm delivery (PTD), neonatal, post-neonatal and infant mortality for Filipino (87,120), Chinese (67,228), Vietnamese (45,237), Korean (23,431), Cambodian/Laotian (21,239) and Japanese (18,276) live singleton births. The analysis also included information about non-Hispanic whites and non-Hispanic blacks in order to give a sense of the magnitude of risks among Asians. Logistic regression models explored the effect of maternal risk factors and PTD on Asian subgroup differences in neonatal and post-neonatal mortality, using Japanese as the reference group. Across Asian subgroups, the differences ranged from 2.5- to 135-fold for maternal risks, and 2.2-fold for infant mortality rate. PTD was an important contributor to neonatal mortality differences. Maternal risk factors contributed to the disparities in post-neonatal mortality. Significant differences in perinatal health across Asian subgroups deserve ethnicity-specific interventions addressing PTD, teen pregnancy, maternal education, parity and access to prenatal care.

Neuropsychological outcome of children with intrauterine growth restriction: a 9-year prospective study

OBJECTIVE

The aim was to evaluate the effect of late-onset intrauterine growth restriction on the neuropsychological profile and on academic achievements at 9 years of age using a large-scale prospective paradigm.

STUDY DESIGN

We followed up 123 infants diagnosed with late-onset intrauterine growth restriction yearly for 9 years. They were matched with 63 children for gestation age and multiple socioeconomic factors and evaluated by an extensive neuropsychological battery to assess intelligence quotient, academic achievements, learning and memory, visuomotor skills, visuospatial integration, attention, language, executive functions, and creativity.

RESULTS

Children with intrauterine growth restriction had lower intelligence quotient and more frequent neuropsychological difficulties. Difficulties in executive functioning, inflexibility-creativity, and language, indicative of frontal lobe dysfunction, were typically affected by intrauterine growth restriction and were rarely identified in the control group. Learning difficulties accompanied by lower academic achievements were more prevalent in the intrauterine growth restriction group, particularly when anthropometric catch-up was incomplete.

CONCLUSIONS

The longitudinal findings reaffirm that functional coherence depends on preestablished structural growth and reorganization of the central nervous system. The neuropsychological profile at 9 years of age indicates that late-onset intrauterine growth restriction compromises frontal network functioning.

Prenatal care initiation among very low-income women in the aftermath of welfare reform: does pre-pregnancy Medicaid coverage make a difference?

OBJECTIVES

To examine pre-pregnancy Medicaid coverage and initiation of prenatal care among women likely eligible for Medicaid coverage regardless of pregnancy.

METHODS

The Pregnancy Risk Assessment Monitoring System (PRAMS) was used to identify very low-income women with Medicaid payment for delivery. We then compared prenatal care initiation among women with (Non-GAP) and without (Medicaid GAP) pre-pregnancy Medicaid coverage.

RESULTS

Rates of first trimester prenatal care were 47.3% for women in the Medicaid GAP, 70.0% for women who were not. The adjusted odds ratio for being in the Medicaid GAP and delayed prenatal care was 2.7 (95% CI 1.2, 6.2), although this varied by race/ethnicity and education. The relationship was strongest among White and Hispanic women with less than a high school education: OR=13.8, (95% CI 3.0, 62.7) and OR=19.0 (95% CI 2.4, 149.2), respectively.

CONCLUSIONS

Pre-pregnancy Medicaid coverage appears to be associated with early initiation of prenatal care. Almost a decade after welfare reform, it is essential to preserve the Medicaid expansions for pregnant women, foster Medicaid family planning waivers, and promote access to primary care and early prenatal care, particularly for very low-income women.

Differences in maternal and paternal transmission of coronary heart disease

BACKGROUND

Few studies have investigated the possible differential transmission of maternal and/or paternal coronary heart disease (CHD) to offspring, after accounting for sociodemographic characteristics.

METHODS

The Multigeneration Register was linked to hospital data in this study of all Swedish individuals born since 1932 and their parents. Registered cases of CHD between January 1, 1987, and December 31, 2001, were evaluated. Poisson regression was used to calculate standardized incidence ratios (SIRs) for men and women with mothers and/or fathers affected by CHD compared with men and women whose parents were not affected. All analyses were conducted in 2005.

RESULTS

Maternal transmission was stronger than paternal transmission and the confidence intervals did not overlap. For women, the overall SIRs were 1.43 (95% confidence interval [CI]=1.34-1.51) for maternal transmission and 1.17 (95% CI=1.11-1.23) for paternal transmission. For men, the corresponding SIRs were 1.55 (95% CI=1.50-1.60) and 1.41 (95% CI=1.37-1.45). Even higher SIRs were found in the youngest age groups, among those with both parents affected by coronary heart disease, and among those with premature parental CHD.

CONCLUSIONS

These findings might ultimately influence treatment decisions regarding risk factors and suggest the need for research focusing on genetic and intrauterine risk factors.

Outcomes in adulthood for children with foetal growth retardation. A linkage study from the Nord-Trøndelag Health Study (HUNT) and the Medical Birth Registry of Norway

OBJECTIVE

The aims were to examine the long-term functional outcome and risk of mood disorders in adulthood in individuals with foetal growth retardation.

METHOD

In a prospective cohort study of 7806 individuals aged 20-30 years, using linked data from the Health Survey of Nord-Trøndelag (HUNT-2) and the Medical Birth Registry of Norway, we studied the long-term effects of being born with a birth weight below the 10th percentile for gestational age (SGA).

RESULTS

SGA individuals had lower educational level (OR: 1.33), lower socioeconomic functioning level (OR: 1.77) and more frequent reported mood disorder in adulthood (OR: 1.26). Analyses of a substratum of infants born at term showed almost identical results.

CONCLUSION

Foetal growth retardation measured as SGA shows a moderate risk for lower education and socioeconomic level and for anxiety and/or depression in young adulthood. Issues concerning interventions for children at risk should be considered.

Social class inequalities in perinatal outcomes: Scotland 1980-2000

OBJECTIVE

To examine social class inequalities in adverse perinatal events in Scotland between 1980 and 2000 and how these were influenced by other maternal risk factors.

DESIGN

Population based study using routine maternity discharge data.

SETTING

Scotland.

PARTICIPANTS

All women who gave birth to a live singleton baby in Scottish hospitals between 1980 and 2000 (n=1,282,172).

MAIN OUTCOME MEASURES

Low birth weight (LBW), preterm birth, and small for gestational age (SGA).

RESULTS

The distribution of social class changed over time, with the proportion of mothers with undetermined social class increasing from 3.9% in 1980-84 to 14.8% in 1995-2000. The relative index of inequality (RII) decreased during the 1980s for all outcomes. The RII then increased between the early and late 1990s (LBW from 2.09 (95%CI 1.97, 2.22) to 2.43 (2.29, 2.58), preterm from 1.52 (1.44, 1.61) to 1.75 (1.65, 1.86), and SGA from 2.28 (2.14, 2.42) to 2.49 (2.34, 2.66) respectively). Inequalities were greatest in married mothers, mothers aged over 35, mothers taller than 164 cm, and mothers with a parity of one or more. Inequalities were also greater by the end of the 1990s than at the start of the 1980s for women of parity one or more and for mothers who were not married.

CONCLUSION

Despite decreasing during the 1980s, inequalities in adverse perinatal outcomes increased during the 1990s in all strata defined by maternal characteristics.

The relationship between the neighbourhood environment and adverse birth outcomes

Intrauterine growth retardation and preterm birth are more frequent in African-American women and women of lower socio-economic status, but the reasons for these disparities are not fully understood. The physical and social environments in which these women live may contribute to these disparities. We conducted a multilevel study to explore whether conditions of mothers' neighbourhood of residence contribute to adverse birth outcomes independent of individual-level determinants. We analysed data from 105 111 births in 1015 census tracts in Louisiana during 1997-98, merging it with data from other existing sources on neighbourhood socio-economic status, neighbourhood physical deterioration, and neighbourhood density of retail outlets selling tobacco, alcohol and foods. After controlling for individual-level sociodemographic factors, tract-level median household income was positively associated with both birthweight-for-gestational-age and gestational age at birth. Neighbourhood physical deterioration was associated with these birth outcomes in ecological analyses but only inconsistently associated with them after controlling for individual-level factors. Neither gestational age nor birthweight-for-gestational-age was associated with the neighbourhood density of alcohol outlets, tobacco outlets, fast-food restaurants or grocery supermarkets. We conclude that measures of neighbourhood economic conditions are associated with both fetal growth and the length of gestation independent of individual-level factors, but that readily available measures of neighbourhood retail outlets are not. Additional studies are needed to better understand the nature of environmental influences on birth outcomes.

Secular trends in socio-economic status and the implications for preterm birth

The rate of preterm birth in the developed world has been shown to be increasing, in part attributable to obstetric intervention. It has been suggested that this may be a differential increase between socio-economic groups. We aimed to assess whether the preterm rate in Norway is different in socio-economic groups defined by maternal education, and to determine the extent to which a difference is attributable to a socio-economic differential in obstetrical intervention, in terms of caesarean section or induction of labour. We used data from the Medical Birth Registry of Norway from 1980 to 1998 with preterm rate as the outcome and maternal educational level, marital status and obstetric intervention as exposure variables. In multivariable analyses, adjustment was made for maternal age, year of birth and birth order, and secular trends were assessed according to year of birth. The preterm birth rate was highest in the lowest socio-economic group. An increase of 25.2% in the preterm rate was seen over the observation period. No apparent differential was seen in the increase of the crude preterm rates between socio-economic groups, although in multivariable analyses there was a significant interaction between socio-economic group and time, implying a stronger effect of low education towards the end of the observation period attributable to demographic change. In conclusion, the preterm birth rate increased over time, but was mainly due to an increase in obstetric interventions. No closing of the gap between socio-economic groups was observed.

Intrauterine growth and intelligence within sibling pairs: findings from the Aberdeen children of the 1950s cohort

OBJECTIVE

The objective of this study was to examine whether the established positive association between birth weight and childhood psychometric intelligence is seen within singleton sibling pairs from the same family as well as between nonsiblings.

METHODS

We examined the association of intrauterine growth (measured as birth weight standardized for gender and gestational age) with psychometric intelligence (measured using the Moray House picture test) at 7 years old in a birth cohort of 9792 individuals who were singleton births occurring in Aberdeen, Scotland, between 1950 and 1956. We further compared this association within siblings with that between nonsiblings in the cohort; this family-based analysis included 1645 sibling pairs (N = 3290 individuals).

RESULTS

There was a positive linear association between birth weight and childhood psychometric intelligence at age 7 in the whole cohort, which remained with adjustment for a range of potential confounding factors. A one standard deviation increase in birth weight for gestational age z score was associated with a greater intelligence score in a regression model adjusting for sex, year of birth, paternal social class, maternal height, age, gravidity, and birth outside of marriage. The mean age difference between the siblings within each family pair was 2.2 years. In the family-based analysis there was no strong association between birth weight for gestation age z score and intelligence within sibling pairs from the same family, but there was a positive association between nonsiblings; the difference in these effects being unlikely to be due to chance. With additional adjustment for social class, maternal height, age, gravidity, and birth outside of marriage, the within-sibling pair effect was unaltered and the nonsibling effect attenuated, although an apparently robust positive association remained. In these adjusted analyses there was still evidence that the within-sibling effect differed from that between nonsiblings. We found no evidence that the main effects or the family-based analyses differed between males and females.

DISCUSSION

Our family-based analyses are consistent with one previous large family-based study that included >2500 sibling pairs and found no within-sibling-pairs association between birth weight and childhood intelligence, but did not make a direct statistical comparison between the within-sibling-pairs association and that between nonsiblings. In a second large study that included only sibling pairs of the same sex, in males there was a within-sibling-pairs association between birth weight and childhood intelligence. However, for females there was no within-sibling-pairs association. The authors commented that this sex difference was puzzling and needed replication. Although we had less power than this earlier study to assess sex differences, the point estimates and statistical tests in our study suggested that there was no sex difference.

CONCLUSIONS

The lack of any association within sibling pairs from the same family suggests that the association between birth weight and childhood intelligence in the general population of singletons is largely explained by fixed family factors that are closely matched in siblings of a similar age. These factors include family socioeconomic characteristics, parental education and intelligence, genetic factors and fixed maternal factors, such as her behaviors, size, and metabolic and cardiovascular health that are constant from one pregnancy to the next and could therefore affect her offspring growth and intelligence across all pregnancies.