Ruth Bell

Maternal overweight and obesity and the risk of congenital anomalies: a systematic review and meta-analysis.

CONTEXT Evidence suggests an association between maternal obesity and some congenital anomalies. OBJECTIVE To assess current evidence of the association between maternal overweight, maternal obesity, and congenital anomaly. DATA SOURCES MEDLINE, EMBASE, CINAHL, and Scopus (January 1966 through May 2008) were searched for English-language studies using a list of keywords. Reference lists from relevant review articles were also searched. STUDY SELECTION Observational studies with an estimate of prepregnancy or early pregnancy weight or body mass index (BMI) and data on congenital anomalies were considered. Of 1944 potential articles, 39 were included in the systematic review and 18 in the meta-analysis. Data Extraction and Synthesis Information was extracted on study design, quality, participants, congenital anomaly groups and subtypes, and risk estimates. Pooled odds ratios (ORs) comparing risk among overweight, obese, and recommended-weight mothers (defined by BMI) were determined for congenital anomaly groups and subtypes for which at least 150 cases had been reported in the literature. RESULTS Pooled ORs for overweight and obesity were calculated for 16 and 15 anomaly groups or subtypes, respectively. Compared with mothers of recommended BMI, obese mothers were at increased odds of pregnancies affected by neural tube defects (OR, 1.87; 95% confidence interval [CI], 1.62-2.15), spina bifida (OR, 2.24; 95% CI, 1.86-2.69), cardiovascular anomalies (OR, 1.30; 95% CI, 1.12-1.51), septal anomalies (OR, 1.20; 95% CI, 1.09-1.31), cleft palate (OR, 1.23; 95% CI, 1.03-1.47), cleft lip and palate (OR, 1.20; 95% CI, 1.03-1.40), anorectal atresia (OR, 1.48; 95% CI, 1.12-1.97), hydrocephaly (OR, 1.68; 95% CI, 1.19-2.36), and limb reduction anomalies (OR, 1.34; 95% CI, 1.03-1.73). The risk of gastroschisis among obese mothers was significantly reduced (OR, 0.17; 95% CI, 0.10-0.30). CONCLUSIONS Maternal obesity is associated with an increased risk of a range of structural anomalies, although the absolute increase is likely to be small. Further studies are needed to confirm whether maternal overweight is also implicated.

WHO European review of social determinants of health and the health divide

The European region has seen remarkable heath gains in those populations that have experienced progressive improvements in the conditions in which people are born, grow, live, and work. However, inequities, both between and within countries, persist. The review reported here, of inequities in health between and within countries across the 53 Member States of the WHO European region, was commissioned to support the development of the new health policy framework for Europe: Health 2020. Much more is understood now about the extent, and social causes, of these inequities, particularly since the publication in 2008 of the report of the Commission on Social Determinants of Health. The European review builds on the global evidence and recommends policies to ensure that progress can be made in reducing health inequities and the health divide across all countries, including those with low incomes. Action is needed--on the social determinants of health, across the life course, and in wider social and economic spheres--to achieve greater health equity and protect future generations.

Particulate Air Pollution and Fetal Health A Systematic Review of the Epidemiologic Evidence

Background: Research on the potential impact of air pollution on the health of adults and children has grown rapidly over the last decade. Recent studies have suggested that air pollution could also be associated with adverse effects on the developing fetus. This systematic review evaluates the current level of epidemiologic evidence on the association between ambient particulate air pollution and fetal health outcomes. We also suggest further research questions. Methods: Using database searches and other approaches, we identified relevant publications published between 1966 and 2001 in English. Articles were included if they reported original data on birthweight, gestational age at delivery, or stillbirth related to directly measured nonaccidental exposure to particulate matter. Results: Twelve studies met the inclusion criteria. There was little consistency in the evidence linking particulate air pollution and fetal outcomes. Many studies had methodologic weaknesses in their design and adjustment for confounding factors. Even in well-designed studies, the reported magnitude of the effects was small and inconsistently associated with exposure at specific stages of pregnancy. Conclusions: The currently available evidence is compatible with either a small adverse effect of particulate air pollution on fetal growth and duration of pregnancy or with no effect. Further research should be directed toward clarifying and quantifying these possible effects and generating testable hypotheses on plausible biologic mechanisms.

Trends in prevalence and outcomes of pregnancy in women with pre‐existing type I and type II diabetes

Objective  To describe recent trends in prevalence, outcomes and indicators of care for women with pre‐existing type I or type II diabetes.

Physical activity in pregnancy: a qualitative study of the beliefs of overweight and obese pregnant women

BackgroundWhilst there has been increasing research interest in interventions which promote physical activity during pregnancy few studies have yielded detailed insights into the views and experiences of overweight and obese pregnant women themselves. The qualitative study described in this paper aimed to: (i) explore the views and experiences of overweight and obese pregnant women; and (ii) inform interventions which could promote the adoption of physical activity during pregnancy.MethodsThe study was framed by a combined Subtle Realism and Theory of Planned Behaviour (TPB) approach. This enabled us to examine the hypothetical pathway between beliefs and physical activity intentions within the context of day to day life. The study sample for the qualitative study was chosen by stratified, purposive sampling from a previous study of physical activity measurements in pregnancy. Research participants for the current study were recruited on the basis of Body Mass Index (BMI) at booking and parity. Semi-structured, in-depth interviews were conducted with 14 overweight and obese pregnant women. Data analysis was undertaken using a Framework Approach and was informed by TPB.ResultsHealthy eating was often viewed as being of greater importance for the health of mother and baby than participation in physical activity. A commonly cited motivator for maintaining physical activity during pregnancy is an aid to reducing pregnancy-related weight gain. However, participants often described how they would wait until the postnatal period to try and lose weight. A wide range of barriers to physical activity during pregnancy were highlighted including both internal (physical and psychological) and external (work, family, time and environmental). The study participants also lacked access to consistent information, advice and support on the benefits of physical activity during pregnancy.ConclusionsInterventions to encourage recommended levels of physical activity in pregnancy should be accompanied by accessible and consistent information about the positive effects for mother and baby. More research is required to examine how to overcome barriers to physical activity and to understand which interventions could be most effective for overweight/obese pregnant women. Midwives should be encouraged to do more to promote activity in pregnancy.

Maternal body mass index and the risk of fetal and infant death: a cohort study from the North of England

BACKGROUND Early pregnancy obesity (body mass index, BMI, ≥ 30 kg/m(2)) carries significant health implications. This cohort study investigates the association between early pregnancy BMI and the risk of fetal and infant death in pregnancies not affected by congenital anomalies or pre-gestational diabetes. METHODS Data on singleton pregnancies delivered during 2003-2005 at five hospitals were linked with data from three regional registers: the Northern Perinatal Mortality Survey, the Northern Diabetes in Pregnancy Survey and the Northern Congenital Abnormality Survey. Logistic regression models were used to determine the crude and adjusted odds ratios (aOR) of a spontaneous fetal death (≥ 20 weeks gestation) and infant death (aged up to 1 year), among underweight (BMI <18.5 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) and obese women compared with women of recommended BMI (18.5-24.9 kg/m(2)). RESULTS Obese women were at significantly increased risks of both fetal death [aOR = 2.32 (95% confidence interval: 1.64-3.28), P< 0.001] and infant death [aOR = 1.97 (1.13-3.45), P= 0.02]. Continuous analyses revealed a V-shaped relationship between BMI and the risk of fetal and infant death, with a minimum risk at 23 kg/m(2), and significantly increased risk thereafter for both fetal death [aOR, per unit = 1.07 (1.05-1.10), P< 0.001] and infant death [aOR, per unit = 1.06 (1.02-1.10), P= 0.007]. No significant excess risks, however, were identified for either maternal underweight [fetal death: aOR = 0.98 (0.42-2.25), P= 0.96; infant death: aOR = 1.89 (0.73-4.88), P= 0.19] or maternal overweight [fetal death: aOR = 1.34 (0.94-1.89), P= 0.10; infant death: aOR = 1.35 (0.79-2.32), P= 0.27] as categories. Except for higher rates of pre-eclampsia among stillbirths, no specific cause of death could explain the increased odds of fetal and infant death among the obese. CONCLUSIONS Early pregnancy obesity is significantly associated with fetal and infant death, independent of the known relationships with congenital anomalies and maternal pre-gestational diabetes.

Does particulate air pollution contribute to infant death? A systematic review.

There is now substantial evidence that both short- and long-term increases in ambient air pollution are associated with increased mortality and morbidity in adults and children. Children’s health is particularly vulnerable to environmental pollution, and infant mortality is still a major contributor to childhood mortality. In this systematic review we summarize and evaluate the current level of epidemiologic evidence of an association between particulate air pollution and infant mortality. We identified relevant publications using database searches with a comprehensive list of search terms and other established search methods. We included articles in the review according to specified inclusion criteria. Fifteen studies met our inclusion criteria. Evidence of an association between particulate air pollution and infant mortality in general was inconsistent, being reported from locations with largely comparable pollution levels. There was some evidence that the strength of association with particulate matter differed by subgroups of infant mortality. It was more consistent for post-neonatal mortality due to respiratory causes and sudden infant death syndrome. Differential findings for various mortality subgroups within studies suggest a stronger association of particulate air pollution with some causes of infant death. Research is needed to confirm and clarify these links, using the most appropriate methodologies for exposure assessment and control of confounders.

Changing patterns of perinatal death, 1982-2000: a retrospective cohort study.

Objective: To describe trends in cause specific stillbirth and neonatal mortality. Design: Retrospective cohort study. Setting and participants: 686 860 births in 1982–2000, to mothers resident in the Northern Region of England. Main outcome measures: Cause specific stillbirth and neonatal mortality; rate ratios (RR) and 95% confidence intervals (CI) in 1991–2000 compared with 1982–1990. Results: In singletons, rates of stillbirth and neonatal mortality declined over time (RR stillbirths, 0.81 (95% CI 0.76 to 0.87); RR neonatal mortality, 0.76 (95% CI 0.70 to 0.82)). Death from congenital anomalies declined substantially for both stillbirths (RR 0.52; 95% CI 0.40 to 0.68) and neonatal mortality (RR 0.58; 95% CI 0.51 to 0.67). Mortality due to intrapartum hypoxia also fell, by nearly 50% for stillbirths and 30% for neonatal deaths. There was no reduction in stillbirths due to antepartum hypoxia in babies weighing ⩾ 2500 g, or in mortality attributed to infection. In multiples, the risk of death was higher (RR stillbirths, 4.13 (95% CI 3.68 to 4.64); RR neonatal death, 7.82 (95% CI 7.13 to 8.58)). Stillbirth rates declined significantly (RR 0.71; 95% CI 0.57 to 0.89) but neonatal mortality did not (RR 0.91; 95% CI 0.77 to 1.08). There was no reduction in neonatal mortality resulting from prematurity, or in mortality from congenital anomalies. Conclusions: There is considerable overlap in the causes of stillbirth and neonatal mortality. Future progress in reducing perinatal mortality requires better understanding of the aetiology of antepartum stillbirth, of the excess risks of prematurity facing multiple births, particularly in the light of their increasing incidence, and of strategies to prevent perinatal infection.

Maternal body mass index and congenital anomaly risk: a cohort study

Objective:To investigate the association between maternal body mass index (BMI) and major, structural congenital anomalies.Design:Cohort study using prospectively collected data.Methods:Data on all singleton pregnancies booked at five maternity units in the north of England between 01 January 2003 and 31 December 2005 and data on congenital anomalies notified to the Northern Congenital Abnormality Survey were linked using key variables. Maternal pre-gestational diabetic status was derived from the Northern Diabetes in Pregnancy Survey. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated by maximum-likelihood logistic regression models, with missing values modelled as explicit categories.Results:There was a total of 41 013 singleton pregnancies during the study period, of which 682 were affected by a structural congenital anomaly, a total prevalence of 166 (95% CI: 154, 179) per 10 000 registered births. Overall, the risk of a congenital anomaly was significantly increased among the maternal underweight (BMI⩽18.5 kg m–2; aOR=1.60, 95% CI: 1.09, 2.36; P=0.02) and maternal obese groups (BMI⩾30 kg m–2; aOR=1.30, 95% CI: 1.03, 1.63; P=0.03), but not for maternal overweight (BMI=25–29.9 kg m–2; aOR=0.85, 95% CI: 0.68, 1.06; P=0.15), compared with mothers of recommended BMI. Maternal obesity was associated with significantly increased risk of ventricular septal defect (aOR=1.56, 95% CI: 1.01, 2.40; P=0.04), cleft lip (aOR=3.71, 95% CI: 1.05, 13.10; P=0.04) and eye anomalies (aOR=11.36, 95% CI: 2.25, 57.28; P=0.003). Maternal underweight was associated with significantly increased risks of atrial septal defect (aOR=2.86, 95% CI: 1.18, 6.96; P=0.02), genital anomalies (aOR=6.30, 95% CI: 1.58, 25.08; P=0.009) and hypospadias (aOR=8.77, 95% CI: 1.42, 54.29; P=0.02).Conclusions:We found an overall increased risk of congenital anomalies in women who are obese and women who are underweight compared with women of recommended weight. Women should be made aware of these risks and supported to optimize their weight before pregnancy.

What helps and hinders midwives in engaging with pregnant women about stopping smoking? A cross-sectional survey of perceived implementation difficulties among midwives in the North East of England

BackgroundAround 5,000 miscarriages and 300 perinatal deaths per year result from maternal smoking in the United Kingdom. In the northeast of England, 22% of women smoke at delivery compared to 14% nationally. Midwives have designated responsibilities to help pregnant women stop smoking. We aimed to assess perceived implementation difficulties regarding midwives’ roles in smoking cessation in pregnancy.MethodsA self-completed, anonymous survey was sent to all midwives in northeast England (n = 1,358) that explores the theoretical explanations for implementation difficulties of four behaviours recommended in the National Institute for Health and Clinical Excellence (NICE) guidance: (a) asking a pregnant woman about her smoking behaviour, (b) referring to the stop-smoking service, (c) giving advice about smoking behaviour, and (d) using a carbon monoxide monitor. Questions covering Michie et al.’s theoretical domain framework (TDF), describing 11 domains of hypothesised behavioural determinants (i.e., ‘knowledge’, ‘skills’, ‘social/professional role/identity’, ‘beliefs about capabilities’, ‘beliefs about consequences’, ‘motivation and goals’, ‘memory’, ‘attention and decision processes’, ‘environmental context and resources’, ‘social influences’, ‘emotion’, and ‘self-regulation/action planning’), were used to describe perceived implementation difficulties, predict self-reported implementation behaviours, and explore relationships with demographic and professional variables.ResultsThe overall response rate was 43% (n = 589). The number of questionnaires analysed was 364, following removal of the delivery-unit midwives, who are not directly involved in providing smoking-cessation services. Participants reported few implementation difficulties, high levels of motivation for all four behaviours and identified smoking-cessation work with their role. Midwives were less certain about the consequences of, and the environmental context and resources available for, engaging in this work relative to other TDF domains. All domains were highly correlated. A principal component analysis showed that a single factor (‘propensity to act’), derived from all domains, explained 66% of variance in theoretical domain measures. The ‘propensity to act’ was predictive of the self-reported behaviour ‘Refer all women who smoke……to NHS Stop Smoking Services’ and mediated the relationship between demographic variables, such as midwives’ main place of work, and behaviour.ConclusionsOur findings advance understanding of what facilitates and inhibits midwives’ guideline implementation behaviours in relation to smoking cessation and will inform the development of current practice and new interventions. Using the TDF as a self-completion questionnaire is innovative, and this study supports previous research that the TDF is an appropriate tool to understand the behaviour of healthcare professionals.