Community-based Pregnancy Cohort Research Articles

Association of illness perceptions and exclusive breastfeeding intentions among pregnant women with chronic conditions: A community-based pregnancy cohort study

ObjectiveWe examined whether changes in illness perceptions from preconception to pregnancy were associated with intentions to exclusively breastfeed to 6 months postpartum among women with chronic physical health conditions. MethodsWe analyzed self-reported cross-sectional questionnaire data collected in the third trimester from 361 women with chronic conditions enrolled in a community-based cohort study (Alberta, Canada). For individual and total illness perceptions, measured with the Brief Illness Perception Questionnaire, women were classified using change scores (preconception minus pregnancy) into one of the following groups: “worsening,” “improving,” or “stable” in pregnancy. Intention to exclusively breastfeed was defined as plans to provide only breast milk for the recommended first 6 months after birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression modelling, with the “stable” group as the reference and controlling for demographic factors, chronic condition duration and medication, prenatal class attendance, and social support. ResultsOverall, 61.8% of women planned to exclusively breastfeed to 6 months. Worsened total illness perceptions (adjusted OR 0.50, 95% CI 0.30–0.82) as well as perceptions of worsened identity (i.e., degree of symptoms; adjusted OR 0.49, 95% CI 0.28–0.85) or consequences (i.e., impact on functioning; adjusted OR 0.60, 95% CI 0.34–1.06) were associated with lower odds of intending to exclusively breastfeed to 6 months. ConclusionsWomen who perceive their illness experience to worsen during pregnancy are less likely to plan to exclusively breastfeed to 6 months in accordance with public health recommendations.

Breastfeeding difficulties in the first 6 weeks postpartum among mothers with chronic conditions: a latent class analysis

BackgroundBreastfeeding difficulties frequently exacerbate one another and are common reasons for curtailed breastfeeding. Women with chronic conditions are at high risk of early breastfeeding cessation, yet limited evidence exists on the breastfeeding difficulties that co-occur in these mothers. The objective of this study was to explore clusters of breastfeeding difficulties experienced up to 6 weeks postpartum among mothers with chronic conditions and to examine associations between chronic condition types and breastfeeding difficulty clusters.MethodsWe analyzed 348 mothers with chronic conditions enrolled in a prospective, community-based pregnancy cohort study from Alberta, Canada. Data were collected through self-report questionnaires. We used latent class analysis to identify clusters of early breastfeeding difficulties and multinomial logistic regression to examine whether types of chronic conditions were associated with these clusters, adjusting for maternal and obstetric factors.ResultsWe identified three clusters of breastfeeding difficulties. The “physiologically expected” cluster (51.1% of women) was characterized by leaking breasts and engorgement (reference outcome group); the “low milk production” cluster (15.4%) was discerned by low milk supply and infant weight concerns; and the “ineffective latch” cluster (33.5%) involved latch problems, sore nipples, and difficulty with positioning. Endocrine (adjusted relative risk ratio [RRR] 2.34, 95% CI 1.10–5.00), cardiovascular (adjusted RRR 2.75, 95% CI 1.01–7.81), and gastrointestinal (adjusted RRR 2.51, 95% CI 1.11–5.69) conditions were associated with the low milk production cluster, and gastrointestinal (adjusted RRR 2.44, 95% CI 1.25–4.77) conditions were additionally associated with the ineffective latch cluster.ConclusionHalf of women with chronic conditions experienced clusters of breastfeeding difficulties corresponding either to low milk production or to ineffective latch in the first 6 weeks postpartum. Associations with chronic condition types suggest that connections between lactation physiology and disease pathophysiology should be considered when providing breastfeeding support.

Association of postpartum medication practices with early breastfeeding cessation among mothers with chronic conditions: A prospective cohort study.

Use of medications is a common concern for breastfeeding women, particularly when they are strongly needed or unavoidable to manage maternal chronic conditions. Yet the influence of medication usage patterns on breastfeeding duration in mothers with chronic conditions is unclear. The objective of this study was to examine whether postpartum medication practices were associated with shorter breastfeeding duration or earlier than planned breastfeeding cessation among mothers with chronic conditions. We analyzed 346 mothers with chronic conditions enrolled in a prospective, community-based pregnancy cohort study (Alberta, Canada) who initiated breastfeeding after birth. Data were collected through self-report questionnaires spanning late pregnancy to 6months postpartum. Based on reported use of preexisting medications while breastfeeding, women were classified as continuing medications (reference group), discontinuing one or more medications, or those who did not use preexisting medications. Cox proportional hazards regression was used to analyze the association of medication practices and overall breastfeeding duration in weeks. Logistic regression was used to analyze the association of medication practices and earlier than planned breastfeeding cessation. Multivariable models adjusted for demographic and health-related factors. Overall, 30.6% of women with chronic conditions stopped breastfeeding in the first 6months, almost all of whom did so earlier than planned. In multivariable models, medication discontinuation was significantly associated with shorter breastfeeding duration (adjusted hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.03-2.70) and earlier than planned breastfeeding cessation (adjusted odds ratio [OR] 1.85, 95% CI 1.01-3.42), whereas medication non-use was not associated with differences in breastfeeding outcomes. Women with chronic conditions who discontinued preexisting medications while breastfeeding had significantly shorter breastfeeding duration and were less likely to meet their breastfeeding goals in the first 6months postpartum compared to women who continued preexisting medications.

Associations Between Maternal Nutrition in Pregnancy and Child Blood Pressure at 4–6 Years: A Prospective Study in a Community-Based Pregnancy Cohort

The intrauterine environment may influence offspring blood pressure, with effects possibly extending into adulthood. The associations between prenatal nutrition and offspring blood pressure, alone or in combination with other sociodemographic or behavioral factors, are unclear. To investigate the associations of maternal dietary patterns and plasma folate concentrations with blood pressure in children aged 4-6 years, and assess the potential effect modifications by child sex, maternal race, pre-pregnancy overweight or obesity, maternal smoking, and breastfeeding. Participants were 846 mother-child dyads from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. Maternal nutrition was characterized by the Healthy Eating Index 2010 (HEI) scores and plasma folate concentrations in pregnancy. We calculated the systolic blood pressure (SBP) and diastolic blood pressure percentiles, incorporating sex, age, and height, and categorized children as either having high blood pressure (HBP; ≥90th percentile) or normal blood pressure. Linear regressions were performed to quantify the associations between maternal nutrition and continuous blood pressure percentiles, and Poisson regressions were used to estimate the incidence rate ratio (IRR) of binary HBP. We examined the effect modifications using interaction models. Mean HEI scores and folate concentrations were 60.0 (SD, 11.3) and 23.1ng/mL (SD, 11.1), respectively. Based on measurements at 1 visit, 29.6% of the children were defined as having HBP. Maternal HEI scores and plasma folate concentrations were not associated with child blood pressure percentiles or HBP in the full cohort. Among mothers self-identified as white, there was an inverse relationship between maternal HEI score and child SBP percentile (β, -0.40; 95%CI: -0.75 to -0.06). A maternal HEI score above 59 was associated with a reduced risk of HBP in girls (IRR, 0.53; 95% CI: 0.32-0.88). No modified associations by pre-pregnancy overweight or obesity, maternal smoking, or breastfeeding were indicated. We found little evidence for effects of maternal nutrition during pregnancy on childhood blood pressure, but detected sex- and race-specific associations. The study contributes to the evolving scientific inquiry regarding developmental origins of disease.

Children’s language abilities at age 10 and exposure to intimate partner violence in early childhood: Results of an Australian prospective pregnancy cohort study

BackgroundApproximately one in four children in Australia have mothers who experience intimate partner violence (IPV). These children are at risk of poor mental health. Less is known about their language outcomes, despite evidence that childhood adversity threatens neurodevelopment, and the home environment effects language development. ObjectiveThis study aimed to examine the relationship between early childhood IPV exposure and language outcomes (receptive vocabulary, general language, pragmatic language) at age 10, including the influence of maternal depressive symptoms. Participants and settingParticipants were 615 mothers and their first-born child participating in a prospective, community-based pregnancy cohort study in Melbourne. MethodsMothers reported their experience of IPV and depressive symptoms in the first and fourth year postpartum. At 10 years postpartum, children’s receptive vocabulary was directly assessed and mothers reported on their child’s general and pragmatic language skills. ResultsExposure to IPV was related to scores indicating poorer abilities in receptive vocabulary (d=-0.26, p = .009), general language (d = 0.23, p = .047) and pragmatic language skills (d = 0.41, p < .001) at age 10. After adjusting for maternal depressive symptoms, evidence remained for the relationship with pragmatic language (d=-0.32, p = .006), and a trend for receptive vocabulary (d=-0.20, p = .052). ConclusionsAt a community-level, children whose mothers experienced IPV during the child’s first four years had poorer language skills in middle childhood than children whose mothers did not experience IPV. This is important because poor child language skills are associated with adverse outcomes across the lifespan including academic under-achievement and mental health problems. Clinical implications are discussed.

Maternal substance use in pregnancy: Differential prediction by childhood adversity subtypes

Substance use in pregnancy, including alcohol use, drug use, or smoking, is associated with poor health outcomes for both the mother and her unborn child. Building on previous research that has examined the cumulative impact of Adverse Childhood Experiences (ACEs) on maternal binge drinking and alcohol use in pregnancy, the current study sought to examine the association between maternal ACEs and substance use in pregnancy more broadly, including alcohol use, binge drinking, smoking, and drug use. Furthermore, we also examined how different adversity subtypes, including sexual abuse, family violence (physical abuse, emotional abuse), and household dysfunction, differentially predict maternal substance use behavior. A sample of 1994 women were recruited between 2008 and 2011 from a community-based pregnancy cohort in Calgary, Canada. Self-reported information on exposure to ACEs prior to the age of 18 years and maternal substance usewere collected. Examining ACE subtypes, medium effects were observed for the role of household-dysfunction on binge drinking, drug use, and smoking in pregnancy, while only small effects were observed for family violence on binge drinking, drug use, and smoking. There were no significant effects for sexual abuse after controlling for covariates. A dose-response association between the number of ACEs and substance use in pregnancy was also demonstrated. Increased support prior to, and in pregnancy, particularly for women with a history of childhood adversity, is needed to reduce substance use behaviors in pregnancy.

Women\u2019s recall of health care provider counselling on gestational weight gain (GWG): a prospective, population-based study

BackgroundPrenatal care has been validated to provide medical and educational counselling intended to reduce the risk of adverse pregnancy conditions and improve the maternal and fetal outcomes. Prenatal targeted information regarding nutrition, lifestyle, and weight gain is predictive of meeting Institute of Medicine (IOM) 2009 gestational weight gain (GWG) guidelines. There is limited information about women’s experiences with these prenatal counselling domains, particularly in women who do not meet GWG recommendations. The objective of this study was to evaluate the impact of women’s recall of prenatal counselling and its effect on meeting their GWG within guidelines in a prospective, community-based pregnancy cohort.MethodsA sample of 2909 women with singleton pregnancies was drawn from the prospective community-based pregnancy cohort All Our Families from Alberta, Canada. Women were stratified into three GWG groups, adequate, inadequate, and excessive GWG, based on pre-pregnancy BMI and the adherence to the Institute of Medicine weight gain in pregnancy guidelines. At less than 25 and 34 to 36 weeks’ gestation, maternal socio-demographic information and women’s recall of prenatal counselling experiences was collected through self-administered questionnaires. Multivariate logistic regression analyses tested GWG strata impact on women’s recall of the prenatal counselling advice in eight domains of nutrition, lifestyle, and weight management during pregnancy.ResultsAdequate GWG was reached by 35.9% of women, 46.5% gained excessive and 17.6% gained inadequate weight. Women who were overweight and obese prior to pregnancy were more likely to gain excessive weight than women who were normal weight (OR 3.3, 95% CI 2.6–4.1; and OR 2.9, 95% CI 2.1–3.9, respectively). Most women reported having no difficulties in finding prenatal care, felt comfortable with their health care provider and were satisfied with the answers received. There was no difference in the recall of prenatal advice received in any of the eight domains of prenatal counselling assessed among women with appropriate and non-optimal GWG.ConclusionWomen with adequate and non-optimal GWG received comparable prenatal counselling on nutrition, weight gain, and lifestyle modifications. There remain missed opportunities in targeting prenatal counselling advice to women at risk for suboptimal or excessive GWG.

Maternal perceptions of childhood vaccination: explanations of reasons for and against vaccination

BackgroundUnderstanding reasons for and against vaccination from the parental perspective is critical for designing vaccination campaigns and informing other interventions to increase vaccination uptake in Canada. The objective of this study was to understand maternal vaccination decision making for children.MethodsMothers participating in a longitudinal community-based pregnancy cohort, the All Our Babies study in Calgary, Alberta, completed open-ended survey questions providing explanations for the vaccination status of their child by 24 months postpartum. Qualitative responses were linked to administrative vaccination records to examine survey responses and recorded child vaccination status.ResultsThere were 1560 open-ended responses available; 89% (n = 1391) provided explanations for vaccinating their children, 5% (n = 79) provided explanations for not vaccinating/delaying, and 6% (n = 90) provided explanations for both. Themes were similar for those vaccinating and not vaccinating/delaying; however, interpretations were different. Two broad themes were identified: Sources of influence and Deliberative Processes. Sources of influence on decision making included personal, family, and external experiences. Deliberative Processes included risk, research, effectiveness, and balancing risks/benefits. Under Deliberative Processes, responsibility was a category for those vaccinating; while choice, instrumental/practical, and health issues were categories for those not vaccinating/delaying. Mothers’ levels of conviction and motivation provided a Context for understanding their decision making perspectives.ConclusionsVaccination decision making is complex and impacted by many factors that are similar but contribute to different decisions depending on mothers’ perspectives. The results of this study indicate the need to examine new intervention approaches to increase uptake that recognize and address feelings of pressure and parental commitment to choice.

Pregnancy Intention and Maternal Alcohol Consumption.

To evaluate whether women planning a pregnancy are less likely to use alcohol in early pregnancy than those with unintended pregnancies. Right From the Start (2000-2012) is a prospective, community-based pregnancy cohort. Maternal demographic, reproductive, and behavioral data were collected in telephone interviews at enrollment (mean±standard deviation 48±13 days of gestation) and later in the first trimester (mean±standard deviation 85±21 days of gestation). Alcohol consumption characteristics were included in the interviews. We used logistic regression to investigate the association of pregnancy intention with alcohol use. Among 5,036 women, 55% reported using alcohol in the first trimester with 6% continuing use at the first-trimester interview. Pregnancy was planned by 70% of participants. Alcohol use occurred in 55% and 56% of intended and unintended pregnancies, respectively (P=.32). Adjusting for confounders, women with intended pregnancies were 31% less likely to consume any alcohol in early pregnancy (adjusted odds ratio [OR] 0.69, 95% confidence interval [CI] 0.60-0.81) or binge drink (adjusted OR 0.68, 95% CI 0.54-0.86). Most women, regardless of intention, stopped or decreased alcohol consumption in early pregnancy. The majority of women, irrespective of intention, stopped or decreased drinking after pregnancy recognition. This suggests promoting early pregnancy awareness could prove more effective than promoting abstinence from alcohol among all who could conceive.

Timeliness and completeness of routine childhood vaccinations in children by two years of age in Alberta, Canada.

Assessing timeliness and completeness of vaccine administration is important for evaluating the effectiveness of immunization programs. Few studies have reported timeliness, particularly in Canada. The objective of this study was to examine timeliness of the receipt of vaccination for each routine childhood recommended vaccine by 24 months of age among children in a community-based pregnancy cohort in Calgary, Alberta. Survey data from a community-based pregnancy cohort in Alberta were linked to Public Health vaccination records of children (n = 2763). The proportion of children receiving early, timely, delayed, or no vaccination was calculated. A dose was considered early if it was administered before the recommended age in days as per the vaccination schedule, timely if administered at any time from start of recommended age in days to age in days when delay counts were initiated, and delayed if it was administered on or after age in days when delay counts were initiated. Series completion rates were also calculated. For multi-dose vaccines, over 80% of children had timely doses at 2, 4 and 6 months. By 12 months, this proportion decreased to 65% (95% CI: 63%-66%) for meningococcal conjugate group C, 61% (95% CI: 59%-62%) for measles antigen-containing vaccines and 64% (95% CI: 62%-65%) for varicella antigen-containing vaccines. At 18 months, only 55% (95% CI: 53%-56%) of the children had a timely 4th dose of diphtheria, acellular pertussis, tetanus, polio, and Haemophilus influenzae type b vaccine. Eventual series completion rate for all recommended vaccines was 77% (95% CI: 75%-79%). The timeliness and completeness of routine childhood vaccination in preschool children in this community-based pregnancy cohort is lower than provincial targets. Data on timeliness of vaccination can inform further work on barriers and enablers to vaccination in order to meet provincial targets.

Validation of maternal recall of early pregnancy medication exposure using prospective diary data

PurposeData about maternal recall accuracy for classifying early pregnancy medication exposure are meager. Nonetheless, studies often rely on recall to evaluate potential impact of pharmaceuticals on the developing fetus. MethodsRight from the Start is a community-based pregnancy cohort that enrolled women from North Carolina, Tennessee, and Texas. A subset of 318 women participated in daily medication diaries initiated before conception (2006–2012). We examined nonsteroidal anti-inflammatory drugs (NSAIDs) as an example of a drug type that is difficult to study due to its intermittent and primarily over-the-counter use as well as its incomplete documentation in medical and pharmaceutical records. Selective serotonin reuptake inhibitors (SSRI) were assessed as a prescription medication comparator. Maternal recall of NSAID and SSRI use in early pregnancy was examined by comparing diary data (gold standard) to first-trimester interview. ResultsSensitivity and specificity for recall of NSAID exposure were 78.6% and 62.3%, respectively (kappa statistic: 0.41), with 72.3% agreement for exposure classification. Sensitivity and specificity for recall of SSRI exposure were 77.8% and 99.0%, respectively (kappa statistic: 0.79), with 97.8% agreement. ConclusionsOur findings suggest the validity of maternal recall varies with medication type and prospective data collection should be prioritized when studying early pregnancy drug exposures.

Pre-pregnancy body mass index (BMI) and macrosomia in a Canadian birth cohort

Objective: To compare demographic characteristics and maternal, fetal, neonatal, and pregnancy outcomes of term macrosomic infants of obese and non-obese mothers.Methods: A sample of 1996 singleton, term deliveries was drawn from the All Our Babies Cohort, a prospective, community-based pregnancy cohort. Maternal self-reported socio-demographic and anthropometric information was linked to the clinical data on pregnancy and birth events abstracted from electronic health records. Demographic, obstetrical characteristics and maternal, fetal, neonatal, and pregnancy outcomes of macrosomic infants in obese, overweight, and normal weight women were compared. Multinomial regression analysis assessed the risk factors of macrosomia in primiparous and multiparous women stratified by maternal pre-pregnancy BMI, controlling for confounding variables.Results: Macrosomia affected 10% of pregnancies in the study. Mothers whose infants were macrosomic were more likely to be Caucasian, obese, have had previous deliveries, undergo induction of labour and delivery by emergency C-section, particularly for labour abnormalities. Macrosomic infants were more likely to be delivered postdates, have meconium stained liquor and require resuscitation at birth. There were no significant differences in birth and neonatal outcomes of macrosomic pregnancies between obese, overweight and normal weight women. Pre-pregnancy BMI and gestational age at delivery were risk factors for macrosomia in all women. Ethnicity and history of delivery of a macrosomic infant were additional independent risk factors in multiparas.Conclusions: Obesity in pregnancy increases the risk of delivery of a macrosomic infant in both primiparous and multiparous women. The maternal, fetal and neonatal outcomes of macrosomic pregnancies are similar in obese and normal weight women.

The Influence of Back Pain and Urinary Incontinence on Daily Tasks of Mothers at 12 Months Postpartum.

ObjectiveThe present study examined back pain (BP) and/or urinary incontinence (UI) impact on the ability to perform daily tasks at 12 months after childbirth in healthy reproductive women who sought maternity care in community based family practice clinics.MethodsThis study is a secondary analysis from the All Our Babies Study, a prospective, community-based pregnancy cohort in Calgary, Alberta. Maternal self-reported information on demographics, lifestyle, experiences with pregnancy and childbirth, occurrence of BP, UI and consequent impairment of daily tasks were collected by questionnaires administered before 25 weeks, at 34-36 weeks gestation and at 4 and 12 months postpartum. The occurrence and severity of BP and UI at one year after childbirth was assessed using descriptive and bivariate analyses. Logistic regression models examined the association between demographic and obstetrical variables and the severity of functional impairment due to UI and BP.ResultsFrom 1574 women with singleton pregnancies included in the study, 1212 (77%) experienced BP, 773 (49%) UI, and 620 (40%) both BP and UI. From the 821 women reporting impairment of daily tasks due to BP, 199 (24 %) were moderately and 90 (11%) severely affected with the remainder, 532 (64%) being mildly affected. From 267 women with functional impairment due to UI, 52 (19%) reported moderately to severe impairment in their ability to perform daily tasks. Obesity and parity were risk factors for impairment of daily functioning due to BP, whereas obesity and vaginal delivery increased the risk of moderate to severe impairment due to UI.ConclusionsBP and UI are common occurrences 1 year after childbirth. Maternal performance of daily tasks and women’s health and quality of life are more often impaired due to BP than UI. Our study brings new evidence of the risk factors that predict severity and impact of these conditions on women functioning at 12 months postpartum.

Effect of depressive and anxiety symptoms during pregnancy on risk of obstetric interventions.

The effect of prenatal mental health on the risk of obstetric interventions is unclear. The present study examined the associations between depressive and anxiety symptoms in the second and third trimesters and mode of delivery, epidural use and labor induction in a large community-based pregnancy cohort, in Alberta, Canada. Women who had singleton pregnancies, delivered in hospital, and had medical data were selected (n = 2825). Obstetric intervention data were obtained from the medical records, and depressive and anxiety symptoms were measured by the Edinburgh Postnatal Depression Scale and the Spielberger State Anxiety Inventory. Data were evaluated with multivariate multinomial and logistic regression analyses using a hierarchical modeling. After accounting for factors known to increase the risk of each intervention, including demographic variables, smoking, hospital site, gestational age, previous history of cesarean delivery, prepregnancy body mass index, assisted conception, and antepartum risk score, the only mental health variable associated with obstetric interventions was depressive symptoms in the third trimester, which increased the risk of emergency cesarean delivery (adjusted odds ratio, 2.04; 95% confidence interval, 1.26-3.29). No associations were found between antenatal depressive and anxiety symptoms and other obstetric interventions. The present findings support an association between depressive symptoms and adverse obstetric outcomes and suggest that anxiety and depression may have different effects on obstetric outcomes. Understanding the mechanism in which depression increases the risk of emergency cesarean birth needs further research.

Pre-pregnancy Body Mass Index (BMI) and delivery outcomes in a Canadian population.

BackgroundWorldwide there has been a dramatic increase in the prevalence of overweight and obesity in women of childbearing age. Growing evidence suggests that maternal overweight and obesity is associated with poor maternal and perinatal outcomes. This study evaluated the impact of maternal pre-pregnancy overweight and obesity on pregnancy, labour and delivery outcomes in a cohort of women with term, singleton pregnancies cared for by family physicians in community based practices.MethodsThis study is a secondary analysis of the All Our Babies Cohort, a prospective, community-based pregnancy cohort in Calgary, Alberta. Maternal self-reported data on height and pre-pregnancy weight from term, singleton, cephalic pregnancies (n = 1996) were linked to clinical data on pregnancy and birth events retrieved from electronic health records. Descriptive and bivariate regression analysis were used to compare pregnancy and birth outcomes between women categorized as normal weight, overweight and obese based on the pre-pregnancy BMI. Multinomial regression analysis stratified by type of labour onset examined the association between pre-pregnancy BMI and mode of delivery controlling for maternal age, pre-existent health conditions, parity, fertility treatments, history of C-section and pregnancy complications.ResultsThe cohort consisted of 65.8% normal weight, 23.6% overweight and 10.6% obese women. Women with increased pre-pregnancy BMI were more likely to develop pregnancy complications such as preeclampsia (OR 3.5, CI 2.0-4.6 for overweight; OR 5.3, CI 3.3-8.5 for obese) and gestational diabetes (OR 3.0, CI 1.8-5.0 for overweight; OR 6.5, CI 3.7-11.2 for obese) than normal weight women. Spontaneous onset of labour was recorded in 71.2% of women with normal pre-pregnancy BMI, whereas 39.3% of overweight and 49% of obese women had their labour induced. For women with spontaneous labour, pre-pregnancy BMI was not a significant risk factor for mode of delivery, controlling for covariates. Among women with induced labor, obesity was a significant risk factor for delivery by C-section (adjusted OR 2.2; CI 1.2-4.1).ConclusionsEven among women with term, singleton pregnancies obtaining prenatal care in community-based settings, obese women who undergo labour induction are at increased risk of obstetrical interventions at delivery. These findings highlight the importance of tailored maternal care in pregnancy and at delivery of pregnant women with increased BMI in order to improve the outcomes and wellbeing of these women and their children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-014-0422-y) contains supplementary material, which is available to authorized users.

Epigenetic Analysis of Neurocognitive Development at 1 year of Age in a Community-Based Pregnancy Cohort

Multiple studies show that molecular genetic changes and epigenetic modifications affect the risk of cognitive disability or impairment. However, the role of epigenetic variation in cognitive development of neurotypical young children remains largely unknown. Using data from a prospective, community-based study of mother-infant pairs, we investigated the association of DNA methylation patterns in neonatal umbilical cord blood with cognitive and language development at 1 year of age. No CpG loci achieved genome-wide significance, although a small number of weakly suggestive associations with Bayley-III Receptive Communication scales were noted. While umbilical cord blood is a convenient resource for genetic analyses of birth outcomes, our results do not provide conclusive evidence that its use for DNA methylation profiling yields epigenetic markers that are directly related to postnatal neurocognitive outcomes at 1 year of age.

Risk of Miscarriage Among Black Women and White Women in a US Prospective Cohort Study

Many adverse pregnancy outcomes differ by race. We examined the association between self-reported race and miscarriage (pregnancy loss at <20 weeks) in a community-based pregnancy cohort. Women from the southeastern United States (North Carolina, Texas, and Tennessee) were enrolled in "Right from the Start" from 2000 to 2009. They were recruited while trying to conceive or during early pregnancy. Participants completed study ultrasound examinations, interviews, and consent forms for review of medical records. We used proportional hazard models to examine miscarriage risk among black women compared with white women, adjusted for confounders. There were 537 observed miscarriages among 4,070 women, 23% of whom self-identified as black (n = 932). The life table-adjusted cumulative risk of loss after gestational week 5 was 21.3%. With adjustment for age and alcohol use, blacks had increased risk of miscarriage compared with whites (adjusted hazard ratio = 1.57, 95% confidence interval: 1.27, 1.93). When risk of loss before gestational week 10 was dichotomized at the median gestational age, there was little difference, but black women had a greater risk thereafter compared with white women (adjusted hazard ratio = 1.93, 95% confidence interval: 1.48, 2.51). Early pregnancy ultrasound examinations did not differ by race. In summary, self-reported race is independently associated with risk of miscarriage, and the higher risk for black women is concentrated in gestational weeks 10-20.

Accuracy of reporting bleeding during pregnancy

Vaginal bleeding during pregnancy has been considered a marker of an at-risk pregnancy, but the accuracy of reported bleeding has not been assessed. We sought to evaluate the agreement in vaginal bleeding reports based on prospective daily diary and retrospective recall at first-trimester interview and to investigate predictors of reporting accuracy. Participants recruited prior to pregnancy for a community-based pregnancy cohort (n = 153) completed web-based daily diaries beginning before pregnancy until the end of the first trimester. A comprehensive first-trimester interview was conducted, and the bleeding data from diary and interview were compared. Kappa statistics were used to quantify agreement. Log-linear models were used to investigate maternal age, prior miscarriage, and current pregnancy outcome as potential predictors of agreement. We found that bleeding characteristics (number of bleeding episodes, bleeding heaviness, duration and gestational timing) from the diary and interview were reported with high levels of agreement. Kappas ranged from 0.77 to 0.84. Retrospective report of any bleeding had a sensitivity of 0.80 and specificity of 1.0; however, sensitivity was lower when examined within smaller time intervals. Important predictors of agreement were not identified in this analysis, but the sample was small. Overall, the presence of vaginal bleeding, a common and potentially alarming symptom of early pregnancy, may be assessed by interview later in pregnancy with reasonable accuracy.

Association Between First-Trimester Vaginal Bleeding and Miscarriage

To estimate the strength of association between first-trimester bleeding and miscarriage, setting aside bleeding at time of loss. Women enrolled in a community-based pregnancy cohort study before or during early pregnancy. Detailed first-trimester bleeding data were collected by telephone interview. Bleeding episodes proximal to miscarriage (within 4 days) were excluded. We used discrete-time hazard models to evaluate the association between bleeding and miscarriage. Models were adjusted for maternal age, prior miscarriage, and smoking. Exploratory regression tree analysis was used to evaluate the relative importance of other bleeding characteristics (duration, associated pain, color, timing). Of the 4,510 participants, 1,204 (27%) reported some first-trimester vaginal bleeding or spotting, and 517 miscarriages were observed. Eight percent of those with bleeding reported heavy bleeding episodes. When we evaluated any bleeding, including episodes of only spotting, the unadjusted relative odds ratio (OR) of miscarriage for women with bleeding (n=1,204) was 1.1 (95% confidence interval [CI] 0.9-1.3). However, women who reported heavy bleeding (n=97) had nearly three times the risk of miscarriage compared with women without bleeding during the first trimester (OR 3.0, 95% CI 1.9-4.6). Adjustment for covariates had little effect on estimates. Further analyses suggested that women with heavy bleeding accompanied by pain were the group accounting for most of the elevated risk. Heavy bleeding in the first trimester, particularly when accompanied by pain, is associated with higher risk of miscarriage. Spotting and light episodes are not, especially if lasting only 1-2 days. II.

Synergistic Effects of Traffic-Related Air Pollution and Exposure to Violence

ISEE-274 Objective: Disproportionate life stress and consequent physiologic alteration (ie, immune dysregulation) have been proposed as a major pathway linking socioeconomic position, environmental exposures, and health disparities. Asthma, for example, disproportionately impacts lower-income urban communities, where air pollution and social stressors may be elevated. We aimed to examine the role of exposure to violence (ETV), as a chronic stressor, in altering susceptibility to traffic-related air pollution in asthma etiology. Material and Methods: We developed GIS-based models to retrospectively estimate residential exposures to traffic-related pollution for 413 children in a community-based pregnancy cohort, recruited in East Boston, MA between 1987 and 1993, using monthly NO2 measurements for 13 sites over 18 years. We merged pollution estimates with questionnaire data on lifetime ETV and examined the effects of both on childhood asthma etiology. Results: Correcting for potential confounders, we found an elevated risk of asthma with a one standard deviation (4.3 ppb) increase in NO2 exposure solely among children with above-median ETV [OR = 1.63 (95% CI = 1.14–2.33)]. Among children always living in the same community, with lesser exposure measurement error, this association was magnified [OR = 2.40 (95% CI = 1.48–3.88)]. Of multiple exposure periods, year-of-diagnosis NO2 was most predictive of asthma outcomes. Conclusions: We found an association between traffic-related air pollution and asthma solely among urban children exposed to violence. Future studies should consider socially patterned susceptibility, common spatial distributions of social and physical environmental factors, and potential synergies among these. Prospective assessment of physical and social exposures may help determine causal pathways and critical exposure periods.