Transgenerational risk for low birth weight and preterm birth: The role of biology and neighborhood factors in racial disparities

The purpose of this dissertation research is to ascertain the impact of biological factors as well as social and economic environmental factors on the risk of low birth weight (LBW) and preterm birth (PTB) among infants of non-Hispanic (NH) white and NH black mothers, under the hypothesis that intergenerational factors could be explanatory variables in the perpetuated trend in racial/ethnic disparities in birth outcomes. Three separate research studies were performed. The first is a systematic review and meta-analysis of studies reporting the association between LBW/PTB and neighborhood disadvantage, where the results demonstrate that there is a statistically significant higher odds of LBW and PTB among mothers resident in the most disadvantaged neighborhoods relative to those in the least disadvantaged neighborhoods. This relationship was found only when race-stratified, rather than race-adjusted, models were performed. The second and third studies use a transgenerational dataset of births in Allegheny County, Pennsylvania with birth records of infants born in the years 2009-2011 to mothers who were also born in the County in the years 1979-1998. The second study focuses on the role of mothers’ birth weight (MBW) along with social and economic contextual factors on infant risk of LBW; while the third study focuses on the role of mothers’ gestational age (MGA) coupled with social and economic contextual factors on infant risk of PTB. This research makes significant unique contributions to this field of public health research by examining both biological and neighborhood context factors as predictors of PTB and LBW in multivariate and multilevel models. Even more important is the novel examination of the subcategories of birth weight and gestational age, which led to results suggesting differing roles of biology and neighborhood context among these subcategories. LBW and PTB are of public health significance because they increase an infant’s risk of death in the first year of life, developmental disabilities, and chronic diseases in adulthood. The healthcare costs related to treatment of a prematurely born infant costs the United States billions of dollars a year and can be associated with billions more decades later when chronic diseases develop in adulthood

Sex-specific associations of maternal birthweight with offspring birthweight in the Omega study.

PURPOSE: We investigated nonlinear and offspring sex-specific associations of maternal birthweight (BW) with offspring BW among participants of the Omega study, a pregnancy cohort. METHODS: Maternal BW was modeled as a continuous variable, linear spline and binary variable indicating low birthweight (LBW;≥2500 grams). Offspring BW was modeled as a continuous and binary variable in regression models. Nonlinearity was assessed using likelihood ratio tests (LRTs) in marginal linear spline models. RESULTS: For every 100-gram increase of maternal BW, offspring BW increased by 22.29 (95% CI: 17.57, 27.02) or 23.41 (95% CI: 6.87, 39.96) grams among mothers with normal BW or born macrosomic, respectively, but not among LBW mothers (β = -8.61 grams; 95% CI: -22.88, 5.65; LRT P-value = .0005). For every 100-gram increase in maternal BW, BW of male offspring increased 23.47 (95% CI: 16.75, 30.19) or 25.21 (95% CI: 4.35, 46.07) grams among mothers with normal BW or born macrosomic, respectively, whereas it decreased 31.39 grams (95% CI: -51.63, -11.15) among LBW mothers (LRT P-value \u3c .0001). Corresponding increases in BW of female offspring (16-22 grams) did not differ among mothers with LBW, normal BW or macrosomia (LRT P-value = .9163). CONCLUSIONS: Maternal and offspring BW associations are evident among normal BW and macrosomic mothers. These associations differ by offspring sex

Strategies for recruitment and retention of teen mothers in a program to prevent repeat pregnancy

Background: We describe challenges to recruitment and retention of teen mothers in a study to prevent repeat teen pregnancies, and strategies used to overcome them. Methods: We documented recruitment efforts, the teens who were retained at each stage of the intervention and changes to strategies. Results: Challenges to recruitment and retention were related to lifestyles, immaturity, and competing demands, among others. Successful strategies included bus advertisements, early pairing of teens with mentors, using electronic media, convenient meeting times with a meal, providing child care, transportation vouchers and immediate incentives. Conclusions: This study highlights impediments to teen mother research recruitment and retention, and the value of emerging technologies and strong bonding relationships early in the intervention to maximize recruitment and retention

Sex-specific Associations of Maternal Birthweight with Offspring Birthweight in the Omega Study: The role of pre-pregnancy body mass index

Thesis (Master's)--University of Washington, 2016-12Background: Birth weight is an indicator of fetal growth and development, important determinants of life course health. Maternal birthweight (BW) is one of the strongest predictors of offspring BW, perpetuating generational cycles of poor health and risk for adverse birth outcomes. However, potential non-linear relationships or modifying or mediating factors of maternal and offspring BW associations have not been fully described. Objective: We examined (1) the overall maternal-offspring BW association, (2) offspring sex-specific differences in the association, as well as (3) the role of pre-pregnancy body mass index (BMI) as modifier or mediator of the association. Methods: The study was conducted among N = 3745 participants of the Omega pregnancy cohort study in Washington State (1996-2008). The exposure variable was maternal BW, modeled as a continuous variable, a linear spline with knots at 2500 grams and 4000 grams (macrosomia), and a binary variable indicating low birthweight (LBW) status (< 2500 grams vs. ≥ 2500 grams). Outcomes were offspring BW and LBW status. Linear and logistic regression models, adjusted for potential confounders, were used to estimate differences in mean offspring BW and odds of LBW, respectively, and corresponding 95% confidence intervals. Effect modification (by offspring sex or pre-pregnancy BMI) was assessed using stratified analyses and interaction terms. Mediation of associations by pre-pregnancy BMI was examined using the potential outcomes framework of causal analysis. Results: The average offspring BW in the study population was 3450.8 grams. Overall, 4.2% of the offspring had LBW. An increase in maternal BW was positively associated with offspring BW among mothers with normal BW (β =22.05 grams offspring BW per 100 grams maternal BW, 95% CI: 17.32, 26.79) or macrosomia (β =23.86 grams offspring BW per 100 grams maternal BW, 95%CI: 7.26, 40.46). LBW mothers had a two-fold higher risk of having LBW infants (OR = 1.96, 95% CI: 1.24, 3.09). Across the distribution of maternal BW we observed a non-linear slope for males (likelihood ratio test (LRT) p-value for improvement in fit by linear spline vs continuous model < 0.001) and a linear slope for females (LRT p-value = 0.9231). The relationship between maternal and offspring BW, as represented by the linear spline, differed by offspring sex (p-value for interaction = 0.0149). Mothers who were LBW and had male offspring had a statistically insignificant 1.2-fold (95% CI: 0.55, 2.72) higher risk of having a LBW infant while mothers who were LBW and had female offspring had a 2.67-fold (95% CI: 1.51, 4.75) higher risk of having a LBW infant (p-value for interaction = 0.120). In sex-specific analyses, maternal-offspring BW associations were similar among women of normal pre-pregnancy BMI or overweight/obese pre-pregnancy BMI groups. Maternal pre-pregnancy BMI mediated 2.57% (95% CI: 2.16%, 3.21%) of the associations between maternal and offspring BW, overall. However this mediation was not evident in offspring sex-specific models. Conclusion: We found that the association between maternal and offspring BW may differ by offspring sex, with a non-linear relationship among males, but not females. Pre-pregnancy BMI did not appear to modify maternal-offspring BW associations and it mediated only a small proportion of the associations. Our findings, if supported by other replication studies in diverse populations, provide a new paradigm to understand factors involved in transgenerational BW transmission and guide future investigations of potential mechanisms accounting for maternal-offspring BW associations

Antepartum and intrapartum stillbirth rates across gestation: a cross-sectional study using the revised foetal death reporting system in the U.S.

Abstract Background There is a renewed call to address preventable foetal deaths in high-income countries, especially where progress has been slow. The Centers for Disease Control and Prevention released publicly, for the first time, the initiating cause and estimated timing of foetal deaths in 2014. The objective of this study is to describe risk and characteristics of antepartum versus intrapartum stillbirths in the U.S., and frequency of pathological examination to determine cause. Methods We conducted a cross-sectional study of singleton births (24–43 weeks) using 2014 U.S. Fetal Death and Natality data available from the National Center for Health Statistics. The primary outcome was timing of death (antepartum (n = 6200), intrapartum (n = 453), and unknown (n = 5403)). Risk factors of interest included maternal sociodemographic, behavioural, medical and obstetric factors, along with foetal sex. We estimated gestational week-specific stillbirth hazard, risk factors for intrapartum versus antepartum stillbirth using multivariable log-binomial regression models, conditional probabilities of intrapartum and antepartum stillbirth at each gestational week, and frequency of pathological examination by timing of death. Results The gestational age-specific stillbirth hazard was approximately 2 per 10,000 foetus-weeks among preterm gestations and > 3 per 10,000 foetus-weeks among term gestations. Both antepartum and intrapartum stillbirth risk increased in late-term and post-term gestations. The risk of intrapartum versus antepartum stillbirth was higher among those without a prior live birth, relative to those with at least one prior live birth (RR 1.32; 95% CI 1.08–1.61) and those with gestational hypertension, relative to those with no report of gestational hypertension (RR 1.47; 95% CI 1.09–1.96), and lower among Black, relative to white, individuals (RR 0.70; 95% CI 0.55–0.89). Pathological examination was not performed/planned in 25% of known antepartum stillbirths and 29% of known intrapartum stillbirths. Conclusion These findings suggest greater stillbirth risk in the late-term and post-term periods. Primiparous mothers had greater risk of intrapartum than antepartum still birth, suggesting the need for intrapartum interventions for primiparous mothers in this phase of pregnancy to prevent some intrapartum foetal deaths. Efforts are needed to improve understanding, prevention and investigation of foetal deaths as well as improve stillbirth data quality and completeness in the United States

African American Unemployment and the Disparity in Periviable Births.

Periviable infants (i.e., born before 26 complete weeks of gestation) represent fewer than .5% of births in the US but account for 40% of infant mortality and 20% of billed hospital obstetric costs. African American women contribute about 14% of live births in the US, but these include nearly a third of the country's periviable births. Consistent with theory and with periviable births among other race/ethnicity groups, males predominate among African American periviable births in stressed populations. We test the hypothesis that the disparity in periviable male births among African American and non-Hispanic white populations responds to the African American unemployment rate because that indicator not only traces, but also contributes to, the prevalence of stress in the population. We use time-series methods that control for autocorrelation including secular trends, seasonality, and the tendency to remain elevated or depressed after high or low values. The racial disparity in male periviable birth increases by 4.45% for each percentage point increase in the unemployment rate of African Americans above its expected value. We infer that unemployment-a population stressor over which our institutions exercise considerable control-affects the disparity between African American and non-Hispanic white periviable births in the US