Maternal age and the size of White, Black, Hispanic, and mixed infants

Maternal Age Patterns of Preterm Birth: Exploring the Moderating Roles of Chronic Stress and Race/Ethnicity

BACKGROUND

Despite the suggested contribution of cumulative chronic stress to the racial/ethnic disparities in preterm birth (PTB), it is unclear how chronic stress, maternal age, and race/ethnicity are linked underlying PTB.

PURPOSE

We investigated the moderating effect of chronic stress on the maternal age-PTB association among non-Hispanic (N-H) White, N-H Black, Hispanic, and Asian women.

METHODS

We analyzed the Washington State's Pregnancy Risk Assessment Monitoring System data linked with birth certificates. The sample included women aged 18 years or older who birthed the first, singleton baby without birth defects. Chronic stress was measured by race/ethnicity-specific chronic stress indices. A maternal age-chronic stress interaction was modeled to predict PTB by logistic regression stratified by race/ethnicity. In subanalysis, the moderating role of racism was investigated in the maternal age-chronic stress interaction among three minority groups combined.

RESULTS

Women's maternal age trajectory of PTB varied by their race/ethnicity and chronic stress level. N-H White and N-H Black women showed a steeper maternal age-related increase in PTB (weathering) under higher chronic stress, indicating a chronic stress' cumulative effect with maternal age. Besides, the extent of weathering was amplified by racism on top of chronic stress, particularly among N-H Black women.

CONCLUSIONS

These results show that both chronic stress and racism may develop accelerated PTB risk among minority women. Future research should use more objective and accurate chronic stress measures to ascertain the complex relationships among chronic stress, racial discrimination, and maternal age underlying the racial/ethnic differentials in PTB.

The weathering hypothesis as an explanation for racial disparities in health: a systematic review

PURPOSE

The weathering hypothesis states that chronic exposure to social and economic disadvantage leads to accelerated decline in physical health outcomes and could partially explain racial disparities in a wide array of health conditions. This systematic review summarizes the literature empirically testing the weathering hypothesis and assesses the quality of the evidence regarding weathering as a determinant of racial disparities in health.

METHODS

Databases (Web of Science, Ovid MEDLINE, PubMed, and Embase) were searched for studies published in English up to July 1, 2017. Studies that tested the weathering hypothesis for any physical health outcome and included at least one socially or economically disadvantaged group (e.g., Blacks) for whom the weathering hypothesis applies were assessed for eligibility. Threats to validity were assessed using the Quality in Prognostic Studies tool.

RESULTS

The 41 included studies were rated as having overall good methodological quality. Most studies found evidence in support of the weathering hypothesis, although the magnitude of support varied by the health outcome and population studied.

CONCLUSIONS

Future evaluations of the weathering hypothesis should include an examination of additional health outcomes and interrogate mechanisms that could link weathering to poor health.

Paternal race/ethnicity and risk of adverse birth outcomes in the United States, 1989-2013

Objectives

Investigate adverse birth outcomes in the United States (US) from 1989–2013 in relation to paternal and maternal race/ethnicity.

Design

We used US natality data for singleton births to women 15–44 with information on birthweight, gestational age, and covariates (n = 90,771,339). We calculated unadjusted and adjusted probabilities of preterm birth (PTB, < 37 weeks gestation) and small for gestational age (SGA, < 10^th percentile) among all combinations of maternal and paternal race/ethnicity: non-Hispanic black (NHB), non-Hispanic white (NHW), Hispanic, and Asian, and where paternal race/ethnicity was missing.

Results

Missing, followed by NHB, paternal race/ethnicity had the two highest risks of PTB within each maternal racial/ethnic group. Asian, followed by NHW, paternal race/ethnicity had the two lowest risks of PTB. For SGA, however, Asian, followed by missing, paternal race/ethnicity had the two highest risks, and NHW race/ethnicity had the lowest risk. Our findings also demonstrate effect modification on the additive scale, with missing and NHB paternal race/ethnicity conferring a larger increase in risk of PTB for NHB women compared to women of other race/ethnicity groups.

Conclusions

These data confirm US disparities in adverse birth outcomes by maternal and paternal race/ethnicity and argue for increased resources and interventions in response.

Pre-Zika descriptive epidemiology of microcephaly in Texas, 2008-2012

BACKGROUND

There are limited population-based studies on microcephaly. We characterized the epidemiology of microcephaly in Texas during a 5-year period (2008-2012), prior to the Zika epidemic in the Western hemisphere (2015). The associations of suspected risk factors were compared across four clearly defined case groups.

METHODS

Data from the Texas Birth Defects Registry were used to calculate the prevalence of congenital microcephaly and crude and adjusted prevalence ratios using Poisson regression. Twelve maternal and infant factors were assessed across case groups, which included total (explained + unexplained), explained (e.g., syndromic), unexplained, and severe unexplained microcephaly (head circumference <3^rd percentile).

RESULTS

The birth prevalence for total and total severe microcephaly were 14.7 and 4.8 per 10,000 livebirths, respectively. For explained and unexplained cases, significantly elevated risks were noted for mothers who were older (35+), less educated (≤12 years), diabetic (pre-pregnancy or gestational), or had a preterm delivery. Unlike explained cases, however, mothers who were non-White or smoked had an increased risk for unexplained microcephaly. Furthermore, young maternal age (<20), multiparity, and higher BMI reduced the risk for unexplained microcephaly. For severe unexplained cases, the risk profile was similar to that for all unexplained cases-with the exception of null associations noted for diabetes and birth year.

CONCLUSIONS

We found that risk patterns for microcephaly varied across case groupings. Risk factors included maternal race/ethnicity, age, and smoking during pregnancy. Among severe unexplained cases, notable positive associations were seen among mothers who were non-Hispanic Black or less educated, while inverse associations were noted for obesity.

Small-for-gestational-age birth and maternal plasma antioxidant levels in mid-gestation: a nested case-control study

OBJECTIVE

To assess whether maternal plasma antioxidant levels in mid-pregnancy are associated with small-for-gestational-age (SGA) birth.

DESIGN

Case-control study nested within a population-based cohort study.

SETTING

Four hospitals in Montreal, Canada.

POPULATION

Pregnant women recruited before 24 weeks of gestation, whose pregnancies were not complicated by pre-eclampsia or preterm delivery.

METHODS

Blood samples were obtained at 24-26 weeks and assayed for nutritionally derived antioxidant levels in SGA cases (n = 324) and randomly selected controls with birthweights between the 25th and 75th centiles (n = 672). We performed logistic regression analyses using the standardised z-score of each antioxidant as the main independent variable, after summing highly correlated antioxidants or combining via principle component analysis. We adjusted for risk factors for SGA that were associated with antioxidant levels.

MAIN OUTCOME MEASURES

SGA, birthweight <10th centile for gestational age and sex.

RESULTS

Retinol was positively associated with risk of SGA (adjusted odds ratio [OR] 1.41; 95% confidence interval [95% CI] 1.22-1.63, per SD increase). Carotenoids (log of the sum of β-carotene, lutein/zeaxanthin, α- and β-cryptoxanthin) were negatively associated with SGA (adjusted OR 0.64; 95% CI 0.54-0.78, per SD increase). We found no significant associations between SGA and lycopene or any of the forms of vitamin E assessed, including α-tocopherol, corrected α-tocopherol (per nmol/l of low-density lipoprotein articles), or γ-tocopherol.

CONCLUSIONS

Elevated retinol may be associated with an increased risk of SGA, whereas elevated carotenoid levels may reduce the risk. A better understanding of the nature of these associations is required, however, before recommending specific nutritional interventions in an attempt to prevent SGA birth.

Using community-based participatory mixed methods research to understand preconception health in African American communities of Arizona

The article discusses Arizona's strategic implementation and evaluation of the first time motherhood initiative grant (FTMI) to understand preconception health among African American men and women in Arizona. Longitudinal focus groups assessed whether African American men and women in the targeted areas comprehended and recalled the messages related to preconception health. Matched pre and posttests assessed community members' knowledge of preconception as well as physicians' perceptions on preconception health and care. Focus-group data were transcribed and coded by independent coders to conduct content analyses. Inter-rater reliability and agreement among coders, bivariate and multivariate statistics were conducted for quantitative matched pre and posttests data using SAS v9.2 (SAS Institute, Cary, NC). The social marketing campaign had limited impact in recall and comprehension of the preconception health message among African American men and women. Data from focus groups revealed that African American men and women perceived preconception health to be vital. And results from the pretest and posttests of community-based presentations, further supported this finding. Evidence from Grand Round presentations indicated that practitioners and health care providers had diverging views on preconception health. Use of community-based participatory mixed methods research can facilitate better understanding of the efficacy of strategic interventions such as FTMI and can provide valuable information on preconception health. Cost limitations often prohibit extensive evaluation of social marketing campaigns, hence, evaluators and researchers should assess the feasibility of conducting an efficacy study versus an effectiveness study in evaluating social marketing campaigns.

Exploring weathering: effects of lifelong economic environment and maternal age on low birth weight, small for gestational age, and preterm birth in African-American and white women

White women experience their lowest rate of low birth weight (LBW) in their late 20s; the nadir LBW for African-American women is under 20 years with rates rising monotonically thereafter, hypothesized as due to "weathering" or deteriorating health with cumulative disadvantage. Current residential environment affects birth outcomes for all women, but little is known about the impact of early life environment. The authors linked neighborhood income to a transgenerational birth file containing infant and maternal birth data, allowing assessment of economic effects over a woman's life course. African-American women who were born in poorer neighborhoods and were still poor as mothers showed significant weathering with regard to LBW and small for gestational age (SGA) but not preterm birth (PTB). However, African-American women in upper-income areas at both time points had a steady fall in LBW and SGA rate with age, similar to the pattern seen in white women. No group of white women, even those always living in poorer neighborhoods, exhibited weathering with regard to LBW, SGA, or PTB. In contrast, the degree of weathering among African-American women is related to duration of exposure to low-income areas and disappears for those with a life residence in non-poor neighborhoods.

Prematurity and low birth weight as potential mediators of higher stillbirth risk in mixed black/white race couples

OBJECTIVE

Although births of multiracial and multiethnic infants are becoming more common in the United States, little is known about birth outcomes and risks for adverse events. We evaluated risk of fetal death for mixed race couples compared with same race couples and examined the role of prematurity and low birth weight as potential mediating risk factors.

METHODS

We performed a retrospective cohort analysis using data from the 1998-2002 California Birth Cohort to evaluate the odds of fetal death, low birth weight, and prematurity for couples with a mother and father who were categorized as either being of same or different racial groups. Risk of prematurity (birth prior to 37 weeks gestation) and low birth weight (<2500 g) were also tested to see if the model could explain variations among groups.

RESULTS

The analysis included approximately 1.6 million live births and 1749 stillbirths. In the unadjusted model, compared with two white parents, black/black and black/white couples had a significantly higher risk of fetal death. When all demographic, social, biological, genetic, congenital, and procedural risk factors except gestational age and birth weight were included, the odds ratios (OR) were all still significant. Black/black couples had the highest level of risk (OR 2.11, CI 1.77-2.51), followed by black mother/white father couples (OR 2.01, CI 1.16-3.48), and white mother/black father couples (OR 1.84, CI 1.33-2.54). Virtually all of the higher risk of fetal death was explainable by higher rates of low birth weight and prematurity.

CONCLUSIONS

Mixed race black and white couples face higher odds of prematurity and low birth weight, which appear to contribute to the substantially higher demonstrated risk for stillbirth. There are likely additional unmeasured factors that influence birth outcomes for mixed race couples.

Fetal growth among infants with congenital heart defects by maternal race/ethnicity

PURPOSE

Congenital heart defects (CHDs) are the most prevalent birth defects. Infants with CHDs more often are small-for-gestational age (SGA) than infants without CHD; however, little is known about racial/ethnic variations in prevalence of SGA or large-for-gestational age (LGA) for infants born with CHDs. This study determined the risk of SGA and LGA for non-Hispanic (NH)-black and Hispanic infants with CHDs.

METHODS

Data from the Florida Birth Defects Registry were used in a retrospective cohort study of 10,027 live-born infants to resident NH-White, NH-Black, and Hispanic women ages 15-49 years from January 1, 1998, to December 31, 2003, and diagnosed with 11 CHDs. Defect-specific odds ratios and 95% confidence intervals were computed for risk of SGA and LGA by race/ethnicity and adjusted for covariates using multinomial logistic regression.

RESULTS

After adjusting for covariates, we found there were no statistically significant racial/ethnic differences in risk of SGA. However, NH-Blacks with ventricular septal defect had increased risk of LGA and NH-Blacks with tetralogy of Fallot had decreased risk of LGA compared to NH-Whites.

CONCLUSIONS

Very few racial/ethnic differences in fetal growth are present among infants with CHD. Further elucidation of the factors involved in fetal growth and the impact of CHD itself on fetal development is needed.