Interpregnancy Interval and Birth Outcomes: A Propensity Matching Study in the California Population

Maternal and Child Health Journal - Previous studies that used traditional multivariable and sibling matched analyses to investigate interpregnancy interval (IPI) and birth outcomes have reached...     

Residential Proximity to Methyl Bromide Use and Birth Outcomes in an Agricultural Population in California

Background: Methyl bromide, a fungicide often used in strawberry cultivation, is of concern for residents who live near agricultural applications because of its toxicity and potential for drift. Little is known about the effects of methyl bromide exposure during pregnancy.Objective: We investigated the relationship between residential proximity to methyl bromide use and birth outcomes.Methods: Participants were from the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study (n = 442), a longitudinal cohort study examining the health effects of environmental exposures on pregnant women and their children in an agricultural community in northern California. Using data from the California Pesticide Use Reporting system, we employed a geographic information system to estimate the amount of methyl bromide applied within 5 km of a woman’s residence during pregnancy. Multiple linear regression models were used to estimate associations between trimester-specific proximity to use and birth weight, length, head circumference, and gestational age.Results: High methyl bromide use (vs. no use) within 5 km of the home during the second trimester was negatively associated with birth weight (β = –113.1 g; CI: –218.1, –8.1), birth length (β = –0.85 cm; CI: –1.44, –0.27), and head circumference (β = –0.33 cm; CI: –0.67, 0.01). These outcomes were also associated with moderate methyl bromide use during the second trimester. Negative associations with fetal growth parameters were stronger when larger (5 km and 8 km) versus smaller (1 km and 3 km) buffer zones were used to estimate exposure.Conclusions: Residential proximity to methyl bromide use during the second trimester was associated with markers of restricted fetal growth in our study.     

Prepregnancy Obesity and Birth Outcomes

Objective To investigate the association between prepregnancy obesity and birth outcomes using fixed effect models comparing siblings from the same mother. Methods A total of 7496 births to 3990 mothers from the National Longitudinal Survey of Youth 1979 survey are examined. Outcomes include macrosomia, gestational length, incidence of low birthweight, preterm birth, large and small for gestational age (LGA, SGA), c-section, infant doctor visits, mother’s and infant’s days in hospital post-partum, whether the mother breastfed, and duration of breastfeeding. Association of outcomes with maternal pre-pregnancy obesity was examined using Ordinary Least Squares (OLS) regression to compare across mothers and fixed effects to compare within families. Results In fixed effect models we find no statistically significant association between most outcomes and prepregnancy obesity with the exception of LGA, SGA, low birth weight, and preterm birth. We find that prepregnancy obesity is associated with a with lower risk of low birthweight, SGA, and preterm birth but controlling for prepregnancy obesity, increases in GWG lead to increased risk of LGA. Conclusions Contrary to previous studies, which have found that maternal obesity increases the risk of c-section, macrosomia, and LGA, while decreasing the probability of breastfeeding, our sibling comparison models reveal no such association. In fact, our results suggest a protective effect of obesity in that women who are obese prepregnancy have longer gestation lengths, and are less likely to give birth to a preterm or low birthweight infant.     

Multiple Deliveries in North Carolina: Effects on Birth Outcomes

Objectives: The purpose of this study is to examine the trends in multiple deliveries in North Carolina and assess their effect on the rates of low birth weight, fetal mortality, and infant mortality. Methods: Using North Carolina vital statistics files, trends in multiple births, categorized by race, maternal age, and birth weight, were examined for the period 1980–1997. A partitioning method was used to estimate the contribution of maternal age distribution and age-specific multiple birth rates to the overall increase in multiple births, and the contribution of the changing multiple birth rate to observed trends in low birth weight and fetal and infant mortality. Results: Between 1980 and 1997, the state's multiple birth rate increased by 40%. Most of the increase was due to a rise in the age-specific multiple birth rates, rather than a shift in the maternal age distribution. The increase in the multiple birth rate accounted for a substantial proportion of the increase in low birth weight among Whites and Blacks. The rise in multiple births also hindered further declines in fetal and infant mortality during this time. Conclusions: Multiple births are an increasingly important contributor to perinatal outcomes, and warrant greater consideration in research aimed at evaluating trends in low birth weight and infant mortality.     

Birth defects monitoring in California: a resource for epidemiological research

Summary. The California Birth Defects Monitoring Program maintains a population-based birth defects registry of structural congenital malformations, monitoring over 600000 resident births annually. Cases are actively ascertained from hospitals and genetic centres throughout California and from selected facilities in adjacent states. Field staff identify presumptive cases from careful review of medical records. Diagnostic and demographic information is collected from in-patient and genetic centre medical charts for children diagnosed with major structural malformations between conception and 1 year of age. The application of these data to epidemiological investigations of birth defects is described in the context of prevalence studies, aetiological studies and evaluative studies, and the strengths and limitations of the registry data are discussed.     

Not at all so hard-to-reach: same-sex attracted men in Dar es Salaam

Based on research in Tanzania, this paper critically examines the widely circulating notion that African same-sex attracted men are hard-to-reach individuals and populations. Despite expectations to the contrary, it was neither time consuming nor difficult to identify and get to know same-sex attracted men in Dar es Salaam. On the contrary, a large and diverse group of such men could readily be encountered, befriended and involved in HIV-related research. The fieldwork was characterised by communicative openness and the researcher was treated with immense kindliness, hospitality and inclusivity. While we may not be in a position to say that the situation is identical everywhere else, we find reason to caution against accepting and propagating unexplained, unexamined and unverified claims to the effect that same-sex attracted men in Africa cannot be reached. We argue that such claims contribute to stigmatise same-sex attracted men and to hinder much-needed HIV-related research and programming.     

Not at all so hard-to-reach: same-sex attracted men in Dar es Salaam

Based on research in Tanzania, this paper critically examines the widely circulating notion that African same-sex attracted men are hard-to-reach individuals and populations. Despite expectations to the contrary, it was neither time consuming nor difficult to identify and get to know same-sex attracted men in Dar es Salaam. On the contrary, a large and diverse group of such men could readily be encountered, befriended and involved in HIV-related research. The fieldwork was characterised by communicative openness and the researcher was treated with immense kindliness, hospitality and inclusivity. While we may not be in a position to say that the situation is identical everywhere else, we find reason to caution against accepting and propagating unexplained, unexamined and unverified claims to the effect that same-sex attracted men in Africa cannot be reached. We argue that such claims contribute to stigmatise same-sex attracted men and to hinder much-needed HIV-related research and programming.     

Birth defects monitoring in California: a resource for epidemiological research.

The California Birth Defects Monitoring Program maintains a population-based birth defects registry of structural congenital malformations, monitoring over 600,000 resident births annually. Cases are actively ascertained from hospitals and genetic centres throughout California and from selected facilities in adjacent states. Field staff identify presumptive cases from careful review of medical records. Diagnostic and demographic information is collected from in-patient and genetic centre medical charts for children diagnosed with major structural malformations between conception and 1 year of age. The application of these data to epidemiological investigations of birth defects is described in the context of prevalence studies, aetiological studies and evaluative studies, and the strengths and limitations of the registry data are discussed.     

Neighborhood Gun Violence and Birth Outcomes in Chicago

Objectives

To examine the association between gun violence and birth outcomes among women in Chicago.

Methods

Using a 5-year set of birth files (2011–2015) merged with census and police data, birth outcomes including low birth weight (LBW, BW < 2500 g), preterm birth (PTB, < 37 weeks gestation), and small-for-gestational-age (SGA, BW < 10th percentile) were examined among non-Hispanic (NH) white, NH black, and Hispanic women in Chicago. Gun violence rates were categorized into tertiles. Multilevel, multiple logistic regression examined the effects of gun violence and race/ethnicity on birth outcomes.

Results

Of 175,065 births, 10.6% of LBW, 10.6% of PTB, and 9.1% of SGA occurred in high violence tertile. Using white women in low violence tertile as reference, the OR for LBW among black women ranged 1.9–2.1 across all tertiles, and 0.8–1.2 among Hispanic women. OR for PTB for black women were 1.6–1.7 and 1.0–1.2 for Hispanic women, and OR for SGA for black women were 1.6–1.7 and for Hispanic women 0.9–1.0.

Conclusions for Practice

In Chicago, race/ethnicity was associated with birth outcomes, regardless of the level of exposure to gun violence, in 2011–2015. The differences in racial/ethnic composition across the violence exposure levels suggest that, rather than gun violence alone, residential segregation and the geographic inequities likely contribute to disparate birth outcomes.