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Introduction: Breastfeeding has significant health benefits for infants and birthing persons, including reduced risk of chronic disease. The American Academy of Pediatrics recommends exclusively breastfeeding infants for 6 months and recently extended its recommendation for continuing to breastfeed with supplementation of solid foods from one to two years. Studies consistently identify lower breastfeeding rates among US infants, with regional and demographic variability. We examined breastfeeding in birthing person-infant pairs among healthy, term pregnancies enrolled in the New Hampshire Birth Cohort Study between 2010 and 2017 (n = 1176). Methods: Birthing persons 18–45 years old were enrolled during prenatal care visits at ~ 24–28 weeks gestation and have been followed since enrollment. Breastfeeding status was obtained from postpartum questionnaires. Birthing person and infant health and sociodemographic information was abstracted from medical records and prenatal and postpartum questionnaires. We evaluated the effects of birthing person age, education, relationship status, pre-pregnancy body mass index, gestational weight gain (GWG), smoking and parity, and infant sex, ponderal index, gestational age and delivery mode on breastfeeding initiation and duration using modified Poisson and multivariable linear regression. Results: Among healthy, term pregnancies, 96% of infants were breastfed at least once. Only 29% and 28% were exclusively breastfed at 6-months or received any breastmilk at 12-months, respectively. Higher birthing person age, education, and parity, being married, excessive GWG, and older gestational age at delivery were associated with better breastfeeding outcomes. Smoking, obesity, and cesarean delivery were negatively associated with breastfeeding outcomes. Conclusions: Given the public health importance of breastfeeding for infants and birthing persons, interventions are needed to support birthing persons to extend their breastfeeding duration. Significance: What is already known? The benefits of breastfeeding to child and birthing person health are well-documented, however, rates of breastfeeding initiation and duration continue to fall short of health-based guidelines. Regional differences exist and certain rural New England states tend to have amongst the highest breastfeeding rates in the US. What this study adds? This study of n = 1176 birthing persons-infant pairs enrolled in the New Hampshire Birth Cohort Study, a rural, general population pregnancy cohort, suggests that factors influencing breastfeeding outcomes align closely with studies conducted in urban settings and using nationally-representative surveys. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are related to various adverse health outcomes, and food is a common source of PFAS exposure. Dietary sources of PFAS have not been adequately explored among U.S. pregnant individuals. We examined associations of dietary factors during pregnancy with PFAS concentrations in maternal plasma and human milk in the New Hampshire Birth Cohort Study. PFAS concentrations, including perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorodecanoate (PFDA), were measured in maternal plasma collected at ∼28 gestational weeks and human milk collected at ∼6 postpartum weeks. Sociodemographic, lifestyle and reproductive factors were collected from prenatal questionnaires and diet from food frequency questionnaires at ∼28 gestational weeks. We used adaptive elastic net (AENET) to identify important dietary variables for PFAS concentrations. We used multivariable linear regression to assess associations of dietary variables selected by AENET models with PFAS concentrations. Models were adjusted for sociodemographic, lifestyle, and reproductive factors, as well as gestational week of blood sample collection (plasma PFAS), postpartum week of milk sample collection (milk PFAS), and enrollment year. A higher intake of fish/seafood, eggs, coffee, or white rice during pregnancy was associated with higher plasma or milk PFAS concentrations. For example, every 1 standard deviation (SD) servings/day increase in egg intake during pregnancy was associated with 4.4 % (95 % CI: 0.6, 8.4), 3.3 % (0.1, 6.7), and 10.3 % (5.6, 15.2) higher plasma PFOS, PFOA, and PFDA concentrations respectively. Similarly, every 1 SD servings/day increase in white rice intake during pregnancy was associated with 7.5 % (95 % CI: -0.2, 15.8) and 12.4 % (4.8, 20.5) greater milk PFOS and PFOA concentrations, respectively. Our study suggests that certain dietary factors during pregnancy may contribute to higher PFAS concentrations in maternal plasma and human milk, which could inform interventions to reduce PFAS exposure for both birthing people and offspring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Prior studies suggest that prenatal per- and polyfluoroalkyl substances (PFAS) exposures are associated with shorter breastfeeding duration. Studies assessing PFAS mixtures and populations in North America are sparse., Methods: We quantified PFAS concentrations in maternal plasma collected during pregnancy in the New Hampshire Birth Cohort Study (2010-2017). Participants completed standardized breastfeeding surveys at regular intervals until weaning (n = 813). We estimated associations between mixtures of 5 PFAS and risk of stopping exclusive breastfeeding before 6 months or any breastfeeding before 12 months using probit Bayesian kernel machine regression. For individual PFAS, we calculated the relative risk and hazard ratio (HR) of stopping breastfeeding using modified Poisson regression and accelerated failure time models respectively., Results: PFAS mixtures were associated with stopping exclusive breastfeeding before 6 months, primarily driven by perfluorooctanoate (PFOA). We observed statistically significant trends in the association of perfluorohexane sulfonate (PFHxS), PFOA, and perfluorononanoate (PFNA) (p-trends≤0.02) with stopping exclusive breastfeeding. Participants in the highest PFOA quartile had a 28% higher risk of stopping exclusive breastfeeding before 6 months compared to those in the lowest quartile (95% Confidence Interval: 1.04, 1.56). Similar trends were observed for PFHxS and PFNA with exclusive breastfeeding (p-trends≤0.05). PFAS were not associated with stopping any breastfeeding before 12 months., Conclusions: In this cohort, we observed that participants with greater overall plasma PFAS concentrations had greater risk of stopping exclusive breastfeeding before 6 months and associations were driven largely by PFOA. These findings further support the growing literature indicating that PFAS may be associated with shorter duration of breastfeeding., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

We aimed to investigate the joint, class-specific, and individual impacts of (i) PFAS, (ii) toxic metals and metalloids (referred to collectively as "metals"), and (iii) essential elements on birth outcomes in a prospective pregnancy cohort using both established and recent mixture modeling approaches. Participants included 537 mother-child pairs from the New Hampshire Birth Cohort Study. Concentrations of 6 metals and 5 PFAS were measured in maternal toenail clippings and plasma, respectively. Birth weight, birth length, and head circumference at birth were abstracted from medical records. Joint, index-wise, and individual associations of the metals and PFAS concentrations with birth outcomes were evaluated using Bayesian Kernel Machine Regression (BKMR) and Bayesian Multiple Index Models (BMIM). After controlling for potential confounders, the metals-PFAS mixture was associated with a larger head circumference at birth, which was driven by manganese. When using BKMR, the difference in the head circumference z-score when changing manganese from its 25th to 75th percentiles while holding all other mixture components at their medians was 0.22 standard deviations (95% posterior credible interval [CI]: -0.02, 0.46). When using BMIM, the posterior mean of index weight estimates assigned to manganese for head circumference z-score was 0.72 (95% CI: 0, 0.99). Prenatal exposure to the metals-PFAS mixture was not associated with birth weight or birth length by either BKMR or BMIM. Using both traditional and new mixture modeling approaches, prenatal exposure to manganese was associated with a larger head circumference at birth after accounting for exposure to PFAS and multiple toxic and essential metals., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: National Institutes of Health, National Institute of Environmental Health Sciences, National Institute of General Medical Sciences, and United States Environmental Protection Agency. Dr. McGee reports financial support was provided by Natural Sciences and Engineering Research Council of Canada. Dr. Howe reports financial support was provided by National Institute of Environmental Health Sciences. Dr. Romano reports financial support was provided by National Institute of Environmental Health Sciences., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent endocrine-disrupting chemicals associated with long-term health outcomes. PFAS are transferred from maternal blood to human milk, an important exposure source for infants, and understanding of this transfer is evolving. We characterized concentrations of 10 PFAS in human milk ( n = 426) and compared milk-to-plasma concentrations of 9 PFAS among a subset of women with paired samples ( n = 294) from the New Hampshire Birth Cohort Study using liquid chromatography-isotope dilution tandem mass spectrometry. We examined the relationship between perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in plasma versus milk and fit linear regression models to assess relationships between milk PFOA and PFOS and participant characteristics. The median plasma PFOA concentration was 0.94 ng/mL (interquartile range, IQR, 0.59-1.34) and that of PFOS was 2.60 ng/mL (IQR 1.80-3.90); the median milk PFOA concentration was 0.017 ng/mL (IQR 0.012-0.027) and that of PFOS was 0.024 ng/mL (IQR 0.016-0.036). PFOA and PFOS plasma and milk concentrations showed correlations of ρ = 0.83 and 0.77, respectively ( p < 0.001). Parity, previous lactation, week of milk collection, and body mass index were inversely associated with milk PFAS. We estimate that even among our general population cohort, some infants (∼6.5%) are exposed to amounts of PFAS via milk that may have long-term health impacts.

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent, potential metabolic disruptors of concern for infants. Mothers participating in the New Hampshire Birth Cohort Study (NHBCS) provided a plasma sample during pregnancy to measure concentrations of seven PFAS, and infant weight and length were abstracted from well-child visits between birth and 12 months. Sex-specific growth patterns of child body mass index (BMI) were fit using a growth mixture model (GMM) and the relative risk ratios (RRR) and 95% Confidence Intervals (95% CI) for the association of maternal plasma PFAS with BMI growth patterns during infancy were estimated by using multinomial logistic model for the group probabilities in the GMM. Four growth patterns were identified: Group 1) a steep increase in BMI during the first 6 months, then a leveling off; Group 2) a gradual increase in BMI across the year; Group 3) a steep increase in BMI during months 1-3, then stable BMI; and Group 4) a gradual increase in BMI with plateau around 3 months (reference group). For boys, higher maternal pregnancy perfluorooctanoate concentrations were associated with a 60% decreased chance of being in group 3 as compared to group 4, after adjusting for potential confounding variables (RRR = 0.4; 95% CI: 0.1, 0.9). For girls, higher maternal perfluorooctane sulfonate (PFOS) concentrations during pregnancy were associated with a higher likelihood of following the growth pattern of groups 2 (RRR = 2.5; 95% CI: 1.0, 6.1) and 3 (RRR = 2.8; 95% CI: 1.0, 7.6) as compared to group 4, adjusting for potential confounding variables. In this cohort, sex-specific associations of maternal plasma PFAS concentrations during pregnancy with growth patterns during the first year of life were observed, with greater BMI growth observed among infant girls born to mothers with higher pregnancy concentrations of PFOS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Silicone wristbands can assess multipollutant exposures in a non-invasive and minimally burdensome manner, which may be suitable for use among pregnant women. We investigated silicone wristbands as passive environmental samplers in the New Hampshire Birth Cohort Study, a prospective pregnancy cohort. We used wristbands to assess exposure to a broad range of organic chemicals, identified multipollutant exposure profiles using self-organizing maps (SOMs), and assessed temporal consistency and determinants of exposures during pregnancy. Participants ( n = 255) wore wristbands for 1 week at 12 gestational weeks. Of 1,530 chemicals assayed, 199 were detected in at least one wristband and 16 were detected in >60% of wristbands. A median of 23 (range: 12,37) chemicals were detected in each wristband, and chemicals in commerce and personal care products were most frequently detected. A subset of participants ( n =20) wore a second wristband at 24 gestational weeks, and concentrations of frequently detected chemicals were moderately correlated between time points (median intraclass correlation: 0.22; range: 0.00,0.69). Women with higher educational attainment had fewer chemicals detected in their wristbands and the total number of chemicals detected varied seasonally. Triphenyl phosphate concentrations were positively associated with nail polish use, and benzophenone concentrations were highest in summer. No clear associations were observed with other a priori relations, including certain behaviors, season, and socioeconomic factors. SOM analyses revealed 12 profiles, ranging from 2 to 149 participants, captured multipollutant exposure profiles observed in this cohort. The most common profile ( n = 149) indicated that 58% of participants experienced relatively low exposures to frequently detected chemicals. Less common ( n ≥ 10) and rare ( n < 10) profiles were characterized by low to moderate exposures to most chemicals and very high and/or very low exposure to a subset of chemicals. Certain covariates varied across SOM profile membership; for example, relative to women in the most common profile who had low exposures to most chemicals, women in the profile with elevated exposure to galaxolide and benzyl benzoate were younger, more likely to be single, and more likely to report nail polish use. Our study illustrates the utility of silicone wristbands for measurement of multipollutant exposures in sensitive populations, including pregnant women., (Copyright © 2020 Doherty, Pearce, Anderson, Karagas and Romano.)

Background: Exposure to cadmium may contribute to the risk of gestational diabetes mellitus (GDM) and glucose intolerance during pregnancy., Methods: We examined 917 women enrolled from 2009 to 2017 in the New Hampshire Birth Cohort Study. Lifestyle, diet, demographic factors and pregnancy outcomes were collected by questionnaire and medical record review. Cadmium concentrations were measured in urine samples collected at 24-28 weeks gestation. Women were classified as normal (n = 815), glucose intolerant (n = 86), or GDM (n = 16) based on clinical data (i.e., glucose challenge test, oral glucose challenge test). We calculated odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential confounders, using multinomial logistic regression to examine disease severity (normal, glucose intolerant, GDM) and logistic regression to examine the combined outcome of gestational hyperglycemia., Results: Little to no association was observed for glucose intolerance (OR = 1.11, 95%CI 0.85-1.45) or GDM (OR = 0.86, 95% CI 0.51-1.44) with a doubling of urinary cadmium as compared to normal women. The combined outcome of gestational hyperglycemia yielded similar results (OR = 1.07, 95% CI 0.84-1.35). However, when stratified by pre-pregnancy body mass index (BMI), there was a slight association with the combined outcome in normal weight women (OR = 1.32, 95% CI 0.88-1.98) and no association in the overweight or obese women. This positive association remained in restricted analyses of only women with no exposure to smoking during pregnancy and those who had never smoked., Conclusions: Cadmium exposure was suggestively associated with increased risk of gestational hyperglycemia among women not already at increased risk of GDM due to being overweight or obese; however, associations of cadmium with gestational hyperglycemia were not statistically significant., (Copyright © 2019 Elsevier Inc. All rights reserved.)