DOHaD at the intersection of maternal immune activation and maternal metabolic stress: a scoping review

Prenatal influences on postnatal neuroplasticity: Integrating DOHaD and sensitive/critical period frameworks to understand biological embedding in early development

Early environments can have significant and lasting effects on brain, body, and behavior across the lifecourse. Here, we address current research efforts to understand how experiences impact neurodevelopment with a new perspective integrating two well-known conceptual frameworks - the Developmental Origins of Health and Disease (DOHaD) and sensitive/critical period frameworks. Specifically, we consider how prenatal experiences characterized in the DOHaD model impact two key neurobiological mechanisms of sensitive/critical periods for adapting to and learning from the postnatal environment. We draw from both animal and human research to summarize the current state of knowledge on how particular prenatal substance exposures (psychoactive substances and heavy metals) and nutritional profiles (protein-energy malnutrition and iron deficiency) each differentially impact brain circuits' excitation/GABAergic inhibition balance and myelination. Finally, we highlight new research directions that emerge from this integrated framework, including testing how prenatal environments alter sensitive/critical period timing and learning and identifying potential promotional/buffering prenatal exposures to impact postnatal sensitive/critical periods. We hope this integrative framework considering prenatal influences on postnatal neuroplasticity will stimulate new research to understand how early environments have lasting consequences on our brains, behavior, and health.

Interdisciplinary fetal-neonatal neurology training applies neural exposome perspectives to neurology principles and practice

An interdisciplinary fetal-neonatal neurology (FNN) program over the first 1,000 days teaches perspectives of the neural exposome that are applicable across the life span. This curriculum strengthens neonatal neurocritical care, pediatric, and adult neurology training objectives. Teaching at maternal-pediatric hospital centers optimally merges reproductive, pregnancy, and pediatric approaches to healthcare. Phenotype-genotype expressions of health or disease pathways represent a dynamic neural exposome over developmental time. The science of uncertainty applied to FNN training re-enforces the importance of shared clinical decisions that minimize bias and reduce cognitive errors. Trainees select mentoring committee participants that will maximize their learning experiences. Standardized questions and oral presentations monitor educational progress. Master or doctoral defense preparation and competitive research funding can be goals for specific individuals. FNN principles applied to practice offer an understanding of gene-environment interactions that recognizes the effects of reproductive health on the maternal-placental-fetal triad, neonate, child, and adult. Pre-conception and prenatal adversities potentially diminish life-course brain health. Endogenous and exogenous toxic stressor interplay (TSI) alters the neural exposome through maladaptive developmental neuroplasticity. Developmental disorders and epilepsy are primarily expressed during the first 1,000 days. Communicable and noncommunicable illnesses continue to interact with the neural exposome to express diverse neurologic disorders across the lifespan, particularly during the critical/sensitive time periods of adolescence and reproductive senescence. Anomalous or destructive fetal neuropathologic lesions change clinical expressions across this developmental-aging continuum. An integrated understanding of reproductive, pregnancy, placental, neonatal, childhood, and adult exposome effects offers a life-course perspective of the neural exposome. Exosome research promises improved disease monitoring and drug delivery starting during pregnancy. Developmental origins of health and disease principles applied to FNN practice anticipate neurologic diagnoses with interventions that can benefit successive generations. Addressing health care disparities in the Global South and high-income country medical deserts require constructive dialogue among stakeholders to achieve medical equity. Population health policies require a brain capital strategy that reduces the global burden of neurologic diseases by applying FNN principles and practice. This integrative neurologic care approach will prolong survival with an improved quality of life for persons across the lifespan confronted with neurological disorders.

Prevalence of Fetal Inflammatory Response Syndrome and Villitis of Unknown Etiology in the Placenta of Saudi Women and Their Association with Baby Sex

Long-term health consequences are influenced by circumstances that occur during pregnancy. The convergence of the maternal and fetal circulations occurs in the placenta, which is the first organ to develop. Placental pathology provides an accurate diagnosis of amniotic sac inflammation, and pathological alterations in preterm placentas provide evidence for the causes of numerous perinatal pathologies, including spontaneous preterm births. This retrospective study aimed to re-examine placentas regarded as normal by the Obstetrics and Gynecology Department at our institution. Thirty-seven male and forty-seven female placentas were collected following full-term delivery, and the grading and staging of any evident inflammatory responses were evaluated and correlated with the babies' sex. Full-thickness placental samples that were considered normal and not sent to the histopathology department were obtained from the central and marginal regions of placental discs. Morphological examination of the fresh placenta was conducted, and fetal and maternal inflammatory response syndromes were assessed. In addition, placental villitis of unknown etiology (VUE) and chronic deciduitis were evaluated. Immunohistochemistry was performed to evaluate the patterns of inflammation in the placenta using anti-CD8 and anti-CD68 antibodies. The correlation between silent pathologies and clinical complications or the development of fetal inflammatory response syndrome was measured. In this study, 17 (20%) maternal and 10 (12%) fetal samples showed inflammatory responses. The frequencies of chronic deciduitis and VUE were higher among pregnant Saudi women than previously reported, probably because fetal inflammatory response syndrome goes unnoticed in Saudi Arabia. In addition, the prevalence of fetal and maternal inflammatory responses was higher in the placentas of the mothers of males than in those of females, suggesting that differences occur in the inflammatory response in the placenta depending on the sex of the newborn. Grading placental inflammation (in cases of VUE) typically predicts the degree of maternal anti-fetal cellular rejection; therefore, increasing the number of placental samples sent for microscopic inspection may be preferable because of their significance in identifying the causes of chronic disorders.

Maternal immune activation and role of placenta in the prenatal programming of neurodevelopmental disorders

Maternal infection during pregnancy, leading to maternal immune activation (mIA) and cytokine release, increases the offspring risk of developing a variety of neurodevelopmental disorders (NDDs), including schizophrenia. Animal models have provided evidence to support these mechanistic links, with placental inflammatory responses and dysregulation of placental function implicated. This leads to changes in fetal brain cytokine balance and altered epigenetic regulation of key neurodevelopmental pathways. The prenatal timing of such mIA-evoked changes, and the accompanying fetal developmental responses to an altered in utero environment, will determine the scope of the impacts on neurodevelopmental processes. Such dysregulation can impart enduring neuropathological changes, which manifest subsequently in the postnatal period as altered neurodevelopmental behaviours in the offspring. Hence, elucidation of the functional changes that occur at the molecular level in the placenta is vital in improving our understanding of the mechanisms that underlie the pathogenesis of NDDs. This has notable relevance to the recent COVID-19 pandemic, where inflammatory responses in the placenta to SARS-CoV-2 infection during pregnancy and NDDs in early childhood have been reported. This review presents an integrated overview of these collective topics and describes the possible contribution of prenatal programming through placental effects as an underlying mechanism that links to NDD risk, underpinned by altered epigenetic regulation of neurodevelopmental pathways.

The association between maternal stature and adverse birth outcomes and the modifying effect of race and ethnicity: a population-based retrospective cohort study

BACKGROUND

There are known differences in the risk of perinatal and maternal birth outcomes because of maternal factors, such as body mass index and maternal race. However, the association of maternal height with adverse birth outcomes and the potential differences in this relationship by race and ethnicity have been understudied.

OBJECTIVE

This study aimed to examine the association between maternal stature and adverse perinatal outcomes and the potential modification of the association by race and ethnicity.

STUDY DESIGN

This retrospective cohort study was conducted using data on all singleton births in the United States in 2016 and 2017 (N=7,361,713) obtained from the National Center for Health Statistics. Short and tall stature were defined as <10th and >90th percentiles of the maternal height distribution (<154.9 and >172.7 cm, respectively). Race and ethnicity categories included non-Hispanic White, non-Hispanic Black, American Indian or Alaskan Native Asian or Pacific Islander, and Hispanic. The primary outcomes were preterm birth (<37 weeks of gestation), perinatal death, and composite perinatal death or severe neonatal morbidity. Logistic regression was used to obtain adjusted odds ratios and 95% confidence intervals with adjustment for confounding by maternal age, body mass index, and other factors. Multiplicative and additive effect modifications by race and ethnicity were assessed.

RESULTS

The study population included 7,361,713 women with a singleton stillbirth or live birth. Short women had an increased risk of adverse outcomes, whereas tall women had a decreased risk relative to average-stature women. Short women had an increased risk of perinatal death and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 1.14 [95% confidence interval, 1.10-1.17] and 1.21 [95% confidence interval, 1.19-1.23], respectively). The association between short stature and perinatal death was attenuated in non-Hispanic Black women compared with non-Hispanic White women (adjusted odds ratio, 1.10 [95% confidence interval, 1.03-1.17] vs 1.26 [95% confidence interval, 1.19-1.33]). Compared with average-stature women, tall non-Hispanic White women had lower rates of preterm birth, perinatal death, and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 0.82 [95% confidence interval, 0.81-0.83], 0.95 [95% confidence interval, 0.91-1.00], and 0.90 [95% confidence interval, 0.88-0.93], respectively). The association between tall and average stature with perinatal death was reversed in Hispanic women (adjusted odds ratio, 1.27; 95% confidence interval, 1.12-1.44). Compared with average-stature women, all tall women had lower rates of preterm birth, particularly among non-Hispanic Black and Hispanic women.

CONCLUSION

Relative to average-stature women, short women have an increased risk of adverse perinatal outcomes across all race and ethnicity groups; these associations were attenuated in Hispanic women and for some adverse outcomes in non-Hispanic Black and Asian women. Tall mothers have a lower risk of preterm birth in all racial and ethnic groups, whereas tall non-Hispanic White mothers have a lower risk of perinatal death or severe neonatal morbidity compared with average-stature women.

Association of Birth During the COVID-19 Pandemic With Neurodevelopmental Status at 6 Months in Infants With and Without In Utero Exposure to Maternal SARS-CoV-2 Infection

IMPORTANCE

Associations between in utero exposure to maternal SARS-CoV-2 infection and neurodevelopment are speculated, but currently unknown.

OBJECTIVE

To examine the associations between maternal SARS-CoV-2 infection during pregnancy, being born during the COVID-19 pandemic regardless of maternal SARS-CoV-2 status, and neurodevelopment at age 6 months.

DESIGN, SETTING, AND PARTICIPANTS

A cohort of infants exposed to maternal SARS-CoV-2 infection during pregnancy and unexposed controls was enrolled in the COVID-19 Mother Baby Outcomes Initiative at Columbia University Irving Medical Center in New York City. All women who delivered at Columbia University Irving Medical Center with a SARS-CoV-2 infection during pregnancy were approached. Women with unexposed infants were approached based on similar gestational age at birth, date of birth, sex, and mode of delivery. Neurodevelopment was assessed using the Ages & Stages Questionnaire, 3rd Edition (ASQ-3) at age 6 months. A historical cohort of infants born before the pandemic who had completed the 6-month ASQ-3 were included in secondary analyses.

EXPOSURES

Maternal SARS-CoV-2 infection during pregnancy and birth during the COVID-19 pandemic.

MAIN OUTCOMES AND MEASURES

Outcomes were scores on the 5 ASQ-3 subdomains, with the hypothesis that maternal SARS-CoV-2 infection during pregnancy would be associated with decrements in social and motor development at age 6 months.

RESULTS

Of 1706 women approached, 596 enrolled; 385 women were invited to a 6-month assessment, of whom 272 (70.6%) completed the ASQ-3. Data were available for 255 infants enrolled in the COVID-19 Mother Baby Outcomes Initiative (114 in utero exposed, 141 unexposed to SARS-CoV-2; median maternal age at delivery, 32.0 [IQR, 19.0-45.0] years). Data were also available from a historical cohort of 62 infants born before the pandemic. In utero exposure to maternal SARS-CoV-2 infection was not associated with significant differences on any ASQ-3 subdomain, regardless of infection timing or severity. However, compared with the historical cohort, infants born during the pandemic had significantly lower scores on gross motor (mean difference, -5.63; 95% CI, -8.75 to -2.51; F1,267 = 12.63; P<.005), fine motor (mean difference, -6.61; 95% CI, -10.00 to -3.21; F1,267 = 14.71; P < .005), and personal-social (mean difference, -3.71; 95% CI, -6.61 to -0.82; F1,267 = 6.37; P<.05) subdomains in fully adjusted models.

CONCLUSIONS AND RELEVANCE

In this study, birth during the pandemic, but not in utero exposure to maternal SARS-CoV-2 infection, was associated with differences in neurodevelopment at age 6 months. These early findings support the need for long-term monitoring of children born during the COVID-19 pandemic.

DNA methylation mediates a randomized controlled trial home-visiting intervention during pregnancy and the Bayley infant's cognitive scores at 12 months of age

The crosstalk between maternal stress exposure and fetal development may be mediated by epigenetic mechanisms, including DNA methylation (DNAm). To address this matter, we collect 32 cord blood samples from low-income Brazilian pregnant adolescents participants of a pilot randomized clinical intervention study (ClinicalTrials.gov, Identifier: NCT02807818). We hypothesized that the association between the intervention and infant neurodevelopmental outcomes at 12 months of age would be mediated by DNAm. First, we searched genome methylation differences between cases and controls using different approaches, as well as differences in age acceleration (AA), represented by the difference of methylation age and birth age. According to an adjusted p-value ≤ 0.05 we identified 3090 differentially methylated positions- CpG sites (DMPs), 21 differentially methylated regions (DMRs) and one comethylated module weakly preserved between groups. The intervention group presented a smaller AA compared to the control group (p = 0.025). A logistic regression controlled by sex and with gestational age indicated a coefficient of -0.35 towards intervention group (p = 0.016) considering AA. A higher cognitive domain score from Bayley III scale was observed in the intervention group at 12 months of age. Then, we performed a potential causal mediation analysis selecting only DMPs highly associated with the cognitive domain (adj. R2 > 0.4), DMRs and CpGs of hub genes from the weakly preserved comethylated module and epigenetic clock as raw values. DMPs in STXBP6, and PF4 DMR, mediated the association between the maternal intervention and the cognitive domain at 12 months of age. In conclusion, DNAm in different sites and regions mediated the association between intervention and cognitive outcome.

Maternal COVID-19 Vaccination and Its Potential Impact on Fetal and Neonatal Development

Vaccines have been developed at "warp speed" to combat the COVID-19 pandemic caused by the SARS-CoV-2 coronavirus. Although they are considered the best approach for preventing mortality, when assessing the safety of these vaccines, pregnant women have not been included in clinical trials. Thus, vaccine safety for this demographic, as well as for the developing fetus and neonate, remains to be determined. A global effort has been underway to encourage pregnant women to get vaccinated despite the uncertain risk posed to them and their offspring. Given this, post-hoc data collection, potentially for years, will be required to determine the outcomes of COVID-19 and vaccination on the next generation. Most COVID-19 vaccine reactions include injection site erythema, pain, swelling, fatigue, headache, fever and lymphadenopathy, which may be sufficient to affect fetal/neonatal development. In this review, we have explored components of the first-generation viral vector and mRNA COVID-19 vaccines that are believed to contribute to adverse reactions and which may negatively impact fetal and neonatal development. We have followed this with a discussion of the potential for using an ovine model to explore the long-term outcomes of COVID-19 vaccination during the prenatal and neonatal periods.

Maternal Immune Activation Hypotheses for Human Neurodevelopment: Some Outstanding Questions

The Maternal Immune Activation (MIA) hypothesis is a leading model for understanding prenatal influences on individual differences in, and clinical syndromes of, neurodevelopment. Experimental animal and human research has proliferated in recent years, and there is now a sizable research base. Several meta-analyses demonstrate general support for an association between prenatal immune activation and neurodevelopment in human research. However, questions remain about the nature of the immune activation, the network of underlying mechanisms involved, and the breadth of impact across behavioral phenotypes. Complementing recent reviews of results, the current review places particular emphasis on how advances in understanding mechanisms may be improved with greater attention to addressing the methodological variation and limitations of existing studies, and identifies areas for further clinical research.

Perinatal Exposure to Phthalates: From Endocrine to Neurodevelopment Effects

Phthalates, as other endocrine disrupting chemicals (EDCs), may alter the homeostasis and the action of hormones and signaling molecules, causing adverse health outcomes. This is true especially for infants, who are both more exposed and sensitive to their effects. Phthalates are particularly harmful when the exposure occurs during certain critical temporal windows of the development, such as the prenatal and the early postnatal phases. Phthalates may also interfere with the neuroendocrine systems (e.g., thyroid hormone signaling or metabolism), causing disruption of neuronal differentiation and maturation, increasing the risk of behavioral and cognitive disorders (ADHD and autistic behaviors, reduced mental, psychomotor, and IQ development, and emotional problems). Despite more studies being needed to better understand the role of these substances, plenty of evidence suggests the impact of phthalates on the neuroendocrine system development and function. This review aims to update the knowledge on the neuroendocrine consequences of neonatal and perinatal exposure to phthalates.

Maternal-Fetal Inflammation in the Placenta and the Developmental Origins of Health and Disease

Events in fetal life impact long-term health outcomes. The placenta is the first organ to form and is the site of juxtaposition between the maternal and fetal circulations. Most diseases of pregnancy are caused by, impact, or are reflected in the placenta. The purpose of this review is to describe the main inflammatory processes in the placenta, discuss their immunology, and relate their short- and long-term disease associations. Acute placental inflammation (API), including maternal and fetal inflammatory responses corresponds to the clinical diagnosis of chorioamnionitis and is associated with respiratory and neurodevelopmental diseases. The chronic placental inflammatory pathologies (CPI), include chronic villitis of unknown etiology, chronic deciduitis, chronic chorionitis, eosinophilic T-cell vasculitis, and chronic histiocytic intervillositis. These diseases are less-well studied, but have complex immunology and show mechanistic impacts on the fetal immune system. Overall, much work remains to be done in describing the long-term impacts of placental inflammation on offspring health.

Maternal- and Fetal-Encoded Perforin-2 Limits Placental Infection by a Bloodborne Pathogen

Placental immune responses are highly regulated to strike a balance between protection and tolerance. For relatively mild infections, protection encompasses both the mother and fetus; however, during worsening conditions, protection becomes exclusively reserved for the mother. Previously, we and others have shown that the host factor perforin-2 plays a central role in protecting mice and cells against infection. In this study, we analyzed perforin-2 activity in the mouse placenta to determine whether perforin-2 plays a similarly protective role. We show that perforin-2 is critical for inhibiting Listeria monocytogenes colonization of the placenta and fetus and that this protection is due to both maternal and fetal-encoded perforin-2. Perforin-2 mRNA is readily detectable in individual immune cells of the decidua, and these levels are further enhanced specifically in decidual macrophages during high-dose infections that result in fetal expulsion. Unexpectedly, inductive perforin-2 expression in decidual macrophages did not occur during milder infections in which fetal viability remained intact. This pattern of expression significantly differed from that observed in splenic macrophages in which inductive perforin-2 expression was observed in both high and mild infection conditions. In the placenta, inductive perforin-2 expression in decidual macrophages was coincident with their polarization from a CD206⁺ MHC class II^lo to CD206^- MHC class II^hi phenotype that normally occurs in the placenta during high-burden infections. Our results suggest that perforin-2 is part of a host response that is protective either for both the mother and fetus in milder infections or exclusively for the mother during high-dose infections.

Fetal exposure to maternal inflammation interrupts murine intestinal development and increases susceptibility to neonatal intestinal injury

Fetal exposure to chorioamnionitis can impact the outcomes of the developing fetus both at the time of birth and in the subsequent neonatal period. Infants exposed to chorioamnionitis have a higher incidence of gastrointestinal (GI) pathology, including necrotizing enterocolitis (NEC); however, the mechanism remains undefined. To simulate the fetal exposure to maternal inflammation (FEMI) induced by chorioamnionitis, pregnant mice (C57BL/6J, IL-6 ^-/-, RAG ^-/- or TNFR1 ^-/-) were injected intraperitoneally on embryonic day (E)15.5 with lipopolysaccharide (LPS; 100 µg/kg body weight). Pups were delivered at term, and reared to postnatal day (P)0, P7, P14, P28 or P56. Serum and intestinal tissue samples were collected to quantify growth, inflammatory markers, histological intestinal injury, and goblet and Paneth cells. To determine whether FEMI increased subsequent susceptibility to intestinal injury, a secondary dose of LPS (100 µg/kg body weight) was given on P5, prior to tissue harvesting on P7. FEMI had no effect on growth of the offspring or their small intestine. FEMI significantly decreased both goblet and Paneth cell numbers while simultaneously increasing serum levels of IL-1β, IL-10, KC/GRO (CXCL1 and CXCL2), TNF and IL-6. These alterations were IL-6 dependent and, importantly, increased susceptibility to LPS-induced intestinal injury later in life. Our data show that FEMI impairs normal intestinal development by decreasing components of innate immunity and simultaneously increasing markers of inflammation. These changes increase susceptibility to intestinal injury later in life and provide novel mechanistic data to potentially explain why preterm infants exposed to chorioamnionitis prior to birth have a higher incidence of NEC and other GI disorders.

Sex modifies placental gene expression in response to metabolic and inflammatory stress

INTRODUCTION

Metabolic stress (e.g., gestational diabetes mellitus (GDM) and obesity) and infections are common during pregnancy, impacting fetal development and the health of offspring. Such antenatal stresses can differentially impact male and female offspring. We sought to determine how metabolic stress and maternal immune activation (MIA), either alone or in combination, alters inflammatory gene expression within the placenta and whether the effects exhibited sexual dimorphism.

METHODS

Female C57BL/6 J mice were fed a normal diet or a high fat diet for 6 weeks prior to mating, with the latter diet inducing a GDM phenotype during pregnancy. Dams within each diet group at gestational day (GD) 12.5 received either an intraperitoneal injection of the viral mimic, polyinosinic:polycytidylic acid (poly(I:C)) or saline. Three hours post injection; placentae were collected and analyzed for changes in the expression of 248 unique immune genes.

RESULTS

Placental immune gene expression was significantly altered by GDM, MIA and the combination of the two (GDM+MIA). mRNA expression was generally lower in placentae of mice exposed to GDM alone compared with the other experimental groups, while mice exposed to MIA exhibited the highest transcript levels. Notably, fetal/placental sex influenced the responses of many immune genes to both metabolic and inflammatory stress.

DISCUSSION

GDM and MIA provoke inflammatory responses within the placenta and such effects exhibit sexual dimorphism. The combination of these stressors impacts the placenta differently than either condition alone. These findings may help explain sexual dimorphism observed in adverse pregnancy outcomes in human offspring exposed to similar stressors.

Prenatal maternal stress, fetal programming, and mechanisms underlying later psychopathology-A global perspective

There is clear evidence that the mother's stress, anxiety, or depression during pregnancy can alter the development of her fetus and her child, with an increased risk for later psychopathology. We are starting to understand some of the underlying mechanisms including the role of the placenta, gene-environment interactions, epigenetics, and specific systems including the hypothalamic-pituitary-adrenal axis and cytokines. In this review we also consider how these effects may be different, and potentially exacerbated, in different parts of the world. There can be many reasons for elevated prenatal stress, as in communities at war. There may be raised pregnancy-specific anxiety with high levels of maternal and infant death. There can be raised interpersonal violence (in Afghanistan 90.2% of women thought that "wife beating" was justified compared with 2.0% in Argentina). There may be interactions with nutritional deficiencies or with extremes of temperature. Prenatal stress alters the microbiome, and this can differ in different countries. Genetic differences in different ethnic groups may make some more vulnerable or more resilient to the effects of prenatal stress on child neurodevelopment. Most research on these questions has been in predominantly Caucasian samples from high-income countries. It is now time to understand more about prenatal stress and psychopathology, and the role of both social and biological differences, in the rest of the world.

Gestational diabetes exacerbates maternal immune activation effects in the developing brain

Maternal inflammation and diabetes increase the risk for psychiatric disorders in offspring. We hypothesized that these co-occurring risk factors may potentiate each other. To test this, we maternally exposed developing mice in utero to gestational diabetes mellitus (GDM) and/or maternal immune activation (MIA). Fetal mouse brains were exposed to either vehicle, GDM, MIA or GDM+MIA. At gestational day (GD) 12.5, GDM produced a hyperglycemic, hyperleptinemic maternal state, whereas MIA produced significant increases in proinflammatory cytokines and chemokines. Each condition alone resulted in an altered, inflammatory and neurodevelopmental transcriptome profile. In addition, GDM+MIA heightened the maternal inflammatory state and gave rise to a new, specific transcriptional response. This exacerbated response was associated with pathways implicated in psychiatric disorders, including dopamine neuron differentiation and innate immune response. Based on these data, we hypothesize that children born to GDM mothers and exposed to midgestation infections have an increased vulnerability to psychiatric disorder later in life, and this should be tested in follow-up epidemiological studies.

Maternal Peripartum Serum DDT/E and Urinary Pyrethroid Metabolite Concentrations and Child Infections at 2 Years in the VHEMBE Birth Cohort

BACKGROUND

Indoor residual spraying (IRS) of insecticides, conducted in low- and middle-income countries to control malaria, may result in high exposure to dichlorodiphenyltrichloroethane (DDT), its breakdown product dichlorodiphenyldichloroethylene (DDE), or pyrethroids. Animal studies suggest in utero exposure to these chemicals may increase childhood infection frequency.

OBJECTIVES

We investigated associations between maternal DDT/E and pyrethroid metabolite concentration and child infection associations in an IRS setting in which susceptibility factors are common and infections are leading causes of child morbidity and mortality.

METHODS

Using gas chromatography-mass spectrometry, we measured serum DDT/E and urinary pyrethroid metabolite concentrations in peripartum samples from 674 women participating in the Venda Health Examination of Mother, Babies and their Environment (VHEMBE) study. Counts of persistent child fevers, otitis media, and severe sore throat between 1 and 2 y of age were ascertained from maternal interviews. Associations between DDT/E and pyrethroid metabolite concentrations and infections were estimated using zero-inflated Poisson regression. We estimated relative excess risks due to interaction (RERI) with poverty, maternal energy intake, and maternal HIV status.

RESULTS

Concentrations of DDT/E, particularly p,p'-DDE, were associated with higher rates of persistent fevers [IRR=1.21 (95% CI: 1.01, 1.46)], for a 10-fold increase in p,p'-DDE). This association was stronger among children from households below versus above the South African food poverty line [IRR=1.31 (95% CI: 1.08, 1.59) vs. IRR=0.93 (95% CI: 0.69, 1.25), respectively] and for children whose mothers had insufficient versus sufficient caloric intake during pregnancy [IRR=1.30 (95% CI: 1.07, 1.58) vs. IRR=0.96 (95% CI: 0.72, 1.28), respectively].

CONCLUSIONS

In utero IRS insecticide exposure may increase childhood infection rates. This was particularly apparent among children from poorer households or whose mothers had low energy intake during pregnancy. https://doi.org/10.1289/EHP2657.