Investigation of Prenatal Pesticide Exposure and Neurodevelopmental Deficits in Northern Thailand: Protocol for a Longitudinal Birth Cohort Study

Abstract

Background Prenatal exposure to pesticides has been linked to adverse neurodevelopmental outcomes. Gaps exist in the current literature about the timing and magnitude of exposures that result in these adverse outcomes. Objective The Study of Asian Women and their Offspring’s Development and Environmental Exposures (SAWASDEE) cohort was established to investigate the impact of prenatal exposure to pesticides on early indicators of cognitive and motor skills, inhibitory control, emotion regulation, and memory that have been found to be important in the development of subsequent neurobehavioral and neurodevelopmental diseases. The overarching goal is to find earlier predictors of potential adverse neurologic outcomes in order to enable earlier interventions that could result in better outcome prognoses. Methods Recruitment of this prospective, longitudinal birth cohort began in July 2017 and was completed in June 2019 in Chom Thong and Fang, 2 farming districts in Chiang Mai Province in northern Thailand. Follow-up of the study participants is ongoing. During pregnancy, 7 questionnaires were administered. Time-resolved biospecimen samples were collected monthly (for urine) and during each trimester (for blood) during antenatal care visits. Medical records were abstracted. Infants were administered the NICU Network Neurobehavioral Scale (NNNS) test at 1 month of age. A total of 322 mother-child pairs completed the NNNS test. All children will be followed until 3 years of age and undergo a series of neurodevelopmental tests. We will complete several additional exposure related analyses. Results A total of 1298 women were screened, and of those, 394 (30.35%) women were enrolled. The mean gestational age at enrollment was 9.9 weeks (SD 2.6). Differences in literacy were observed between Chom Thong and Fang participants. In Fang, about 54 of 105 (51.4%) participants reported being able to read in Thai compared to about 206 of 217 (94.9%) participants in Chom Thong. The percentages were comparable for reporting to be able to write in Thai. Conclusions This longitudinal birth cohort study will inform risk assessment standards for pregnant women in Thailand and other countries. Building awareness of how insecticide exposure during specific windows of pregnancy affects the neurodevelopmental trajectories of children in developing countries is a specific need recognized by the World Health Organization. International Registered Report Identifier (IRRID) DERR1-10.2196/31696

Prenatal Pyrethroid Exposure, Placental Gene Network Modules, and Neonatal Neurobehavior

“…Recruitment took place between July 2017 and June 2019. Strict eligibility criteria were defined for participation, with detailed criteria available in Baumert et al [39]. Participants were primarily recruited in their first trimester during antenatal care visits at district hospitals and community health clinics in Chiang Mai Province, Thailand.…”

“…At five weeks post-birth, mothers and infants visited the SAWASDEE clinics as detailed in Baumert et al [39]. Infants’ weight, length, and head circumference were documented, while mothers completed the Depression Anxiety Stress Scale (DASS).…”

“…The method's validity was confirmed through participation in the GEQUAS scheme. Further details on sample preparation, analysis, and quality control, consistent with the approach outlined in Baumert et al (2022), can be found therein. To normalize metabolite concentrations, urinary creatinine was measured in each sample.…”

“…Placental collection and RNA extraction were consistent with Baumert et al (2022) [39]. Post-delivery, within a 2-hour window, five circular slices approximately 1 inch in diameter were excised from regions free of maternal decidua and around 2 cm from the umbilical cord insertion site.…”

“…Urine samples were procured and processed as outlined by Baumert et al (2022) [39]. The samples were diluted (1000-fold), creatinine analogs isotope-labeled, and analyzed via LC-MS/MS.…”