Developmental Impacts of Microplastics Exposure in Early Life

Inclusion Criteria: * All gender expressions * Mothers at 1 or 3 months postpartum (± 2 weeks) * Intent to exclusively breastfeed for ≥ 6 months * Nulliparous and singleton births * Receiving only breast milk from the mother, with no formula supplementation Exclusion Criteria: * Physical, mental, or cognitive disability that prevents participation; current incarceration * Chronic conditions in mother and/or infant (e.g., heart disease, cancer, autoimmune disease, diabetes, intestinal bowel syndrome/disease), conditions diagnosed for the first time during pregnancy (e.g. gestational diabetes), neurological conditions in mother and/or infant (e.g. epilepsy, seizures), psychological conditions in mother and/or infant (e.g. bipolar disorder), or neurological/psychological conditions diagnosed in mother during or immediately after pregnancy (e.g. postpartum depression) * Previously diagnosed with any major illness (e.g., intrauterine growth restriction, birth asphyxia, cancer) or eating disorder or previous gastric band surgery * Maternal antibiotic use during pregnancy or the postpartum period. Infant antibiotic use at any time during life or taking medications that could affect plastic exposure or the microbiome, such as medications administered via a plastic syringe. * Use of any breast pump except the Silicon Breast Pump for the 14 days prior to the clinical visit. * PHQ9 score greater than or equal to 10 indicating clinically relevant symptoms of moderate or worse depression * Infants who are intersex * Smoking, drug use (including marijuana use), or alcohol abuse