Objective: This review aimed to analyze the effects of drinking water contaminants during pregnancy on birth outcomes, focusing on chemical contaminants, including heavy metals, nitrates, and disinfection byproducts. Methods: A literature search was conducted using SCOPUS, EBSCO, PubMed, Cochrane, and Google Scholar databases. The review included English-language prospective cohort studies and clinical trials published between 2007-2022 that focused on healthy pregnant women and measured birth outcomes. From 269 articles identified, 30 met the inclusion criteria. Results: Analysis of 30 studies encompassing over 4 million births demonstrated significant associations between water contaminants and adverse birth outcomes. Arsenic exposure below 10 μg/L was associated with an increased risk of very low birth weight (AOR 1.14) and preterm birth (AOR 1.10). Nitrate concentrations of 5-10 mg/L were linked to higher rates of spontaneous preterm birth. Combined exposure to multiple contaminants demonstrated stronger effects than individual exposures, particularly during the second trimester. Conclusion: Evidence demonstrates that exposure to water pollutants during pregnancy, even at levels below current regulatory guidelines, has a significant impact on birth outcomes. Recommendations include increased monitoring during pregnancy, particularly for private well users, reviewing regulatory standards, and implementing tailored treatments for vulnerable populations. © 2025 The Author(s). Published by Bentham Open.