Acetaminophen (APAP), an antipyretic and analgesic commonly used during pregnancy, has been recognized as a novel environmental contaminant. Preliminary evidence suggests that prenatal acetaminophen exposure (PAcE) could adversely affect offspring's gonadal and neurologic development, but there is no systematic investigation on the characteristics of APAP's fetal developmental toxicity. Pregnant mice were treated with 100 or 400 mg/kg∙d APAP in the second-trimester, or 400 mg/kg∙d APAP in the second- or third-trimester, or different courses (single or multiple) of APAP, based on clinical regimen. The effects of PAcE on pregnancy outcomes, maternal/fetal blood phenotypes, and multi-organ morphological and functional development of fetal mice were analyzed. PAcE increased the incidence of adverse pregnancy outcomes and altered blood phenotypes including aminotransferases, lipids, and sex hormones in dams and fetuses. The expression of key functional genes in fetal organs indicated that PAcE inhibited hippocampal synaptic development, sex hormone synthesis, and osteogenic and chondrogenic development, but enhanced hepatic lipid synthesis and uptake, renal inflammatory hyperplasia, and adrenal steroid hormone synthesis. PAcE also induced marked pathological alterations in the fetal hippocampus, bone, kidney, and cartilage. The sensitivity rankings of fetal organs to PAcE might be hippocampus/bone > kidney > cartilage > liver > gonad > adrenal gland. Notably, PAcE-induced multi-organ developmental toxicity was more considerable under high-dose, second-trimester, and multi-course exposure and in male fetuses. This study confirmed PAcE-induced alterations in multi-organ development and function in fetal mice and elucidated its characteristics, which deepens the comprehensive understanding of APAP's developmental toxicity.

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) represents a critical developmental concern because several PFAS cross the placenta and may perturb biological programming during sensitive windows. Although epidemiological and experimental studies have linked prenatal exposure to several measured PFAS, primarily legacy perfluoroalkyl acids such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), Perfluorohexane Sulfonic Acid (PFHxS), and Perfluorononanoic Acid (PFNA), to diverse offspring outcomes, the strength of evidence differs substantially across compounds and health domains. Current human evidence is strongest for impaired vaccine antibody responses and altered growth or metabolic trajectories in studies dominated by legacy PFAS, whereas evidence for other congeners, short-chain PFAS, ether-based alternatives, and fluorotelomer compounds remains sparse. Mechanistically, placental transfer, nuclear receptor perturbation, thyroid hormone transport disruption, mitochondrial stress, immune modulation, and epigenetic reprogramming may jointly contribute to developmental susceptibility. We further discuss how emerging PFAS alternatives and real-world mixture exposures challenge single-chemical and adult-centered assessment paradigms. Finally, we outline a conceptual framework for developmental hazard assessment, in which exposure-window characterization, congener-specific toxicokinetics, human-relevant models, multi-omics biomarkers, and PBPK/PBTK modeling are positioned as complementary components rather than as a fully operational assessment system.