Definition: Teratol (from Latin "tereus", meaning womb) is a medical term used for evaluating fetal development in pregnancy. It refers to a period of time between conception and birth that is critical for the health and safety of the developing fetus. Teratol is defined as a stage of prenatal development during which the mother's body produces proteins, hormones, enzymes, and other substances that are vital for fetal growth and development. This phase typically begins around 16-20 weeks of pregnancy and continues through the first trimester of labor, when the fetus moves into the womb. The specific period during which this phase occurs can vary widely depending on individual factors such as genetic predisposition or environmental exposures. Some studies have suggested that a shorter term is associated with higher risk for complications such as low birth weight, neural tube defects (NTDs), and developmental delays in offspring. In summary, Teratol refers to the critical period during pregnancy when fetal health and safety are most at risk. It is important for healthcare providers to monitor fetal development closely during this time and to ensure that all necessary protective measures are taken to prevent or minimize potential risks.