Pregnancy is the period from conception to childbirth during which a woman carries the developing fetus, typically about 40 weeks from the last menstrual period. It is among the most nutritionally demanding states: energy needs rise modestly, but requirements for folate, iron, iodine, calcium, and protein increase substantially to build fetal tissue, expand maternal blood volume, and prepare for lactation. Key guidance includes folic acid supplementation before conception and in early pregnancy to prevent neural tube defects, adequate iron to prevent anaemia, iodine for fetal brain development, and avoidance of alcohol, high-mercury fish, raw or undercooked animal products, and unpasteurised dairy due to infection risks. Maternal nutrition shapes not only birth outcomes but the child’s long-term health, making pregnancy the highest-priority window in public health nutrition.