Prenatal means 'before birth': about the baby still inside, and about the care the pregnant woman receives. Prenatal care, prenatal tests, prenatal vitamins. In British hospitals you will often hear antenatal for that same care; prenatal is the American word and a lot of world medical English, and you will see it in Taiwan too. People sometimes say prenatals, casually, for the vitamin pills — that is home talk, not textbook talk. It is not a fancy word for 'about parents'. That is parental, a different word that only looks nearby. Prenatal stays in the months before the baby arrives.