Gestational age is the length of time a baby has been growing in the mother's uterus during pregnancy. It is commonly used in medical settings as a way to describe the stage of fetal development. There are various ways to describe gestational age, including using synonyms like embryonic age, fetal age, conceptional age, menstrual age, or pregnancy age. Each of these terms has a specific meaning that refers to different stages of development. For example, menstrual age refers to the time that has passed since a woman's last menstrual period, while embryonic age refers to the first eight weeks of development after conception. Regardless of the term used, determining gestational age is crucial for monitoring the health and growth of the fetus.