GESTON 5 MG is a medication containing Allylestrenol, a synthetic progesterone, used to support and maintain pregnancy, particularly in women at risk of miscarriage or premature labor. It is primarily prescribed for preventing threatened abortion, habitual abortion, and premature delivery. The drug works by promoting the secretion of progesterone, a hormone necessary for the maintenance of pregnancy. It helps in relaxing the uterine muscles, preventing premature contractions, and facilitating proper fetal development.