Some gases are lighter than air. Hydrogen is the lightest of all, and easily manufactured, even at home -- for example by dropping aluminium foil into a solution of sodium hydroxide (highly dangerous because it will spit droplets of hot caustic liquid at you which may blind you permanently if they land in your eyes).
The corpus luteum is essential for establishing and maintaining pregnancy in females. The corpus luteum secretes progesterone, which is a steroid hormone responsible for the decidualization of the endometrium (its development) and maintenance, respectively. It also produces relaxin, a hormone responsible for softening of the pubic symphysis which helps in parturition.
What Endometrin is used for. Endometrin is provided as a pessary (or vaginal tablet) that contains the natural female hormone, progesterone. Endometrin is for women who need extra progesterone while undergoing treatment in an Assisted Reproductive Technology (ART) programme (e.g. IVF). Progesterone acts on the lining of the uterus (womb) and it helps you to become and to stay pregnant when you are treated for infertility. Your doctor may have prescribed Endometrin for another purpose. Ask your doctor if you have any questions why this medicine has been prescribed for you.