Hydroxyprogesterone is a synthetic hormone commonly used in contraception and to prevent preterm labor. It can also be called 17-hydroxyprogesterone or 17-OHP. Other synonyms for hydroxyprogesterone include 17-hydroxypregn-4-ene-3,20-dione, delalutin, and Proluton. These terms may be used interchangeably in medical literature, but it is important to note that they all refer to the same hormone and drug. Hydroxyprogesterone works by suppressing the activity of the uterus, and it is often prescribed to women with a history of preterm birth or other high-risk pregnancies. Overall, hydroxyprogesterone is a versatile medication that has many applications in obstetrics and gynecology.