Final answer:
The hormone responsible for preparing the uterus for the implantation of a fertilized egg is progesterone. This hormone, produced by the corpus luteum and the placenta, inhibits further FSH and LH release, preventing new follicles from developing and suppressing uterine contractions to facilitate implantation.
Step-by-step explanation:
The progestin hormone responsible for the preparation of the uterus for the implantation of a fertilized egg is called progesterone. Progesterone is produced by the corpus luteum and, during pregnancy, is also produced by the placenta. It plays a crucial role in maintaining a successful pregnancy by inhibiting the release of further FSH (follicle-stimulating hormone) and LH (luteinizing hormone) which in turn prevents new ovarian follicles from developing while also suppressing uterine contractility to allow for the fertilized egg to implant and develop.
In addition to its role in the menstrual cycle and pregnancy, progesterone is synthesized from cholesterol and can be found in the blood bound to cortisol binding globulin or transcortin. It is evident that progesterone, along with estrogens and hCG (human chorionic gonadotropin), are pivotal in virtually all of the effects and changes experienced during pregnancy.