Definition

A peptide vaccine consisting of the whole or partial beta subunit of human chorionic gonadotrophin hormone (hCG), linked to an adjuvant carrier of bacterial or viral origin, with anti-fertility activity. Anti-human chorionic gonadotropin vaccine blocks the activity of hCG which is naturally produced by the trophectoderm of the pre-implantation embryo within a few days of fertilization. hCG is required for the maintenance of the corpus luteum in the ovary thus ensuring its continued production of progesterone, which is required for the successful completion of implantation of the blastocyst. Without progesterone, the corpus luteum regresses, and menstruation is initiated.