This antibody is specific for human chorionic gonadotrophin (hCG), a 30kD hormone produced by placental syncytiotrophoblasts. hCG acts to maintain the corpus luteum until the developing placenta is able to produce the required levels of oestrogen and progesterone. hCG shares a common alpha chain with the pituitary hormones FSH, TSH and LH, but has a unique beta chain. This antibody reacts with intact hCG.