Final answer:
The hormone responsible for stimulating the release of estrogen and progesterone after fertilization is human chorionic gonadotropin (hCG). It is crucial for maintaining the pregnancy by preserving the corpus luteum, which secretes progesterone.
Step-by-step explanation:
The hormone that stimulates the release of estrogen and progesterone after fertilization is known as human chorionic gonadotropin (hCG). After fertilization, when a zygote forms and progresses to a blastocyst, the outer layer of the blastocyst produces hCG. This hormone is notably similar to luteinizing hormone (LH) and serves a crucial role in preserving the corpus luteum, which is necessary for maintaining a new pregnancy by continuing to secrete progesterone.
Moreover, LH is integral in the development of ova, induction of ovulation, and stimulation of estradiol and progesterone production by the ovaries. These steroid hormones, estradiol and progesterone, prepare the body for pregnancy. Despite FSH and LH being involved earlier in the cycle to stimulate follicle maturation and estrogen production, it is hCG that takes over to maintain the production of these hormones after fertilization has occurred.