The sequence of secretion of hormones in pregnant women:
FSH⟶LH⟶hCG⟶relaxin . [1]
FSH: Follicular Stimulating Hormone is secreted by the anterior lobe of the pituitary gland. It stimulates the growth of the ovarian follicles in the ovary.
LH: Luteinizing hormone is secreted by the anterior lobe of the pituitary gland. It function is to induce ovulation. [0.5+0.5]
hCG : Human chorionic gonadotropin is secreted by the placenta. It stimulates the corpus luteum to secrete progesterone. [0.5+0.5]
Relaxin : Relaxin is secreted by the ovary and the placenta. It helps during child birth by relaxing the pelvic muuscles as well as the muscles of the cervix. [0.5+0.5]