Question

What is the initial hormonal signal that starts the parturition cascade?

Options

• ACTH from the foetal pituitary gland

• Oxytocin from the maternal posterior pituitary

• Relaxin from the placenta

• Corticosteroids from the maternal adrenal gland

Answer 1

ACTH (Adrenocorticotropic Hormone) from the foetal pituitary gland is the initial hormonal signal that starts the parturition cascade. This, along with corticosteroids from the foetal adrenal gland, constitutes the fully developed foetus and placenta's signal to initiate the process of labour.