from where do signals of parturition originate and what does maternal pituitary release for stimulating uterine contractions for child birth?
The signals for parturition originates from fully developed foetus and placenta which induce mild uterine contraction. This triggers release of oxytocin (birth hormone) from the maternal pituitary gland. The oxytocin starts a series of powerful contractions in the uterus to help expel the baby and limits bleeding of the placenta near the entry of the vaginal canal.
The homes that are responsible for the induction of parturition are Oxytocin and Relaxin.
Oxytocin induces the contraction of the muscles of uterus which helps the baby to move through the path downwards whereas relaxin relaxes the pelvic muscles and ligaments to help the uterus to give birth. both the hormones equally helps in parturition.